Michael Metzger

Dalhousie University | Dal · Department of Physics and Atmospheric Science

Lithium-ion batteries show various degradation phenomena during charge and discharge. In this thesis, we tackle the oxidative decomposition of battery components in high-voltage cells, and place a particular emphasis on gassing reactions and the role of contaminants. We employ On-line Electrochemical Mass Spectrometry, a novel technique for gas ana...

Layered LiNixMnyCozO2 (NMC) is a widely used class of cathode materials with LiNi1/3Mn1/3Co1/3O2 (NMC111) being the most common representative. However, Ni-rich NMCs are more and more in the focus of current research due to their higher specific capacity and energy. In this work we will compare LiNi1/3Mn1/3Co1/3O2 (NMC111), LiNi0.6Mn0.2Co0.2O2 (NMC...

To increase the energy density of lithium-ion batteries and to allow for longer driving ranges of battery electric vehicles, many research activities have been devoted to the development of near 5 V cathode materials, e.g., the LiMn1.5Ni0.5O4 spinel. However, the oxidative decomposition of conventional carbonate electrolytes as well as the instabil...

The lithium excess LixNi2-4x/3Sbx/3O2 (LNSO) materials were previously shown to demonstrate higher capacities and improved cyclability with increasing lithium content. While the performance trend is promising, observed capacities are much lower than theoretical capacities, pointing to a need for further understanding of active redox processes in th...

The anodic oxidation stability of battery components like the conductive carbon black (Super C65) and the co-solvent ethylene carbonate (EC) is of great relevance, especially with regards to high-voltage cathode materials. In this study, we use On-line Electrochemical Mass Spectrometry (OEMS) to deconvolute the CO and CO2 evolution from the anodic...

Prussian blue analogs, e.g., nickel hexacyanoferrate, NiFe(CN) 6 or NiHCF, are promising candidates as low-cost and high-rate intercalation materials for secondary batteries. 1–4 Recently, this material class has been shown to possess tremendous potential for a novel energy-efficient water desalination approach. 5–8 Rising water demands are exacerb...

Intercalative deionization (IDI) uses two cation intercalation electrodes separated by an anion exchange membrane in a symmetric cell design that has the potential to deliver electrochemically desalinated water in an energy- and water-efficient way. Here, we define and measure metrics to describe the performance and lifetime of IDI cells and compar...

Interfacial reactions in lithium‐ion batteries often involve gaseous reaction products. Mechanistic investigation of material degradation processes requires a technique to identify and quantify these gases in battery cells. On‐line electrochemical mass spectrometry (OEMS) is an operando gas analysis method that continuously samples the headspace of...

The heterogeneity of polymer electrolyte fuel cell catalyst degradation is studied under varied relative humidity and types of feed gas. Accelerated stress tests (ASTs) are performed on four membrane electrode assemblies (MEAs) under wet and dry conditions in an air or nitrogen environment for 30 000 square voltage cycles. The largest electrochemic...

Anode-free lithium metal batteries with liquid electrolytes could become a drop-in solution for making higher energy density and lower cost batteries with existing production facilities. Now, a synergistic approach is brought forward that bolsters the anode-free cells’ limited lithium inventory extending the cells’ cyclability.

For a battery cell, both the porosity of the electrodes/separator and the transport distance of charged species can evolve due to mechanical deformation arising from either lithium intercalation-induced swelling and contraction of the active particles or externally applied mechanical loading. To describe accurately the coupling between mechanical d...

The ever expanding mobile consumer electronic market has accelerated the need for safe and efficient fast‐charging approaches that improve the overall speed of battery charging without hastened deterioration of the battery performance. Herein, the impact of a resource inexpensive, physics‐based, electrochemically optimized fast‐charging algorithm (...

This reply provides updated energy consumption estimates at clearly defined separation conditions for electrochemical desalination concepts.

The anodic stability of conductive carbon and alkyl carbonate-based electrolyte solvents is a crucial requirement for the success of high-voltage lithium-ion cells, particularly at elevated temperatures. In order to quantify the oxidative stability of ethylene carbonate (EC), a critical component of lithium-ion battery electrolytes, and conductive...

Durability of cathode catalyst in polymer electrolyte fuel cells (PEFCs) is a key factor, limiting large-scale commercialization of PEFC for transportation applications. The catalyst degradation occurs during operational load profiles switches from ideal to peak, where multiple operational factors affect the degradation rate. The catalyst degrades...

With the rapid market increase of consumer electronic devices such as smartphones and tablets, the performance of lithium-ion batteries (LIBs) in such devices becomes an important factor. In particular, fast charging, longer lasting batteries and safety are primary concerns for consumers. Lithium cobalt oxide (LCO) is a common cathode material for...

For widespread commercialization of polymer electrolyte fuel cells (PEFCs), cost and durability need to be addressed. Reduction in cost should not negatively affect PEFC durability and performance. At high volume production, platinum (Pt) electro catalyst contributes to 41% of the total fuel cell stack cost for light duty vehicles. This cost contri...

In this contribution we will discuss our current understanding of the electrolyte oxidation mechanisms in lithium-ion batteries as well as of the various follow-up reactions that are triggered by electrolyte oxidation. Using online electrochemical mass spectrometry (OEMS) in combination with a two-compartment cell, in which a solid lithium ion cond...

Nickel-based cathode materials have become an exciting alternative to the widely used Li x CoO 2 (LCO) for consumer electronics. The main advantages of this type of cathode materials over the LCO electrodes are a higher practical capacity and excellent safety characteristics.[1] Additionally, the tendency to increase the nickel content of these ele...

With the U.S. Department of Energy (DOE) 2020 durability target for transportation applications of 5000 hours in mind [1], several studies have been performed to understand the factors influencing load cycle durability of the cathode catalyst layer subjected to various operating conditions. In general, high upper potential limit (> 1 V vs RHE), hig...

Desalination of brackish water sources is critical to addressing the growing global freshwater demand. One promising approach is electrically driven desalination using intercalation electrodes. While intercalation electrodes have been widely researched for energy storage applications, only a small subset of those materials is suitable for desalinat...

Nickel-based cathode materials have become an exciting alternative to the widely used Li x CoO 2 (LCO) for consumer electronics. The main advantages of this type of cathode materials over the LCO electrodes are a higher practical capacity and excellent safety characteristics.[1] Additionally, the tendency to increase the nickel content of these ele...

With the rapid market increase of consumer electronic devices such as smartphones and tablets, the performance of lithium-ion batteries in such devices becomes an important factor. In particular, fast charging, longer lasting batteries and safety are primary concerns for consumers. Lithium cobalt oxide (LCO) is a common cathode material for these a...

The structural integrity and chemical stability of layered Ni-rich oxide cathode materials are influential factors that critically affect the performance and reliability of lithium batteries. Prolonged battery operation often involves repeated phase transitions, buildup of mechanical stresses, which could result in chemical and mechanical changes i...

One known drawback of Ni-containing layered cathodes is their poor first cycle efficiency of 85%–90%, upon cycling in a practical potential window. The poor first cycle efficiency is likely a result of surface overlithiation due to significant lithium ion diffusion limitation at this bulk state of charge, but the overlithiation properties of Ni-con...

The impact of liquid electrolyte soaking on the interfacial resistance between garnet structured Li7La3Zr2O12 (LLZO) solid electrolyte and metallic lithium has been studied. Lithium carbonate (Li2CO3) formed by inadvertent exposure of LLZO to ambient conditions, is generally known to increase interfacial impedance and decrease lithium wettability....

We conduct a techno-economic analysis of electrochemical water deionization technologies. The objective of the analysis is to compare cost, volume, and energy consumption of membrane capacitive deionization (mCDI) to intercalative deionization techniques. Here, we first explore the concept of hybrid capacitive deionization (HCDI), i.e., a cation in...

In this study, the long-term chemothermal stability of chemically delithiated Li1Ni0.8Co0.15Al0.05O2 (NCA) was systematically investigated at relevant operating temperatures of polymer solid-state batteries using ex-situ synchrotron-based hard and soft X-ray absorption spectroscopy. The reduction of nickel on the surface, subsurface, and in the bul...

Presently, the challenges faced by batteries are twofold. Firstly, they are expected to possess high energy and power density for powering zero emission electric vehicles. Secondly, they are also expected to be inexpensive and safe for deployment in electric vehicles and consumer applications. A potential candidate ideally suited for this case are...

The structural integrity of layered Ni-rich oxide cathode materials are one of the most essential factors that critically affect the performance and reliability of lithium-ion batteries. Prolonged battery operation often involves repeated phase transitions, builds up mechanical stresses, and could provoke thermal spikes. Such sophisticated chemo-th...

The quality of metal oxide-based battery active materials is compromised by surface contamination from storage and handling at ambient conditions. We present a detailed analysis of the true nature and the quantity of the surface contaminants on two different cathode active materials, the widely used LiNi1/3Co1/3Mn1/3O2 (NCM111) and the Ni-rich LiNi...

Complex chemomechanical interplay exists over a wide range of length scales within the hierarchically structured lithium-ion battery. At the mesoscale, the interdependent structural complexity and chemical heterogeneity collectively govern the local chemistry and, as a result, critically influence the cell level performance. Here we investigate the...

The performance of metal oxide-based battery active materials is compromised by surface contaminants formed during storage and handling in ambient air. We present a detailed analysis of the true nature and the quantity of these surface contaminants on three different cathode active materials (CAMs), the widely used LiNi 1/3 Mn 1/3 Co 1/3 O 2 (NMC11...

The electrochemical oxidation of LiPF6-based electrolytes is reported to generate POF3 gas. In order to enable a quantitative analysis of the LiPF6 decomposition reactions, we aimed to establish calibration factors for POF3 and PF5 in on-line electrochemical mass spectrometry (OEMS). Thermal decomposition of dry LiPF6 is expected to yield PF5, but...

In this study, we compare the stability of alkyl carbonate electrolyte on NMC111, 622, 811, LNMO, and conductive carbon electrodes. We prove that CO2 and CO evolution onset potentials depend on the electrode material and increase in the order NMC811 < NMC111 ≈ NMC622 < conductive carbon ≈ LNMO, which we rationalize by two fundamentally different ox...

Recently, it was shown that H 2 O contamination in lithium-ion batteries can cause H 2 gassing during the formation of the solid-electrolyte interphase (SEI) on graphite as well as substantial concentrations of CO 2 in the battery cell. ¹ The latter was attributed to the hydrolysis of ethylene carbonate (EC) in the electrolyte by OH ⁻ formed throug...

Lithiumionenzellen zersetzen sich beim Laden und Entladen. Die Gasentwicklung dabei lässt sich mit elektrochemischer Massenspektrometrie verfolgen. Dafür gibt es eine Batterietestzelle mit separierten Elektrodenkompartments.

Li-Ion batteries have recently been used to power battery electric vehicles (BEVs). However, in order to penetrate the mass market, further improvements have to be achieved with respect to the driving range of BEVs. [1] The latter highly depends on the choice of the cathode active material, with layered lithium nickel manganese cobalt oxides (LiNi...

To develop reversible Li-O2 batteries, the need for novel carbon-free cathode materials is evident. In this study, we present the hydrothermal synthesis of highly conductive crystalline antimony doped tin oxide (ATO) nanoparticles, the fabrication of ATO electrodes with high surface area, and their application as cathodes in aprotic Li-O2 cells. We...

Apart from the often-described formation of interphases between the electrodes and the electrolyte in Li-ion batteries, changes of the bulk electrolyte also occur during cycling. In this study, we use On-line Electrochemical Mass Spectrometry (OEMS) to measure the gas evolution associated with changes in the electrolyte during the initial cycles of...

Recently, many research activities have been devoted to the development of near 5 V cathode materials, e.g. the LiMn1.5Ni0.5O4 spinel, in order to raise the energy density of lithium-ion batteries and to allow for longer driving ranges of battery electric vehicles. 1 However, the enhanced degradation of carbon and electrolyte by the use of these hi...

Lithium oxygen batteries (LOBs) are a very promising upcoming technology which however still suffers from low lifespan and dramatic capacities fading. Solid discharge products increase the contact resistance and block the electrochemically active electrodes. The resulting high oxidative potentials and formation of Li2CO3 due to electrolyte and carb...

In the emerging market of electric vehicles (EVs), the development of batteries with higher energy density and improved cycle-life is essential. ¹ Silicon-based anodes can significantly improve the energy density due to the huge specific capacity of ~3600 mAh/g Si , (corresponding to the Li 15 Si 4 phase ² ) which is roughly ten times larger compar...

Recently, many research activities have been devoted to the development of near 5 V cathode materials, e.g. the LiMn 1.5 Ni 0.5 O 4 spinel, in order to raise the energy density of lithium-ion batteries and to allow for longer driving ranges of battery electric vehicles. ¹ However, the enhanced degradation of carbon and electrolyte by the use of the...

Due to the uprising demand of energy storage in consumer electronics and electric vehicles, tremendous effort and interest have been drawn into the development of novel electrolyte additive blends in lithium-ion batteries (LIBs). However, the applications of LIBs have several critical limitations, including elevated temperature performance, calenda...

Gassing in lithium-ion batteries (LIBs) is a serious challenge, especially at high voltage and elevated temperature. In this study, we use On-line Electrochemical Mass Spectrometry (OEMS) and a two-compartment cell with a newly developed aluminum edge-seal to elucidate the origin of H2 evolution in LIBs. We demonstrate that the new sealing is entir...

This study deals with the decomposition of ethylene carbonate (EC) by H2O in the absence and presence of catalytically active hydroxide ions (OH- ) at reaction conditions close to lithium-ion battery operation. We use On-line Electrochemical Mass Spectrometry (OEMS) to quantify the CO2 evolved by these reactions, referred to as H2O-driven and OH-dr...

The electrolyte additive fluoroethylene carbonate (FEC) is known to significantly improve the lifetime of Li-ion batteries with silicon anodes. In this work, we show that FEC can indeed improve the lifetime of silicon-carbon composite anodes but is continuously consumed during electrochemical cycling. By the use of 19F-NMR spectroscopy and charge/d...

Carbon coatings on cathode materials with low electrical conductivity like phospho-olivines LiMPO 4 (M = 3d-transition metal) are known to improve their performance in Li-ion batteries. However, at high potentials and in the presence of water, the stability of carbon coatings on high-voltage materials (e.g., LiCoPO 4) may be limited due to the anod...

The gas evolution during the formation of graphite electrodes is quantified by On-line Electrochemical Mass Spectrometry (OEMS) for dry electrolyte (< 20 ppm H2O) and 4000 ppm H2O containing electrolyte to mimic the effect of trace water during the formation process. While the formation in dry electrolyte mainly shows ethylene (C2H4) from the reduc...

The gas evolution during the formation of graphite electrodes is quantified by On-line Electrochemical Mass Spectrometry (OEMS) for dry electrolyte (< 20 ppm H2O) and 4000 ppm H2O containing electrolyte to mimic the effect of trace water during the formation process. While the formation in dry electrolyte mainly shows ethylene (C2H4) from the reduc...

Recently, many investigations have been devoted to the development of novel electrolyte additives for Li-ion batteries. In carbonate-based electrolytes, most additives are reduced preferentially during the first charging cycle to generate a solid-electrolyte interphase (SEI) on the anode. ¹ Vinylene carbonate (VC) is the most widely investigated el...

The high reversibility of lithium ion batteries is largely related to the use of electrolyte components that form a solid-electrolyte interphase (SEI) on the anode, preventing further reduction of the bulk electrolyte but allowing reversible intercalation of Li-ions into graphite. Regarding SEI formation, ethylene carbonate (EC), vinylene carbonate...

Graphite is the most widely used anode material in Li-ion batteries due to its excellent lithium storage capability as well as long-term and cycle stability. Carbonate-based electrolytes are reduced on the graphite surface and form a solid electrolyte interface (SEI) within the first few cycles. The passivating layer inhibits continuous electrolyte...

The cycling performance, ex-situ surface analysis, and in-situ gas analysis of lithium ion batteries containing the widely used electrolyte additives VC and PS has been investigated. All of the electrolytes have good cycling performance at 25°C. However, the electrolytes containing additives have better discharge capacity retention and coulombic ef...

Lithium-ion coin cells containing electrolytes with and without 1, 3-propane sultone (PS) and vinylene carbonate (VC) have been prepared and investigated. The electrochemical performance of the cells is correlated with ex-situ surface analysis of the electrodes conducted by FTIR and XPS, and in-situ gas analysis by on-line electrochemical mass spec...

The cycling performance, ex-situ surface analysis, and in-situ gas analysis of lithium ion batteries containing the widely used electrolyte additives VC and PS has been investigated. All of the electrolytes have good cycling performance at 25°C. However, the electrolytes containing additives have better discharge capacity retention and coulombic ef...

Carbon coatings on cathode materials with low electrical conductivity like phospho-olivines LiMPO4 (M = 3d-transition metal) are known to improve their performance in Li-ion batteries. However, at high potentials and in the presence of water, the stability of carbon coatings on high-voltage materials (e.g., LiCoPO4) may be limited due to the anodic...

Aprotic Li-O-2 cells have attracted considerable research interest due to its outstandingly high theoretical specific capacity. However, published discharge capacities vary considerably among different researchers despite only minor differences in the tested cell components. Some research groups observe low discharge capacities and formation of pas...

Trimethylboroxine (TMB) is used as an additive in the electrolyte for improving the performance of LiCoPO4 (LCP) in Li-ion batteries. In this work, the role and behavior of TMB are investigated by cyclic voltammetry (CV), impedance spectroscopy (EIS) and on line electrochemical mass spectroscopy (OEMS). It was found that TMB oxidizes from 4.6 V and...

LiMPO4 (M=Fe, Co) materials are known as possible high voltage materials leading to high energy density batteries. LiFePO4 is electrochemically active below 4V vs. Li/Li+ with a theoretical capacity of 170 mAh/g, and it is well known for its good stability upon cycling [1]. Conversely, LiCoPO4, which works at higher potential (4.85 V), exhibits poo...

Li-O2cells are very promising energy conversion devices because of the theoretical specific capacity that they could provide (1). Unfortunately they are also very challenging regarding the instability of their components, like electrolyte solvent (2-4) and carbon electrode (5, 6) mostly due to the reactivity of superoxide ion radical during dischar...

Lithium-air batteries are one of the most promising future electric energy storage systems to power long range full electric vehicles due to the very large theoretical capacity of the oxygen cathode. Assuming Li2O2 as the main discharge product, a theoretical specific energy density of 2450 Wh per kg discharged cathode material can be gained compar...

Future Li-ion batteries are expected to reach high energy density by the use of high voltage cathode materials. At the high operating voltages (≥ 4.5 V vs. Li/Li+) most of the common alkyl carbonate electrolytes start to decompose followed by an evolution of gases upon cycling. In recent studies, Tsiouvaras et. al. and McCloskey et. al. showed that...

Future Li-ion batteries are expected to reach high energy density by the use of high voltage cathode materials. At the high operating voltages (≥ 4.5 V vs. Li/Li ⁺ ) most of the common alkyl carbonate electrolytes start to decompose followed by an evolution of gases upon cycling. In recent studies, Tsiouvaras et. al. and McCloskey et. al. showed th...

Lithium-air batteries are one of the most promising future electric energy storage systems to power long range full electric vehicles due to the very large theoretical capacity of the oxygen cathode. Assuming Li 2 O 2 as the main discharge product, a theoretical specific energy density of 2450 Wh per kg discharged cathode material can be gained com...