Recycling lithium-ion batteries from electric vehicles

Abstract

Rapid growth in the market for electric vehicles is imperative, to meet global targets for reducing greenhouse gas emissions, to improve air quality in urban centres and to meet the needs of consumers, with whom electric vehicles are increasingly popular. However, growing numbers of electric vehicles present a serious waste-management challenge for recyclers at end-of-life. Nevertheless, spent batteries may also present an opportunity as manufacturers require access to strategic elements and critical materials for key components in electric-vehicle manufacture: recycled lithium-ion batteries from electric vehicles could provide a valuable secondary source of materials. Here we outline and evaluate the current range of approaches to electric-vehicle lithium-ion battery recycling and re-use, and highlight areas for future progress. Processes for dismantling and recycling lithium-ion battery packs from scrap electric vehicles are outlined.

Full text

Nature | Vol 575 | 7 November 2019 | 75
Review
Recycling lithium-ion batteries from electric
vehicles
Gavin Harper1,2,3*, Roberto Sommerville1,2,4, Emma Kendrick1,2,3, Laura Driscoll1,2,5,
Peter Slater1,2,5, Rustam Stolkin1,2,3,6, Allan Walton1,2,3, Paul Christensen1,7, Oliver Heidrich1 ,7,8 ,
Simon Lambert1,7, Andrew Abbott1,9, Karl Ryder1,9, Linda Gaines10 & Paul Anderson1,2,5*
Rapid growth in the market for electric vehicles is imperative, to meet global targets
for reducing greenhouse gas emissions, to improve air quality in urban centres and to
meet the needs of consumers, with whom electric vehicles are increasingly popular.
However, growing numbers of electric vehicles present a serious waste-management
challenge for recyclers at end-of-life. Nevertheless, spent batteries may also present an
opportunity as manufacturers require access to strategic elements and critical
materials for key components in electric-vehicle manufacture: recycled lithium-ion
batteries from electric vehicles could provide a valuable secondary source of materials.
Here we outline and evaluate the current range of approaches to electric-vehicle
lithium-ion battery recycling and re-use, and highlight areas for future progress.
The electric-vehicle revolution, driven by the imperatives to decarbonize
personal transportation in order to meet global targets for reductions
in greenhouse gas emissions and improve air quality in urban centres, is
set to change the automotive industry radically. In 2017, sales of electric
vehicles exceeded one million cars per year worldwide for the first time1.
Making conservative assumptions of an average battery pack weight
of 250 kg and volume of half a cubic metre, the resultant pack wastes
would comprise around 250,000 tonnes and half a million cubic metres
of unprocessed pack waste, when these vehicles reach the end of their
lives. Although re-use and current recycling processes can divert some
of these wastes from landfill, the cumulative burden of electric-vehicle
waste is substantial given the growth trajectory of the electric-vehicle
market. This waste presents a number of serious challenges of scale; in
terms of storing batteries before repurposing or final disposal, in the
manual testing and dismantling processes required for either, and in
the chemical separation processes that recycling entails.
Given that the environmental footprint of manufacturingelectric
vehicles is heavily affected by theextraction of raw materials and pro-
ductionof lithium ion batteries, the resulting waste streams will inevi-
tably place different demands on end-of-life dismantling and recycling
systems. In the waste management hierarchy, re-use is considered pref-
erable to recycling (Fig.1). Because considerable value is embedded in
manufactured lithium-ion batteries (LIBs), it has been suggested that
their use should be cascaded through a hierarchy of applications to
optimize material use and life-cycle impacts2. Markets for energy storage
are under development as energy regulators in various locations transi-
tion to cleaner energy sources. Energy storage is particularly sought-
after in areas where weak grids require reinforcement, where high
penetration of renewables requiressupply to be balanced with demand,
where there is an opportunity for trading energy with the grid and in off-
grid applications. Second-use battery projects have started to develop
in locations where there is regulatory and market alignment. However,
large concentrations of waste—be it for refurbishment, re-manufacture,
dismantling or final disposal—can create substantial challenges. A fire
in stockpiled tyres in Powys, Wales, for example, smouldered for fifteen
years from 1989 to 2004. Since the electrode materials in LIBs are far
more reactive than tyre rubber3, without a proactive and economically
sound waste-management strategy for LIBs there are potentially greater
dangers associated with stockpiling of end-of-life LIBs. Already the
number of fires being reported in metal-recovery facilities is increas-
ing4, owing to the illicit or accidental concealment of (consumer) LIBs
in the guise of, for example, lead–acid batteries. Among examples of
recent major fires are those that took place in metal-recovery facilities
in Shoreway, San Carlos, USA, in September 20165, Guernsey in August
2018 and Tacoma, Washington, USA, in September 2018.
Waste may also represent a valuable resource. Elements and materials
contained in electric-vehicle batteries are not available in many nations
and access to resources is crucial in ensuring a stable supply chain. In the
future, electric vehicles may prove to be a valuable secondary resource
for critical materials, and it has been argued that high-cobalt-content
batteries should be recycled immediately to bolster cobalt supplies6.
If tens of millions of electric vehicles are to be produced annually, care-
ful husbandry of the resources consumed by electric-vehicle battery
manufacturing will surely be essential to ensure the sustainability of
the automotive industry of the future, as will a material- and energy-
efficient 3R system (reduce, re-use, recycle). Here we give an overview
https://doi.org/10.1038/s41586-019-1682-5
Received: 14 January 2019
Accepted: 23 July 2019
Published online: 6 November 2019
1Faraday Institution, ReLiB Project, University of Birmingham, Birmingham, UK. 2Birmingham Centre for Strategic Elements and Critical Materials, University of Birmingham, Birmingham, UK.
3School of Metallurgy and Materials, University of Birmingham, Birmingham, UK. 4School of Chemical Engineering, University of Birmingham, Birmingham, UK. 5School of Chemistry,
University of Birmingham, Birmingham, UK. 6National Centre for Nuclear Robotics, University of Birmingham, Birmingham, UK. 7School of Engineering, Newcastle University, Newcastle, UK.
8Tyndall Centre for Climate Change Research, Newcastle University, Newcastle, UK. 9Materials Centre, University of Leicester, Leicester, UK. 10ReCell Center, Argonne National Laboratory,
Lemont, IL, USA. *e-mail: g.d.j.harper@bham.ac.uk; p.a.anderson@bham.ac.uk
Anniversary
collection:
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Waste management hierarchy
Prevention
Re-use
Recycling
Recovery
Disposal
Advanced battery recycling: automated disassembly
Present battery recycling: shredding, pyrometallurgy
Range of recycling technologies
Recycling
Complexity
of process
‘Mixing’ of
materials
streams
Amount of
materials
recovered
Value of
materials
recovered
Fig. 1 | The wa ste managem ent hierarchy a nd range of recycl ing options . The
waste mana gement hierarchy i s a concept that w as developed from t he Council
Directi ve 75/442/EEC of 15 July 1975 (https://eur-lex.europa.eu/legal-content/
EN/TXT/?uri=CELEX%3A31975L0442) on waste by the Dutch p olitician Ad
Lansink, i n 1979, who presented to the D utch parliamen t a simple schemat ic
represen tation that ha s been terme d ‘Lansink ’s Ladder’, ranking wa ste
managemen t options fro m the most to lea st environmen tally desira ble options .
Here, that hi erarchy is expande d to consider the r ange of batter y recycling
technolo gies. ‘Preve ntion’ means t hat LIBs are des igned to use le ss-critica l
materials (high economic importance, but at risk of short supply) and that
electr ic vehicles shoul d be lighter and have sm aller batteri es. ‘Re-use ’ means
that elec tric-vehicle bat teries shoul d have a second use . ‘Recycling’ m eans that
batteri es should be rec ycled, recovering a s much material a s possible and
preser ving any struc tural value and qual ity (for example, prevent ing
contamination). ‘Recovery’ means using some battery materials as energy for
process es such as fue l for pyrometall urgy. Finally, ‘disposal ’ means that no v alue
is recovered an d the waste goes to l andfill.
76 | Nature | Vol 575 | 7 November 2019
Review
of the current state of the art and identify some of the important issues
relating to the end-of-life management of electric-vehicle LIBs.
Social and environmental impacts of LIBs
If we consider the two main modes of primary production, it takes
250 tons of the mineral ore spodumene7,8 when mined, or 750 tons of
mineral-rich brine7,8 to produce one ton of lithium. The processing of
large amounts of raw materials can result in considerable environmental
impacts9. Production from brine, for example, entails drilling a hole in
the salt flat, and pumping of the mineral-rich solution to the surface.
However, this mining activity depletes water tables. In Chile’s Salar de
Atacama, a major centre of lithium production, 65% of the region’s water
is consumed by mining activities9. This affects farmers in the region who
must then import water from other regions. The demands on water
from the processing of lithium produced in this way are substantial,
with a ton of lithium requiring 1,900 tons of water to extract, which is
consumed by evaporation9.
By contrast, secondary production would require only 28 tons of
used LIBs7,8,10 (around 256 used electric-vehicle LiBs8). The net impact
of LIB production can be greatly reduced if more materials can be
recovered from end-of-life LIBs, in as close to usable form as possible11.
However, in the rapid-growth phase of the electric-vehicle market,
recycling alone cannot come close to replenishing mineral supplies12.
LIBs are anticipated to last 15–20years12 based on calendar aging
(the aging due to time since manufacture) predictions—three times
longer than lead–acid batteries12. Initial concerns regarding
resource constraints for LIB production scale-up focused on lithium
13
;
however, in the near term, reserves of lithium are unlikely to present a
constraint14,15.
Of greater immediate concern are cobalt reserves16, which are geo-
graphically concentrated (mainly in the politically unstable Democratic
Republic of the Congo). These have experienced wild short-term price
fluctuations and raise multifarious social, ethical and environmental
concerns around their extraction, including artisanal mines employing
child labour17. In addition to the environmental imperative for recycling,
there are clearly serious ethical concerns with the materials supply
chain, and these social burdens are borne by some of the world’s most
vulnerable people. Given the global nature of the industry, this will
require international coordination to support a concerted push towards
recycling LIBs and a circular economy in materials18.
Battery assessment and disassembly
The waste-management hierarchy considers re-use to be preferable to
recycling (Fig.1). As considerable value is embedded in manufactured
LIBs, it has been suggested that their use should be cascaded through
a hierarchy of applications to optimize material use and life-cycle
impacts
2
. Energy stored over energy invested (ESOI)—the ratio between
the energy that must be invested into manufacturing the battery and the
electrical energy that it will store over its useful life—is a metric used to
compare the efficacy of different energy-storage technologies. Clearly,
ESOI figures will improve if end-of-life electric-vehicle batteries can be
used in second-use applications for which the battery performance is
less critical.
Profitable second-use applications also provide a potential value
stream that can offset the eventual cost of recycling, and already a
healthy market is developing in used electric-vehicle batteries for energy
storage in certain localities, with demand potentially outstripping sup-
ply. For the moment the economics of the decision whether to recycle
or re-use are set firmly in favour of re-use. The main factors are (1) the
refurbishment cost of putting the battery into a second-use application
and (2) any credit that would accrue as the result of recycling the bat-
tery instead; if the second-use price were to fall below the sum of the
refurbishment cost and the recycling credit, then recycling would be
the economically favoured option
19
. In time, it is anticipated
19
that the
supply of used electric-vehicle batteries will far exceed the quantity that
the second-use market can absorb. It must be remembered, therefore,
that—if disposal to landfill is to be avoided—recycling must be the ulti-
mate fate of all LIBs, even if they first have a second use.
Given that stockpiling of waste batteries is potentially unsafe and
environmentally undesirable, if direct re-use of an LIB module is not
possible, it must be repaired or recycled. End-of-life LIB recycling could
provide important economic benefits, avoiding the need for new min-
eral extraction
20
and providing resilience against vulnerable links
21
and supply risks
22
in the LIB supply chain. For most remanufacture and
recycling processes, battery packs must be disassembled to module
level at least. However, the hazards associated with battery disassem-
bly are also numerous
23,24
. Disassembly of battery packs from automo-
tive applications requires high-voltage training and insulated tools
to prevent electrocution of operators or short-circuiting of the pack.
Short-circuiting results in rapid discharge, which may lead to heating
and thermal runaway. Thermal runaway may result in the generation of
particularly noxious byproducts, including HF gas
25
, which along with

Nature | Vol 575 | 7 November 2019 | 77
other product gases may become trapped and ultimately result in cells
exploding
23
. The cells also present a chemical hazard owing to the flam-
mable electrolyte, toxic and carcinogenic electrolyte additives, and the
potentially toxic or carcinogenic electrode materials.
Diagnostics of battery pack, modules and cells
‘State of health’ is the degree to which a battery meets its initial design
specifications. Over time as the battery degrades, its performance var-
ies from its initial condition. The units are percentage points, with 100%
indicating a state of health that is identical to that of a new battery meet-
ing its design specification. (Some new batteries may leave the factory
deviating from design specifications, and having less than 100% state of
health.) The ‘state of charge’ is the degree to which a battery is charged
or discharged. Again, the units are percentage points, with 0% indicating
empty and 100% indicating full).
Battery repurposing—the re-use of packs, modules and cells in other
applications such as charging stations and stationary energy storage—
requires accurate assessment of both the state of health, to categorize
whether batteries are best suited for re-use (and if so, for which applica-
tions), remanufacture or recycling, and the state of charge, for safety
reasons in some recycling processes. For high-throughput triage and
gateway testing of batteries at scale, the optimal approach involves
insitu techniques for monitoring cells in service to enable advance
warning of possible cell replacement, and module or pack recondition-
ing, rather than complete repurposing at a low level of state of health
owing to a few failing cells.
Electrochemical impedance spectroscopy can give information on
the state of health of cells, modules and, potentially, full packs26, and
also an indication of aging mechanisms such as lithium plating. Such
measurements have the potential to inform a decision matrix for re-use
or disassembly and processing and, importantly, to identify potential
hazards that would have further consequences for downstream process-
ing. Electrochemical impedance spectroscopy has been researched for
gateway testing in primary production, for example,in a large battery
production plant in the UK27,28. A number of electric-vehicle manufactur-
ers plan to use similar technologies to manage and maintain electric-
vehicle battery packs through the identification and replacement of
failing modules in the field. Substantial advantages in cost, safety and
throughput time are anticipated if this process can be mostly or fully
automated27,29. In future, more advanced diagnostic functionality will
be embedded in battery management systems, providing data that can
be interrogated at end-of-life.
Challenges of pack and module disassembly
Different vehicle manufacturers have adopted different approaches
for powering their vehicles, and electric vehicles on the market pos-
sess a wide variety of different physical configurations, cell types
and cell chemistries. This presents a challenge for battery recycling.
Figure2 details three different types of battery cell design, and their
respective packs from electric vehicles in the marketplace from model
year 2014. It can be seen that the three vehicles possess very differ-
ent physical configurations, requiring different approaches for dis-
assembly, particularly regarding automation. It can be seen in Fig.2
that at the different scales of disassembly, the format and relative size
of the different components differ, presenting challenges for auto-
mation. The differing form factors and capacities may also restrict
applications for re-use. And finally, Fig.2 illustrates that manufactur-
ers employ varying cell chemistries (see Fig.3), which will necessitate
different approaches to materials reclamation and strongly affect the
overall economics of recycling. Whereas the prismatic and pouch cells
have planar electrodes, the cylindrical cells are tightly coiled, presenting
additional challenges to separating the electrodes for direct recycling
processes.
For repurposing and second-use applications, automotive battery
packs are currently dismantled by hand for either the second use of
the modules or for recycling. The weights and high voltages of trac-
tion batteries mean that qualified employees and specialized tools are
required for such dismantling
25
. This is a challenge for an industry in
transition with a shortage of skills. An Institute of the Motor Industry
survey found only 1,000 trained technicians in the UK capable of servic-
ing electric vehicles30, with another 1,000 in training. Given there are
170,000 motor technicians in the UK, this represents less than 2% of the
workforce. There is concern that untrained mechanics may risk their
lives repairing electric vehicles31, and these concerns logically extend
to those handling vehicles at the end-of-life. Additionally, it has been
suggested
32
that manual dismantling, in countries with high labour
costs, is uneconomic with respect to revenues from extracted materi-
als or components. Vehicle design has to strike compromises between
crash safety, centre of gravity and space optimization, which must be
balanced against serviceability25. These conflicting design objectives
often result in designs that are not optimized for recyclability, and that
can be time-consuming to disassemble manually25.
Automating battery disassembly
Robotic battery disassembly could eliminate the risk of harm to human
workers, and increased automation would reduce cost, potentially mak-
ing recycling economically viable. This is being piloted in a number
of current research projects33–36. Importantly, automation could also
improve the mechanical separation of materials and components,
enhancing the purity of segregated materials and making downstream
separation and recycling processes more efficient. The automation of
the dismantling of automotive batteries, however, presents major chal-
lenges. This is because robotics and automation in the manufacturing
sector rely on highly structured environments, in which robots make pre-
programmed repetitive actions with respect to exactly known objects
in fixed positions. In contrast, the development of robotic systems that
can generalize to a variety of objects, and handle uncertainty, remains
a major challenge at the frontier of artificial intelligence research. It is
important to consider the complexity of vehicle battery disassembly
from this perspective.
At present there is no standardization37 of design for battery packs,
modules or cells within the automotive sector, and it is unlikely that
this will happen in the near future. Other battery-reliant products, such
as mobile phones, have seen an exponential proliferation of different
sizes, shapes and types of battery over the past two decades. At present,
much of the factory assembly of these batteries is done by human work-
ers and remains unautomated. Their disassembly and waste-handling
typically involve even less structured environments, with much greater
uncertainties, than a manufacturing assembly line.
Nevertheless, some progress has been made towards automated
sorting of consumer batteries. The Optisort system
38,39
uses computer
vision algorithms to recognize the labels on batteries, and then pneu-
matic actuators to segregate batteries into different bins according to
their type of chemistry. However, Optisort is currently limited to AA and
AAA batteries, and a large amount of pre-sorting by hand is needed to
separate these from mixed batches of waste batteries, prior to entering
the Optisort machine.
The Society for Automotive Engineers and the Battery Association
of Japan have both recommended labelling standards for electric-
vehicle batteries. Recent algorithms from computer vision research
have some capability to recognize objects and materials on the basis
of features such as size, shape, colour and texture. However, it could be
advantageous for recycling if manufacturers were to (some manufactur-
ers already do) include labels, QR Codes, RfID tags or other machine-
readable features on key battery components and sub-structures.
Where these provide a reference to an external data source, its utility
in aiding the recycling process will depend on the accessibility and
format of that data. If proprietary and private, such data are of limited
use, but there may be initiatives to move towards standardization and
open data formats. A number of companies are considering blockchain

technologies to provide whole-life-cycle tracking of battery materials,
including information and transparency on provenance, ethical sup-
ply chains, battery health and previous use
40
.China has signalled its
intention to track battery materials.
Automated disassembly of electrical goods has also been imple-
mented to some extent in other sectors. For example, Apple has imple-
mented an automated disassembly line for the iPhone 641 that can handle
1.2 million phones per year. This line has 22 stations linked on a conveyor
system and can take the iPhone apart in 11 seconds. However, this system
can only deal with an iPhone 6 model. Intact phones, of this exact model,
must be positioned at the start of the disassembly line, which then uses
pre-programmed motions of 29 robots in 21 different cells to dismantle
the phone into 8 discrete parts. The LIB is removed by heating the glue
which holds the battery in place. Owing to the potential fire hazard,
this must take place inside a thermal event protection system, while
monitoring the battery using a thermal imaging system.
Unfortunately, 1.2 million phones per year is a drop in the ocean
and the Apple disassembly line has been created using conventional
industrial automation methods, making it inflexible and incapable of
keeping up adaptively with new models and varieties of phones. But
building a flexible and adaptable robot disassembly line need not be pro-
hibitively expensive. The challenge is to create control algorithms and
software that can make cheap hardware (robot arms cost only several
thousands to several tens of thousands of dollars and costs have been
steadily decreasing, can work all the time, and have very long service
lifetimes) behave flexibly and intelligently to handle hugely complex
disassembly problems. If those artificial intelligence challenges can
be solved, then the capital investment required to respond to new and
Ø 18 mm
Nissan Leaf Mk1 22-kWh battery packBMW i3 Mk1 22-kWh battery packTesla model S 85 Mk1 kWh battery pack
Pack
Module
Cell
48.5 g
127 mm
265 mm
259 mm
Cylindrical Prismatic Pouch
35 mm
79 mm
123 mm
Cells shown at
magnication of
10 relative to rest
of diagram
8 modules per pack 16 modules per pack
7.9 mm
444 cells per module
150 mm
294 kg
NCA cathode
Graphite anode
360 V
3.6 V
AESCSamsung/SDIPanasonic
235 kg
355.2 V
530 kg
375 V
48 modules per pack
25 kg 24.5 kg 3.8 kg
2,830 mm
1,660 mm
1,772 mm
963 mm
1,570 mm 1,188 mm
302 mm 360 mm311 mm 225 mm 303 mm
65 mm
12 cells per module 4 cells per module
2 kg
NMC cathode
Graphite anode
3.7 V
914 g
LMO/NMC cathode
Graphite anode
3.75 V
173 mm
45 mm
225 mm 260 mm
665 mm
Fig. 2 | Examp les of three di fferent ba ttery pack s and module s (cylindrical ,
prismat ic and pouch ce lls) in use in cur rent elect ric cars. Th e three desig ns
examined are f rom model year 2014; this i s based on the avail ability of
informatio n from vehicle teard owns, and also be cause older veh icles are more
likely to be clos er to end-of-life than tod ay’s new cars. The b reakdowns includ e
material co ntent in a cell, layout a nd content of the m odule and pack and t he
proport ion of critical e lements (hig h economic imp ortance, b ut at risk of shor t
supply) and stra tegic materi als (either high eco nomic impor tance or risk of
short supp ly) used. The Nis san pouch cell s from Automotive En ergy Supply
Corporat ion (AESC) exhi bit a mixed catho de chemistr y with substa ntial
mangane se content and re latively low levels of co balt. The Tesla cylin drical
18650 cell s from Panaso nic and the BMW pr ismatic cel ls from Samsun g SDI both
contain hi gh cobalt levels. E ach cell has par ticular recycli ng challenges .
Cylindric al cells are ofte n bonded into a mo dule using epox y resin (diffic ult to
remove or recycle); fus es at each end may b e blown, making c ell discharge
challengi ng; and the cell ge ometry can b e difficu lt to dismantle for dire ct
recycling. P rismatic ce lls require ‘can ope ning’ (requiring s pecial tools) to
remove the cont ents. The se large cells are und er considerab ly more pressure
than are the po uch or cylindri cal cells, and c an therefore be ha zardous to ope n if
the conten ts have degass ed. The high ma nganese con tent of the Niss an pouch
cells makes pyrometallurgical recycling less cost-effective, because manganese
is cheap, but th ese cells are t he least prob lematic to op en and physical ly separate
for direct recycling.
78 | Nature | Vol 575 | 7 November 2019
Review

changing models could be kept remarkably low (mainly software
updates would be needed). Making robots behave intelligently will
rely heavily on sensors to enable advanced robotic perception, espe-
cially computer vision using three-dimensional RGB-D imaging devices,
combined with bespoke sensors from materials and battery experts. The
robots will also require tactile and force-sensing capabilities to handle
the complex dynamics problems of forceful interactions between the
robots and the materials being disassembled.
Owing to the complexity of automotive battery packs, the possibil-
ity of collaborative human–robot co-working using a new generation
of force-sensitive ‘co-bot’ robot arms
33,42
has been suggested. Unlike
conventional industrial robots, these co-bots can safely share a work-
space with humans, and Wegener
33
suggests that the robot could be
taught tasks such as unscrewing bolts, while the human handles cog-
nitively more complex tasks. However, this approach does not protect
the human worker from battery hazards and even the task of locating
a bolt, moving a tool to engage with it, unscrewing and removing it
represents a cutting-edge research challenge in robotics and machine
vision. Using current industrial robotics methods, the problem only
becomes attemptable (but still difficult) provided that the position
of the bolt head is always exactly fixed, in a known pose relative to the
robot, with very high precision.
State-of-the-art robotics, computer vision and artificial-intelligence
capabilities for handling diverse waste materials do exist, and these
systems have demonstrated sufficient robustness and reliability to gain
acceptance by the UK nuclear industry, for example, in the deployment
of artificial-intelligence-controlled, machine-vision-guided robotic
manipulation for cutting of contaminated waste material in radioac-
tive environments43. These technologies are now being adapted to the
demanding problem of robotic battery disassembly. At different scales
of disassembly—pack removal, pack disassembly, module removal and
cell separation—different challenges and barriers to automation exist.
Some of these are set out in Fig.4. Computer-vision algorithms are being
developed that can identify diverse waste materials and objects
44
, reli-
ably track objects in complex, cluttered scenes
45
, and dynamically guide
the actions of robot arms46. Dismantling requires forceful interaction
between robots and objects, engendering complex dynamics and con-
trol problems, such as simultaneous force and motion control
47
, which
is needed for robotic cutting or unscrewing. Dismantled materials must
be grasped and manipulated, including fragmented or deformable
materials, which pose challenges both to vision systems and autono-
mous grasp planners. Adjigble etal.48 have recently demonstrated
state-of-the-art performance in autonomous, vision-guided robotic
grasping of arbitrary objects from random, cluttered heaps. These
advances in computer vision, artificial intelligence and robotics funda-
mentals offer exceptionally promising tools with which to approach the
extremely difficult open research challenge of automated disassembly
of electric-vehicle batteries.
Stabilization and passivation of end-of-life batteries
Once LIBs have been designated for recycling, the three main processes
involved consist of stabilization, opening and separation, which may
be carried out separately or together. Stabilization of the LIB can be
achieved through brine or Ohmic discharge. In-process stabilization
during opening, however, is the current route preferred in industry, as
it minimizes costs. This consists of shredding or crushing the batteries
in an inert gas such as nitrogen, carbon dioxide, or a mixture of carbon
dioxide and argon. State-of-the art physical processing of LIBs in Europe
and North America includes the Recupyl
8
(France), Akkuser
49
(Finland),
Duesenfeld
50
(Germany) and Retriev
51
(USA/ Canada) processes. Large-
scale European processes do not currently use stabilization techniques
prior to breaking cells open, instead opting for opening under an inert
atmosphere of carbon dioxide or argon (with less than 4% molecular
oxygen). Opening under carbon dioxide allows for the formation of a
passivating layer of lithium carbonate on any exposed lithium metal.
The Retriev process differs from the European processes in that it uses
LIB cathode chemistries
Cathode
typesLCO LFPLMO NCANMC
Chemical
formula LiCoO2LiFePO4 (NMC111)
(NMC532)
(NMC622)
(NMC811)
Structur
eLayeredOlivine SpinelLayered Layered
Ye
ar introduced 19911996199619992008
Saf
ety
Ener
gy density
P
ower density
Calendar
lifespan
Cy
cle lifespan
Pe
rformance
Cost
Mark
et shareObsolete Electric bikes, buses
and large vehicles
SmallSteadyGrowing (from NMC 111 > NMC 532 > NMC 622 >
NMC 811 to no-cobalt chemistries)
IdealPoor
LiMn2O4Li(Ni,Co,Al)O2LiNi0.33Mn0.33Co0.33O2
LiNi0.5Mn0.3Co0.2O2
LiNi0.6Mn0.2Co0.2O2
LiNi0.8Mn0.1Co0.1O2
Fig. 3 | LIB ca thode chemi stries. T he term LIB cover s a range of differen t
batter y chemistri es, each with di fferent per formance attr ibutes. Th e basic
concept of a L IB is that lithium c an intercalate i nto and out of an ope n structure,
which consists of either ‘layers’ or ‘tunnels’. Generally the anode is graphite but
the catho de material may have dif ferent chemis tries and str uctures, whi ch
result in dif ferent perfor mance attri butes and there ar e trade-off s and
compromis es with each te chnology. The c athode chemi stries of LIB s have a
large impac t on the perform ance of LIBs, and t hese chemis tries have evolved
and improved. Fi g.3 presents a sum mary of the dif ferent LiB cathod e
chemistries.
Nature | Vol 575 | 7 November 2019 | 79

a water spray during the opening step51. The water hydrolyses any
exposed lithium and acts as a heatsink, preventing thermal runaway
during opening.
Discharging through salt solutions or ‘brine’ (seawater has been used
previously
52,53
) is an alternative method that is supposed to render the
cells safe via the corrosion and subsequent water leaching into the cells
that passivates the internal cell chemistries. Aqueous solutions of halide
salts have been shown to result in substantial corrosion at the battery
terminal ends, whereas alkali metal salts, such as sodium phosphate,
produce much less corrosion with no water penetration, offering the
possibility that cells could be assessed and re-used
53
. This represents a
considerably safer discharging method than using seawater; however,
competing electrochemical reactions do occur. Oxygen, hydrogen and
other gases, such as chlorine (depending upon the salts in the brine),
will form at the anode and cathode terminals, and can potentially be col-
lected, though the dangers and difficulties associated with this should
not be underestimated. The time for complete discharge is dependent
on the solubility of the salt and hence the conductivity of the solution;
increasing the temperature will also shorten the discharge time. Once
discharge is complete, the cell components can be separated into dif-
ferent materials streams for further processing: steel can or laminated
aluminium, separator, anode (graphite, copper, conductive additive),
binder and cathode (active material, aluminium, carbon black, binder).
The brine discharge method is not suitable for high-voltage modules
and packs, owing to the high rate of electrolysis and vigorous evolution
of gases that would occur. However, for low-voltage modules and cells
(or once a high-voltage pack has been dismantled into its constituent
components) where the electrolysis can be more carefully controlled,
this could, in principle, offer a method of discharge in which the hydro-
gen and oxygen could be recovered for other applications, adding to
the cost-effectiveness of the process
54
. The downside, however, is that
contamination of the cell contents threatens to complicate the down-
stream chemical processes or compromise the value of processed
materials streams.
An alternative to the use of salt solutions is direct Ohmic discharge
of the battery through a load-bearing circuit. If the electricity can be
reclaimed from the discharge, this could offset some of the cost of fur-
ther processing. To put it into context, the domestic consumption of
a standard UK home is up to 4,600kWh per year. So a 60-kWh battery
pack at a 50% state of charge and a 75% state of health has a potential
22.5kWh for end-of-life reclamation, which would power a UK home for
nearly 2 hours. At 14.3 p per kWh, this equates to UK£3.22 per pack, which
may seem a modest gain that does not warrant the cost of investing in
equipment. However, if it is unrecovered, the energy from discharge
must be dissipated, and this will add to the cooling burden of the facil-
ity, creating additional costs. Furthermore, an economy of scale is to be
anticipated when recycling electric vehicle batteries in bulk. Similarly,
reclaimed energy might make a useful contribution to the profitability
of repurposing for second use (see section ‘Battery assessment and
disassembly’).
LIB cells can be shredded at various states of charge, and from a com-
mercial point of view, if discharged modules or cells are to be processed
in this way, discharge prior to shredding adds cost to the processes.
Furthermore, exactly what the optimum level of discharge might be
remains unclear. Depending on cell chemistry and depth of discharge,
over-discharging of cells can result in copper dissolution into the elec-
trolyte. The presence of this copper is detrimental for materials recla-
mation as it may then contaminate all the different materials streams,
including the cathode and separator. If the voltage is then increased
again or ‘normal’ operation resumed55, this can be dangerous because
Cell
Module
Pack
• Bolts and fixings may be rusted
• Heads of fixings may be rounded or sheared
• Position of bolt heads not always fixed
• Vehicle bodywork may be distorted
• Vehicle may be crash damaged
• Weight of battery
• Removal of wiring looms tricky
• Manipulation of connectors (especially where locking tabs fitted)
• High voltages until wiring loom/module links removed
• Lack of data on module condition in many electric-vehicle batteries
• Lack of labelling and identifying marks
• Potential fire hazards
• Potential offgassing of HF
• Variety of vehicle shapes and sizes
• Different pack configurations and locations
• Different fixings and tooling required
• Bus bars
• Electronics
• Wiring looms
• Modules > Cells
• Other components
Recovered components
• Clean separation of anodes and cathode for direct recycling difficult
• Very finely powdered materials present risks (nanoparticles)
• Potential for HF compounds formed from electrolyte
• Potential for thermal effects if cells shorted during disassembly
• Chemistries not always known or may be proprietary
• Additional challenges with cylindrical cells (unwinding spiral)
• Sealants may be used in module manufacture (difficult to remove)
• Cells stuck together in modules with adhesives (difficult to separate)
• Components may be soldered together (difficult to separate)
• Module state of charge may not be known
• Casings
• Terminals
• Cells
Pack removal
Disassembly problems
Recovered components
Recovered materials
(depending on cell chemistry
and recycling process)
• Cobalt
• Nickel
• Lithium
• Graphite
• Manganese
• Aluminium
• Plastics
Fig. 4 | Diag ram showing ch allenges of d isassem bly at differ ent levels of
scale. Electr ic-vehicle batte ry packs are co mplex in design, c ontaining wi ring
looms, bus bars, electronics, modules, cells and other components. There are
also many dif ferent type s of fixture s and fastenin gs, including sc rews, bolts,
adhesives , sealants and s olders, which are n ot designed for r obotic removal.
80 | Nature | Vol 575 | 7 November 2019
Review

copper can reprecipitate throughout the cell, increasing the risks of
short-circuiting and thermal runaway.
Current LIB-processing technologies essentially bypass these
concerns by feeding end-of-life batteries directly into a shredder or
high-temperature reactor. Industrial comminution technologies can
passivate batteries directly but recovered battery materials then require
a complex set of physical and chemical processes to produce usable
materials streams. Pyrometallurgical recycling processes (see section
‘Stabilization and passivation of end-of-life batteries’) at scale may be
able to accept entire electric-vehicle modules without further disas-
sembly. However, this solution fails to capture much of the embodied
energy that goes into LIB manufacture, and leaves chemical separation
techniques with much to do as the battery materials become ever more
intimately mixed.
Recycling methods
Pyrometallurgical recovery
Pyrometallurgical metals reclamation uses a high-temperature furnace
to reduce the component metal oxides to an alloy of Co, Cu, Fe and Ni.
The high temperatures involved mean that the batteries are ‘smelted’,
and the process, which is a natural progression from those used for other
types of batteries, is already established commercially for consumer
LIBs. It is particularly advantageous for the recycling of general con-
sumer LIBs, which currently tends to be geared towards an imperfectly
sorted feedstock of cells (indeed, the batteries can be processed along
with other types of waste to improve the thermodynamics and products
obtained), and this versatility is also valuable with respect to electric-
vehicle LIBs. As the metal current collectors aid the smelting process
56
,
the technique has the important advantage that it can be used with
whole cells or modules, without the need for a prior passivation step.
The products of the pyrometallurgical process are a metallic alloy
fraction, slag and gases. The gaseous products produced at lower tem-
peratures (<150 °C) comprise volatile organics from the electrolyte and
binder components. At higher temperatures the polymers decompose
and burn off. The metal alloy can be separated through hydrometallur-
gical processes (see section ‘Hydrometallurgical metals reclamation’)
into the component metals, and the slag typically contains the metals
aluminium, manganese and lithium, which can be reclaimed by further
hydrometallurgical processing, but can alternatively be used in other
industries such as the cement industry. There is relatively little safety
risk in this process, as the cells and modules are all taken to extreme
temperatures with a reductant for metal reclamation—aluminium from
the electrode foils and packaging is a major contributor here—so the
hazards are contained within the processing. In addition, the burning of
the electrolytes and plastics is exothermic and reduce the energy con-
sumption required for the process. It follows that in the pyrometallurgi-
cal process there is typically no consideration given to the reclamation
of the electrolytes and the plastics (approximately 40–50 per cent of the
battery weight) or othercomponents such as the lithium salts. Despite
environmental drawbacks (such as the production of toxic gases, which
must be captured or remediated and the requirement for hydrometal-
lurgical post-processing), high energy costs, and the limited number
of materials reclaimed, this remains a frequently used process for the
extraction of high-value transition metals such as cobalt and nickel57.
Physical materials separation
For reclamation after comminution, recovered materials can be sub-
jected to a range of physical separation processes that exploit variations
in properties such as particle size, density, ferromagnetism and hydro-
phobicity. These processes include sieves, filters, magnets, shaker tables
and heavy media, used to separate a mixture of lithium-rich solution, low-
density plastics and papers, magnetic casings, coated electrodes and
electrode powders. The result is generally a concentration of electrode
coatings in the fine fractions of material, and a concentration of plastics,
casing materials, and metal foils in the coarse fractions
58
. The coarse
fractions can be put through magnetic separation processes to remove
magnetic material such as steel casings and density separation pro-
cesses to separate plastics from foils. The fine product is referred to as
the ‘black mass’, and comprises the electrode coatings (metal oxides
and carbon). The carbon can be separated from metal oxides by froth
flotation, which exploits the hydrophobicity of carbon to separate it
from the more hydrophilic metal oxides59. An overview of how these pro-
cesses are used by several companies is shown in Fig.5, which mentions
the Recupyl8 (France), Akkuser49 (Finland), Duesenfeld50 (Germany)
and Retriev51 (USA/ Canada) processes.
Often, the polymeric binders from the ‘black mass’ components need
to be eliminated to liberate the graphite and metal oxides from the cop-
per and aluminium current collectors. Published routes include the
use of sonication in a solvent such as N-methyl-2-pyrrolidone (NMP)
or dimethylformamide (DMF) to detach the cathode from the current
collector
60
, thermal heat treatment to decompose the binder
61,62
, or dis-
solution of the aluminium current collector63. These processes, however,
often require high temperatures (60–100 °C) and are relatively slow
(3h). While ultrasound can induce faster delamination (1.5h), this is
still too slow for a continuous-flow process and the required solvent-
to-solid mass ratios of 10:1 will not be viable on a commercial scale with
these solvents64.
Recent teardowns of cells indicate that manufacturers are transition-
ing away from fluorinated binders. Many newer batteries are moving
toward alternative binders on the anode, such as carboxymethyl cel-
lulose (CMC), which is water-soluble, and styrene butadiene rubber
(SBR), which is not water-soluble but is applied as an emulsion that may
be easier to remove at end-of-life. There is also work on water-based
binder systems for cathodes, but this is proving to be more challenging.
Other studies have used cellulose- and lignin-based binders, although
many of these are still in the laboratory testing phase65.
Hydrometallurgical metals reclamation
Hydrometallurgical treatments involve the use of aqueous solutions to
leach the desired metals from cathode material. By far the most common
combination of reagents reported is H2SO4/H2O2 (ref. 66). A number of
studies have been carried out in order to determine the most efficient
set of conditions to achieve an optimal leaching rate. These include:
concentration of leaching acid, time, temperature of solution, the solid-
to-liquid ratio and the addition of a reducing agent67. In most of these
studies, it was found that leaching efficiency improved when H2O2 was
added. Somewhat counterintuitively, it is understood that H
2
O
2
acts
as a reducing agent to convert insoluble Co(III) materials into soluble
Co(II) through the reaction7:
2LiCoO (s)+3H SO +H O→2CoSO(aq)+Li SO +4HO+O
22422424 22
A range of other possible leaching acids and reducing agents have
been investigated
68–72
. The leached solution may also subsequently
be treated with an organic solvent to perform a solvent extraction
73–75
.
Once leached, the metals may be recovered through a number of pre-
cipitation reactions controlled by manipulating the pH of the solution.
Cobalt is usually extracted either as the sulfate, oxalate, hydroxide or
carbonate75–79, and then lithium can be extracted through a precipitation
reaction forming Li
2
CO
3
or Li
3
PO
480,81
. An alternative recycling method
describes mechanochemical treatment of materials, where electrode
materials are ground with a chlorine compound or complexing agent
to produce water-soluble salts of cobalt, which can be separated from
insoluble fractions by washing with water82,83.
Most current recycling processes fall under the umbrella of ‘reagent
recovery’ because the materials, with sufficient purity, can be re-used
not just for resynthesizing the original cathode materials, but also in a
range of other applications, such as the synthesis of CoFe
2
O
4
orMnCo
2
O
4
(refs. 84–86). Following initial work focused on the leaching and
Nature | Vol 575 | 7 November 2019 | 81

remanufacture of LiCoO2 (ref. 87), work has since moved on to strate-
gies for new cell chemistries, which typically contain multiple transition
metals (for example, LiNi1− x − yMnxCoyO2; NMC). In such cases, once the
metals have been leached from the cathode material, either sequential
precipitation is employed to recover the individual metals, or the direct
remanufacture of the cathode is targeted, such as work to recover NMC88.
In this work, after leaching the metals from the cathode, the concentra-
tions of the various metals in solution were measured and adjusted to
match those in the target material (1:1:1 Ni:Mn:Co for NMC-111). The same
group has applied the technique to NMC with varying metal contents and
successfully resynthesized such NMC materials through the production
of a precursor hydroxide, NixMnyCoz(OH)2 with x, y and z varying accord-
ing to the desiredfinal composition of the cathode89.
Other groups have published similar recovery methods with modifica-
tions such as additional solvent extraction steps
90
, lactic acid or urea as
an alternative to sulfuric acid (additionally facilitating resynthesis)
91,92
as
well as investigating the effect of magnesium in the resynthesized mate-
rial
93
. The big issues to be addressed with all solvo-metallurgical pro-
cesses are the volumes of solvents required, the speed of delamination,
the costs of neutralization and the likelihood of cross-contamination of
materials. Although shredding is a fast and efficient method of rendering
the battery materials safe, mixing the anode and cathode materials at
the start of the recycling process complicates downstream processing.
A method in which anode and cathode assemblies could be separated
prior to mechanical or solvent-based separation would greatly improve
material segregation. This is one of several key areas where designing
for end-of-life recycling promises to have a real impact, but the historic
backlog of batteries containing polyvinylidene fluoride (PVDF) as a
binder will still need to be processed. It is clear that the current design
of cells makes recycling extremely complex and neither hydro- nor
pyrometallurgy currently provides routes that lead to pure streams of
material that can easily be fed into a closed-loop system for batteries.
Direct recycling
The removal of cathode or anode material from the electrode for
reconditioning and re-use in a remanufactured LIB is known as direct
recycling. In principle, mixed metal-oxide cathode materials can be
reincorporated into a new cathode electrode with minimal changes to
the crystal morphology of the active material. In general, this will require
the lithium content to be replenished to compensate for losses due to
degradation of the material during battery use and because materials
may not be recovered from batteries in the fully discharged state with
the cathodes fully lithiated. So far, work in this area has focused primarily
on laptop and mobile phone batteries, as a result of the larger amounts
of these available for recycling
38
. An example of how this recycling route
could work has been outlined recently
94
. Cathode strips, obtained after
dismantling spent batteries, were soaked in NMP before undergoing
sonication. Powders were either regenerated through simple solid-state
synthesis with the addition of fresh Li
2
CO
3
or treated hydrothermally
with a solution containing LiOH/Li2SO4 before annealing.
For high-cobalt cathodes such as lithium cobalt oxide (LCO) conven-
tional pyrometallurgical (see section ‘Pyrometallurgical recovery’) or
Akkuser (Finland) Duesenfeld (Germany)
Recupyl (France) Retriev (USA)
Umicore (Belgium)
Water spray or
immersion
comminution
Opening
Physical
separation
Froth otation
Vacuum drying
Size
separation
Third-party
processor
Gas blanket
comminution
Density
separation
Magnetic
separation
Li recovery
Hydrolysis and
ltration
Hydrometallurgical
extraction
Material recovery
Slag
Alloy
Size
Separation
Dry thermal
processing
Ni, Co
Cu, Fe
Al, Li,
Mn
Pyrometallurgy
High-airow
comminution
Second
comminution
Batteries
Cathode
Anode
Anode and
cathode
coatings
Plastics Foils,
anode,
cathode
Steel
and
iron
Plastics
Foils
Foils,
anode,
cathode
Steel,
iron,
plastics,
foils
Li
solution
Electrolyte
Foils,
anode
Dry thermal
processing
Cathode Foils
Fig. 5 | Flow cha rt represe nting pote ntial routes fo r the circular e conomy of
LIBs, detailing second-use applications, re-use, physical recovery, chemical
recovery and biorecovery. A range of comm ercial entiti es have
commercia lized process es for recycling LI Bs. Differen t approaches for th e
physical se paration of bat teries and the r ecovery of mater ials are indicat ed.
82 | Nature | Vol 575 | 7 November 2019
Review

hydrometallurgical (see section ‘Hydrometallurgical recovery’) recy-
cling processes can recover around 70% of the cathode value11. However,
for other cathode chemistries that are not as cobalt-rich, this figure
drops notably11. A 2019 648-lb Nissan Leaf battery, for example, costs
US$6,500–8,500 new, but the value of the pure metals in the cathode
material is less than US$400 and the cost of the equivalent amount of
NMC (an alternative cathode material) is in the region of US$4,000. It
is important, therefore, to appreciate that cathode material must be
directly recycled (or upcycled) to recover sufficient value. As direct
recycling avoids lengthy and expensive purification steps, it could be
particularly advantageous for lower-value cathodes such as LiMn
2
O
4
and LiFePO4, where manufacturing of the cathode oxides is the major
contributor to cathode costs, embedded energy and carbon dioxide
footprint95.
Direct recycling also has the advantage that, in principle, all battery
components20 can be recovered and re-used after further processing
(with the exclusion of separators). Although there is substantial litera-
ture regarding the recycling of the cathode component from spent LIBs,
research on recycling of the graphitic anode is limited, owing to its lower
recovery value. Nevertheless, the successful re-use of mechanically
separated graphite anodes from spent batteries has been demonstrated,
with similar properties to that of pristine graphite96.
Despite the potential advantages of direct recycling, however, consid-
erable obstacles remain to be overcome before it can become a practical
reality. The efficiency of direct recycling processes is correlated with the
state of health of the battery and may not be advantageous where the
state of charge is low
97
. There are also potential issues with the flexibility
of these routes to handle metal oxides of different compositions. For
maximum efficiency, direct recycling processes must be tailored to spe-
cific cathode formulations, necessitating different processes for differ-
ent cathode materials
97
. The ten or so years spent in a vehicle—followed,
perhaps, by a few more in a second-use application—therefore present
a challenge in an industry where battery formulations are evolving at a
rapid pace. Direct recycling may struggle to accommodate feedstocks
of unknown or poorly characterized provenance, and there will be com-
mercial reluctance to re-use material if product quality is affected.
The direct recycling route for cathode coatings is also highly sensitive
to contamination by other metals, such as aluminium, which results in
poor electrochemical performance
60
. In particular, methods of recover-
ing materials for further physical or chemical separation that involve a
high degree of comminution form fine particles of Al and Cu, which are
difficult to separate from the electrode coatings. For this reason, pro-
cesses that do not mechanically stress the electrode foils are favoured
in direct recycling, and separation of the materials streams prior to
mechanical sorting is preferable. However, methods of removing the
electrode binder—typically pyrolysis or dissolution—present further
challenges, such as the production of hazardous byproducts such as
HF from pyrolysis of the PVDF binder or the use of the highly toxic
NMP as a solvent for dissolution. The potential for the undesirable
reaction of the PVDF binder with the electrode material appears to
be a notable omission in the recycling literature, despite a growing
body of research illustrating that PVDF is an excellent low-temperature
fluorinating reagent for metal oxides
98
. Furthermore, recent research
suggests that a certain degree of reaction can occur with the cathode
even under conditions of normal cell operation99.
Biological metals reclamation
Bioleaching, in which bacteria are harnessed to recover valuable met-
als, has been used successfully in the mining industry
100,101
. This is an
emerging technology for LIB recycling and metal reclamation and is
potentially complementary to the hydrometallurgical and pyromet-
allurgical processes currently used for metal extraction
102,103
; cobalt
and nickel, in particular, are difficult to separate and require additional
solvent-extraction steps. The process uses microorganisms to digest
metal oxides from the cathode selectively
104
and to reduce these oxides
to produce metal nanoparticles
105,106
. The number of studies that have
been performed thus far, however, is relatively small and there is plenty
of opportunity for further investigation in this field. The recycling meth-
ods discussed are compared in Fig.6.
Summary and opportunities
The electric-vehicle revolution is set to change the automotive industry
radically, and some of the most profound changes will inevitably relate
to the management and decommissioning of vehicles at end-of-life. Of
chief concern are the complex, high-tech power trains and, in particular,
the LIBs. To put this into perspective, electrification of only 2% of the
current global car fleet would represent a line of cars—and in due course,
of end-of-life waste—that could stretch around the Earth. There is wide
acceptance that, for environmental and safety reasons, stockpiling (or
worse, landfill) and wholesale transport of end-of-life electric-vehicle
batteries are not attractive options, and that the management of end-
of-life electric-vehicle waste will require regional solutions.
In the waste management hierarchy, re-use is considered preferable
to recycling, in order to extract maximum economic value and minimize
environmental impacts. Many companies in various parts of the world
are already piloting the second use of electric-vehicle LIBs for a range
of energy storage applications. Advanced sensors and improved meth-
ods of monitoring batteries in the field and end-of-life testing would
enable the characteristics of individual end-of-life batteries to be bet-
ter matched to proposed second-use applications, with concomitant
advantages in lifetime, safety and market value. Even if all the benefits of
Comparison of different LiB recycling methods
Complexity Capital cost Production cost
Pyrometallurgy
Hydrometallurgy
Direct recycling
Pyr
ometallurgy
Hydr
ometallurgy
Dir
ect recycling
Best Worst
No
No No
No No
Cathode
morphology
preserved
Material
suitable for
direct re-use Cobalt
recovered
Nickel
recovered
Technology
readiness
Quality of
recovered
material
Quantity of
recovered
material
Waste
generation Energy usage
Presorting of
batteries
required Copper
recovered
Manganese
recovered
Aluminium
recovered
Lithium
recovered
Fig. 6 | Compa rison of dif ferent LiB re cycling metho ds.
Nature | Vol 575 | 7 November 2019 | 83

second-use are realized, however, it must be remembered that recycling
(if not landfill) is the inevitable fate of all batteries.
Some recent life-cycle analyses has indicated that the application of
current recycling processes to the present generation of electric-vehicle
LIBs may not in all cases result in reductions in greenhouse gas emis-
sions compared to primary production
107
. More efficient processes are
urgently needed to improve both the environmental and economic
viability of recycling, which at present is heavily dependent on cobalt
content. However, as the amount of cobalt in cathodes is reduced for
economicand other reasons, to recycleusing current methods will become
less advantageous owing to the lower value of the materials recovered.
At present, there are low volumes of electric-vehicle batteries that
require recycling. As these volumes increase dramatically, there are
questions concerning the economies (and diseconomies) of scale in
relation to recycling operations
58
. Pyrometallurgical routes, in par-
ticular, suffer from high capital costs, and if full recyclability of LIBs is
to be achieved, alternative methods are urgently required, rather than
seeking to recycle only the most economically valuable components.
There are a number of lessons that the future LIB recycling industry
could learn from the highly successful lead–acid battery recycling indus-
try. As a technology, lead–acid batteries are relatively standardized and
simple to disassemble and recycle, which minimizes costs, allowing the
value of lead to drive recycling. Unfortunately, for a rapidly developing
technology such as electric-vehicle LIBs, such advantages are not likely
to apply any time soon.
A number of improvements could make electric-vehicle LIB recycling
processes economically more efficient23, such as better sorting tech-
nologies, a method for separating electrode materials, greater process
flexibility, design for recycling, and greater manufacturer standardiza-
tion of batteries. There is a clear opportunity for a more sophisticated
approach to battery recovery through automated disassembly, smart
segregation of different batteries and the intelligent characterization,
evaluation and ‘triage’ of used batteries into streams for remanufacture,
re-use and recycling. The potential benefits of this are many and include
reduced costs, higher value of recovered material streams, and the near
elimination of the risk of harm to human workers.
The design of current battery packs is not optimized for easy disassem-
bly. Use of adhesives, bonding methods and fixtures do not lend them-
selves to easy deconstruction either by hand or machine. All reported
current commercial physical cell-breaking processes employ shredding
or milling with subsequent sorting of the component materials. This
makes the separation of the components more difficult than if they
were presorted and considerably reduces the economic value of waste
material streams. Many of the challenges this presents to remanufac-
ture, re-use and recycling could be addressed if considered early in the
design process.
For direct recycling where purity of the recovered materials is
required, a process which involves less component contamination dur
-
ing the breaking stage is important. This would benefit from an analysis
of the cell component chemistries, and the state of charge and state of
health of the cells before disassembly into the component parts, rather
than the production of a mixture of all components. At present, this sepa-
ration has only been performed at a laboratory scale and usually employs
manual disassembly methods that are difficult to scale up economically.
The move to greater automation and robotic disassembly promises to
overcome some of these hurdles. Issues regarding the binder still need
to be resolved, and acid, alkali, solvent and thermal treatments all have
their positives and negatives. A cell design for reclamation of materials
is extremely appealing, with low-cost water-soluble binders.
We have focused here on the scientific challenges of recycling LIBs,
but we recognize that the ‘system performance’ of the LIB recycling
industry will be strongly affected by a range of non-technical factors,
such as the nature of the collection, transportation, storage and logis-
tics of LIBs at the end-of-life. As these vary from country to country
and region to region, it follows that different jurisdictions may arrive
at different answers to the problems posed.Research is under way
in the Faraday Institution ReLiB Project, UK; the ReCell Project, US; at
CSIRO in Australia and at a number of European Union projects includ-
ing ReLieVe, Lithorec and AmplifII.
Recycling electric-vehicle batteries at end-of-life is essential for many
reasons. At present there is little hope that profitable processes will be
found for all types of current and future types of electric-vehicle LIBs
without substantial successful research and development, so the impera-
tive to recycle will derive primarily from the desire to avoid landfill and
to secure the supply of strategic elements. The environmental and eco-
nomic advantages of second-use and the low volume of electric-vehicle
batteries currently available for recycling could stifle the development
of a recycling industry in some places. In many nations, the elements
and materials contained in the batteries are not available, and access to
resources is crucial in ensuring a stable supply chain. Electric vehicles
may prove to be a valuable secondary resource for critical materials.
Careful husbandry of the resources consumed by electric-vehicle battery
manufacturing—and recycling—surely hold the key to the sustainability
of the future automotive industry.
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Acknowledgements Many of the ideas suggested for recovery of high-value materials will be
trialled by the Faraday Institution’s ReLiB fast-start project funded by the Faraday Institution
(grant numbers FIRG005 and FIRG006) and by the ReCell Center, at Argonne National
Laboratory, funded by the US Department of Energy. We acknowledge the contribution to the
creation of the ReLiB project of N. Rowson (Birmingham Centre for Strategic Elements and
Critical Materials). We also thank Q. Dai at Argonne National Laboratories for providing
additional data for Fig. 6.
Author contributions G.H. and P.A. produced the original concept of the Review, and wrote
the article, integrating contributions from the team and editing and shaping the review. G.H.
produced the ‘Social and environmental impacts of LIBs’ section. R.Somerville and E.K.
collaborated on the ‘Physical materials separation’ and ‘Stabilization andpassivationof end-of-
life batteries’ sections; E.K. produced the ‘Biological recovery’ section. L.D. and P.S. produced
the ‘Direct recycling’ section and part of the ‘Hydrometallurgical metals reclamation’ section.
R.Stolkin and A.W. collaboratively produced the ‘Automating battery assembly’ section. P.C.
provided contributions on safety, and safe discharging of batteries, O.H. contributed to the
supply and value chain, environmental impact and economic assessments and S.L. provided
information on battery re-use. A.A. and K.R. produced most of the ‘Hydrometallurgical metals
reclamation’ section. L.G. critically revised the article. Figures 1 and 2 were created by G.H.
(with help from R.Somerville and E.K.) and Fig. 4 was created by R.Somerville. Figure 3 was
created by L.D., P.A. and G.H. and Fig. 6 was created by G.H. and L.G.
Competing interests The authors declare no competing interests.
Additional information
Correspondence and requests for materials should be addressed to G.H. or P.A.
Peer review information Nature thanks Anand Bhatt and Matthew Lacey and the other,
anonymous, reviewer(s) for their contribution to the peer review of this work.
Reprints and permissions information is available at http://www.nature.com/reprints.
Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in
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