Oleg Borodin

Army Research Laboratory | ALC · Adelphi Laboratory Center (ALC)

A new class of electrolytes has been reported, hybridizing aqueous with non-aqueous solvents, which combines the non-flammability and non-toxicity characteristics of aqueous electrolytes with the superior electrochemical stability of non-aqueous systems. Here we report measurements of the structure of an electrolyte composed of an equal-mass mixtur...

The ideal electrolyte for the widely used LiNi0.8Mn0.1Co0.1O2 (NMC811)||graphite lithium-ion batteries is expected to have the capability of supporting higher voltages (≥4.5 volts), fast charging (≤15 minutes), charging/discharging over a wide temperature range (±60 degrees Celsius) without lithium plating, and non-flammability1–4. No existing elec...

Rechargeable aqueous Zn metal batteries are promising systems for grid storage because of their high energy density, low cost, and non-flammability. However, Zn metal anodes have major limitations due to dendrite formation and concurrent water splitting during charge-discharge cycling. Both processes negatively affect coulombic efficiency (CE) and...

Rechargeable aqueous Zn metal batteries are promising systems for grid storage because of their high energy density, low cost, and non-flammability. However, Zn metal anodes have major limitations due to dendrite formation and concurrent water splitting during charge-discharge cycling. Both processes negatively affect coulombic efficiency (CE) and...

Electrification of transportation and rising demand for grid energy storage continue to build momentum around batteries across the globe. However, the supply chain of Li-ion batteries is exposed to the increasing challenges of resourcing essential and scarce materials. Therefore, incentives to develop more sustainable battery chemistries are growin...

Rechargeable aqueous Zn metal batteries are promising systems for grid storage because of their high energy density, low cost, and non-flammability. However, Zn metal anodes have major limitations due to...

Supramolecular frameworks have been widely synthesized for ion transport applications. However, conventional approaches of constructing ion transport pathways in supramolecular frameworks typically require complex processes and display poor scalability, high cost, and limited sustainability. Here, we report the scalable and cost-effective synthesis...

Lithium halide cathodes potentially offer a high energy density at a low cost for rechargeable batteries. However, these cathodes suffer from quick capacity decay in organic electrolytes, and the failure mechanism remains elusive. Here, we report that liquefying the halogen or interhalogen compounds is a prerequisite for achieving high reversibilit...

The transitions to electric vehicles and renewable power sources are not only a change of personal lifestyles but also tactical approaches to a sustainable future for us and our offspring, in which the energy supply will no longer be at the expense of natural resource depletion and environmental damage. The cornerstones of this sensational transiti...

Extensive efforts have been made to seek new battery chemistries based on multivalent working ions, with the aim to replace the mature lithium-ion batteries. These efforts were initially driven by the pursuit of higher capacity/energy, better safety and lower cost, and more recently have significantly intensified with the increasing concerns over t...

High energy density, improved safety, temperature resilience and sustainability are desirable properties for lithium battery electrolytes, yet these metrics are rarely achieved simultaneously. Inspired by the compositions of clean fire extinguishing agents, we demonstrate inherently safe liquefied gas electrolytes (LGE) based on 1,1,1,2-tetrafluoro...

The water-in-salt concept has significantly improved the electrochemical stability of aqueous electrolytes, and the hybridization with organic solvents or ionic liquids has further enhanced their reductive stability. [1] Here, we open a large design space by introducing succinonitrile as a cosolvent in water/ionic liquid/succinonitrile hybrid elect...

Modern electrolytes of the omnipresent lithium-ion batteries (LIBs) have for more than 25 years been based upon 1 M LiPF6 in a 50:50 EC:DMC mixture, commonly known as LP30. The success of the basic design of the LP30 electrolyte, with many variations and additions made over the years, is unchallenged. Yet, some molecular level fundamentals of LP30...

The rechargeability of aqueous zinc metal batteries is plagued by parasitic reactions of the zinc metal anode and detrimental morphologies such as dendritic or dead zinc. To improve the zinc metal reversibility, hereby we report a new solution structure of aqueous electrolyte with hydroxyl-ion scavengers and hydrophobicity localized in solvent clus...

Rechargeable magnesium (Mg) and calcium (Ca) metal batteries (RMBs and RCBs) are promising alternatives to lithium (Li)-ion batteries due to their significantly higher crustal abundance and energy density. However, RMBs and RCBs are still plagued by high overpotentials associated with parasitic reactions and sluggish kinetics resulting from strong...

LiNi x Co y Mn z O 2 (x+y+z=1)||graphite lithium‐ion battery (LIB) chemistry promises practical applications. However, its low‐ temperature (≤ ‐20 o C) performance is poor because the increased resistance encountered by Li + transport in and across the bulk electrolytes and the electrolyte/electrode interphases induces capacity loss and battery fai...

LiNi x Co y Mn z O 2 (x+y+z=1)||graphite lithium‐ion battery (LIB) chemistry promises practical applications. However, its low‐ temperature (≤ ‐20 o C) performance is poor because the increased resistance encountered by Li + transport in and across the bulk electrolytes and the electrolyte/electrode interphases induces capacity loss and battery fai...

Rechargeable Zn metal batteries (RZMBs) may provide a more sustainable and lower-cost alternative to established battery technologies in meeting energy storage applications of the future. However, the most promising electrolytes for RZMBs are generally aqueous and require high concentrations of salt(s) to bring efficiencies toward commercially viab...

High-energy density, improved safety, temperature resilience and sustainability are desirable properties for lithium-battery electrolytes, yet these metrics are rarely achieved simultaneously. Inspired by the compositions of clean fire-extinguishing agents, we demonstrate inherently safe liquefied gas electrolytes based on 1,1,1,2-tetrafluoroethane...

Raman spectroscopy is widely used to evaluate the ionic interactions and solvates present in electrolytes. As shown here, however, Raman spectra for crystalline solvates containing the lithium bis(trifluoromethanesulfonyl)imide (or amide) (i.e., LiN(SO2CF3)2, LiTFSI, LiTFSA, LiNTf2 or LiTf2N) salt indicate that the commonly used vibrational band an...

The water‐in‐salt concept has significantly improved the electrochemical stability of aqueous electrolytes, and the hybridization with organic solvents or ionic liquids has further enhanced their reductive stability, enabling cell chemistries with up to 150 Wh kg−1 of active material. Here, a large design space is opened by introducing succinonitri...

The development of high safety lithium‐ion batteries (LIBs) is greatly impeded by the flammability and leakage concerns of typical organic solvent‐based electrolytes. As one of the alternative classes of electrolytes, hydrogel electrolytes exhibit high safety, high flexibility, low cost, and are benign to the environment. However, the narrow electr...

Aqueous aluminum (Al) batteries are posited to be a cheap and energy dense alternative to conventional Li-ion chemistries, but an aqueous electrolyte mediating trivalent aluminum cations (Al³⁺) warrants greater scrutiny. This study provides a rigorous examination of aqueous Al electrolytes, with the first compelling evidence for a dynamic octahedra...

We report a systematic diffraction study of two "water-in-salt" electrolytes and a "water-in-bisalt" electrolyte combining high-energy X-ray diffraction (HEXRD) with polarized and unpolarized neutron diffraction (ND) on both H2O and D2O solutions. The measurements provide three independent combinations of correlations between the different pairs of...

Aqueous rechargeable Zn metal batteries (RZMBs) are promising candidates for coupling with intermittent renewable energy sources to realize a carbon-neutral energy transition. However, irreversible issues of Zn metal anodes and a poor understanding of the interphasial chemistry severely limit the viability of RZMBs. Here, we demonstrate that the ad...

In ionic-liquid (IL)-based electrolytes, relevant for current energy storage applications, ion transport is limited by strong ion–ion correlations, generally yielding inverse Haven ratios (ionicities) of below 1. In particular, Li is transported in anionic clusters into the wrong direction of the electric field, requiring compensation by diffusive...

The formation of solid-electrolyte interphase (SEI) in “water-in-salt” electrolyte (WiSE) expands the electrochemical stability window of aqueous electrolytes beyond 3.0 V. However, the parasitic hydrogen evolution reaction that drives anode corrosion, cracking, and the subsequent reformation of SEI still occurs, compromising long-term cycling perf...

Despite strong interest in replacing the flammable non-aqueous electrolytes with an aqueous alternative, the state-of-the-art aqueous electrolytes face challenges in achieving wide electrochemical stability window (ESW) and simultaneously maintaining fast ion-transport at sub-zero temperatures. Here, we proposed a non-flammable hybrid electrolyte c...

The practical applications of rechargeable zinc metal batteries are prevented by poor Zn reversibility, which induces both inferior Coulombic efficiency (CE) and zinc dendrite growth that worsens at low temperatures because of deteriorated kinetics in both charge and mass transfer. Herein, a liquefied gas electrolyte based on a mixture of fluoromet...

With the increasing interest in highly concentrated electrolyte systems, correct determination of the cation transference number is important. Pulsed‐field‐gradient (pfg) NMR technique, which measures self‐diffusion coefficients, is often applied on liquid electrolytes because of the wide accessibility and simple sample preparation. However, since...

Efficient, rechargeable Mg and Ca batteries Divalent rechargeable metal batteries such as those based on magnesium and calcium are of interest because of the abundance of these elements and their lower tendency to form dendrites, but practical demonstrations are lacking. Hou et al . used methoxyethyl amine chelants in which the ligands attach to th...

The solid electrolyte interphase (SEI) is an integral part of Li-ion batteries and their performance, representing the key enabler for reversibility and also serving as a major source of capacity loss and dictating the cell kinetics. In the pervasive LiPF6-containing electrolytes, LiF is one of the SEI’s major components; however, its formation mec...

Metallic zinc is an ideal anode due to its high theoretical capacity (820 mAh g−1), low redox potential (−0.762 V versus the standard hydrogen electrode), high abundance and low toxicity. When used in aqueous electrolyte, it also brings intrinsic safety, but suffers from severe irreversibility. This is best exemplified by low coulombic efficiency,...

The introduction of “water‐in‐salt” electrolyte (WiSE) concept opens a new horizon to aqueous electrochemistry that is benefited from the formation of a solid‐electrolyte interphase (SEI). However, such SEI still faces multiple challenges, including dissolution, mechanical damaging, and incessant reforming, which result in poor cycling stability. H...

The introduction of “water‐in‐salt” electrolyte (WiSE) concept opens a new horizon to aqueous electrochemistry that is benefited from the formation of a solid‐electrolyte interphase (SEI). However, such SEI still faces multiple challenges, including dissolution, mechanical damaging, and incessant reforming, which result in poor cycling stability. H...

Lithium batteries with Si, Al or Bi microsized (>10 µm) particle anodes promise a high capacity, ease of production, low cost and low environmental impact, yet they suffer from fast degradation and a low Coulombic efficiency. Here we demonstrate that a rationally designed electrolyte (2.0 M LiPF6 in 1:1 v/v mixture of tetrahydrofuran and 2-methylte...

In this presentation I will update on the recent progress towards obtaining fundamental understanding and improving three classes of electrolytes: 1) aqueous and hybrid electrolytes for lithium ion batteries including superconcentrated electrolytes; 2) non-aqueous electrolytes and their interaction with the electrodes for high energy density lithiu...

A comprehensive understanding of the solid–electrolyte interphase (SEI) composition is crucial to developing high-energy batteries based on lithium metal anodes. A particularly contentious issue concerns the presence of LiH in the SEI. Here we report on the use of synchrotron-based X-ray diffraction and pair distribution function analysis to identi...

Development of safe electrolytes that are compatible with both lithium metal anodes and high-voltage cathodes that can operate in a wide-temperature range is a formidable, yet important challenge. Recently, a new class of electrolytes based on liquefied gas solvents has shown promise in addressing this issue. Concerns, however, have been raised on...

Widespread commercial adoption of polymer electrolytes for lithium-ion batteries has been hindered by subpar transport properties, namely, ionic conductivities of <1 mS/cm at room temperature and slower Li+ compared to anion transport. The developed polymer and water-in-salt electrolyte demonstrated preferential Li+ transport compared to the anion...

Aqueous rechargeable zinc metal batteries promise attractive advantages including safety, high volumetric energy density and low cost; however, such benefits cannot be unlocked unless Zn reversibility meets stringent commercial viability. Herein, we report remarkable improvements on Zn reversibility in aqueous electrolytes when phosphonium-based ca...

The addition of phosphonium-based supporting salts and a subtle difference in their ligand chemistry remarkably improves the reversibility of aqueous Zn electrolytes. By promoting interphase formation, P444(2O1)-TFSI supports a Zn coulombic efficiency above 99 % even at 1.17 mA cm⁻² with 20 % Zn utilization per cycle, and a stable Zn∥Na2V6O16⋅1.63...

Predictive and quantitative understanding of ion and mass transport in liquid and polymeric electrolytes is at the heart of electrochemistry. Here, the goal is to accurately simulate the performance of an electrochemical cell, for which the temperature- and concentration-dependent transport coefficients of a given electrolyte, as well as the thermo...

Due to the low potentials on anode materials in lithium-ion batteries, the electrolyte decomposes on the anode forming a passivation layer, termed solid electrolyte interphase (SEI). The SEI plays an essential role in battery performance since it is a major source of capacity loss and dictates cell kinetics. Nevertheless, the properties of the SEI...

High-voltage cathodes (> 4.5 V) are key components of next-generation Lithium-ion batteries (NG-LIBs). However, their full potential has been hampered by limited knowledge of the underlying chemistry and physics of the buried cathode/electrolyte interface. In particular, the stabilization of the cathode surface under highly oxidizing potentials is...

Insight into Aqueous and Non-Aqueous Electrolyte Structure, Transport and Interfacial Properties from Molecular Modeling A molecular scale insight into ion transport and decomposition is important for understanding deficiencies of the currently used aqueous and non-aqueous electrolytes. In this presentation I will summarize progress made towards im...

Li metal, with the lowest thermodynamically achievable negative electrochemical potential and the highest specific capacity (3860 mAh g ⁻¹ ), is the ultimate anode choice for Li batteries. However, the highest reported Li plating/stripping Coulombic efficiency (CE) of 99.5% after extensive efforts is still too low for the Li metal-free (all the Li...

The electric double layer (EDL) is the ion arrangement evolving at electrolyte interfaces. Despite its importance in many applications such as super-capacitors, lithium ion batteries (LIB), water purification, and stabilization of nanoparticles in solution, the structural motifs of the EDL are still under debate. In LIB, the molecular scale ion arr...

With high energy density and improved safety, rechargeable battery chemistries with a zinc (Zn) metal anode offer promising and sustainable alternatives to those based on lithium metal or lithium ion intercalation/alloying anode materials; however, the poor electrochemical reversibility of Zn plating/stripping, induced by parasitic reactions with b...

Predictive knowledge of ion transport in electrolytes which bridges microscopic and macroscopic length scales is imperative to design new ion conductors and to simulate device performance. Here, we employed a novel approach combining operando X-ray photon correlation spectroscopy, X-ray absorption microscopy, continuum modelling, and molecular dyna...

Using synchrotron X‐rays the LiTFSI/H2O electrolyte interfacial decomposition pathways in the „water‐in‐salt“ and „salt‐in‐water“ regimes are investigated. The resultant photoelectron‐induced reduction was revealed to be concentration‐dependent interfacial chemistry that only occurs among closely contact ion‐pairs, which constitutes the rationale b...

Super‐concentrated “water‐in‐salt” electrolytes recently spurred resurgent interest for high energy density aqueous lithium‐ion batteries. Thermodynamic stabilization at high concentrations and kinetic barriers towards interfacial water electrolysis significantly expand the electrochemical stability window, facilitating high voltage aqueous cells....

“Water-in-salt” (WIS) and “water-in-bisalt” (WIBS) electrolytes have recently been developed for Li-ion batteries, combining the safety and environmental friendliness of aqueous electrolytes with a larger operating window made possible by a solid-electrolyte interphase. We report Quasielastic Neutron Scattering (QENS) measurements on solutions of a...

Rechargeable zinc metal batteries (RZMBs) offer a compelling complement to existing lithium ion and emerging lithium metal batteries for meeting the increasing energy storage demands of the future. Multiple recent reports have suggested that optimized electrolytes resolve a century-old challenge for RZMBs by achieving extremely reversible zinc plat...

Raman spectroscopy is a widely utilized method for determining information about the solvate species present in electrolyte solutions. Difficulties arise, however, when interpreting the Raman data in terms of correlating the spectroscopic vibrational bands with specific solvate species. Examples are provided to demonstrate how erroneous conclusions...

The momentum in developing next-generation high energy batteries calls for an electrolyte that is compatible with both lithium (Li) metal anode and high-voltage cathodes that is also capable of providing high power in a wide temperature range. Here, we present a fluoromethane-based liquefied gas electrolyte with acetonitrile cosolvent and higher, y...

A novel methylated pyrazole derivative, namely 1-methyl-3,5-bis(trifluoromethyl)-1H-pyrazole (MBTFMP) was synthesized for the first time and comprehensively characterized for high voltage application in lithium ion batteries (LIBs). The MBTFMP reactivity and performance was compared to the known 3,5-bis(trifluoromethyl)-1H-pyrazole (BTFMP) function...

Polysulfide shuttle effects, active material losses, formation of resistive surface layers and continuous electrolyte consumption create a major barrier for the lightweight and low-cost lithium-sulfur (Li-S) battery adoption. Tuning electrolyte composition by using additives and most importantly by substantially increasing electrolyte molarity was...

Lithium batteries with Si, Al or Bi microsized (>10 µm) particle anodes promise a high capacity, ease of production, low cost and low environmental impact, yet they suffer from fast degradation and a low Coulombic efficiency. Here we demonstrate that a rationally designed electrolyte (2.0 M LiPF6 in 1:1 v/v mixture of tetrahydrofuran and 2-methylte...

Among the several challenges to enable next-generation batteries is the development of an electrolyte which compatible with both lithium (Li) metal anode and high-voltage cathode at wide temperature range. Liquefied gas electrolytes with a new cosolvent and higher salt concentration show improved ionic conductivity of > 4 mS/cm at wide temperature...

Li metal, with the lowest thermodynamically achievable negative electrochemical potential and the highest specific capacity (3860 mAh g⁻¹), is the ultimate anode choice for Li batteries. However, the highest reported Li plating/stripping Coulombic efficiency (CE) of 99.5% after extensive efforts is still too low for the Li metal-free (all the Li me...

With high energy density and improved safety, rechargeable battery chemistries with a zinc (Zn) metal anode offer promising and sustainable alternatives to those based on lithium metal or lithium‐ion intercalation/alloying anode materials; however, the poor electrochemical reversibility of Zn plating/stripping, induced by parasitic reactions with b...

The solid–electrolyte interphase (SEI) dictates the performance of most batteries, but the understanding of its chemistry and structure is limited by the lack of in situ experimental tools. In this work, we present a dynamic picture of the SEI formation in lithium-ion batteries using in operando liquid secondary ion mass spectrometry in combination...

Water-in-salt electrolyte (WiSE) offers an electrochemical stability window much wider than typical aqueous electrolytes, but still falls short in accommodating high energy anode materials, mainly because of the enrichment of water molecules in the primary solvation sheath of Li+. Herein, we report a new strategy where a non-Li co-salt was introduc...

Coupling thin Li metal anodes with high-capacity/high-voltage cathodes such as LiNi0.8Co0.1Mn0.1O2 (NCM811) is a promising way to increase lithium battery energy density. Yet, the realization of high-performance full cells remains a formidable challenge. Here, we demonstrate a new class of highly coordinated, nonflammable carbonate electrolytes bas...