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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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DOE OSTI2024

Enabling High Stability of Co-Free LiNiO 2 Cathode via a Sulfide-Enriched Cathode Electrolyte Interface

Cobalt-free lithium nickel oxide (LNO) has garnered significant interest as the end member of high-nickel layered oxide cathodes for next-generation batteries. However, its practical performance notably underperforms expectations because of the structural degradation and unstable interfacial chemistry with electrolytes during cycling. Here, in this study, we report that a durable cathode-electrolyte interface (CEI), enriched by in situ formed sulfides and borides, can inhibit LNO structural degradation and suppress Ni ion dissolution. With the CEI protection, the stability of LNO can be remarkably extended, and batteries demonstrate a capacity retention rate of 84% (30 °C) and 79% (50 °C) after 200 cycles at 1C, respectively. These results demonstrate that enriching CEI with sulfur-containing species can effectively stabilize the interfacial chemistry of LNO, particularly at an elevated temperature of 50 °C. This finding provides valuable perspectives on designing electrolytes for cobalt-free LNO and other high-Ni cathodes toward the development of next-generation high-energy-density lithium-ion batteries.

25 ENERGY STORAGE↗
DOE OSTI2022

Next-Generation Cobalt-Free Cathodes – A Prospective Solution to the Battery Industry's Cobalt Problem*

Lithium-ion batteries are over-reliant on cobalt-containing cathodes. Current projections estimate hundreds of millions of electric vehicles (EVs) will be on the road by 2050, and this ever-growing demand threatens to deplete global cobalt reserves at an alarming rate. Moreover, cobalt supply-chain issues have significantly increased cobalt prices throughout the last decade. As such, energy storage research and development need to reduce reliance on cobalt to meet ever-growing demands for lithium-ion batteries. This chapter summarizes the science/technology gaps and potential of numerous cobalt-free Li-ion cathodes, including layered, spinel, olivine, and disordered rocksalt systems. Despite the promising performance of these Co-free cathodes, scale-up and manufacturing bottlenecks associated with these materials must also be addressed to enable widespread adoption in commercial batteries. Overall, this review broadly highlights the enormous promise of “zero-cobalt” Li-ion batteries to enable sustainable production of EVs in the coming decades.

Muralidharan, Nitin↗
DOE OSTI2023

Demarcating the Impact of Electrolytes on High–Nickel Cathodes and Lithium–Metal Anode

The ever-growing demand for low-cost, high-energy-density lithium-ion batteries (LIBs) makes high-nickel layered oxide cathodes, especially LiNiO 2 (LNO), one of the most appealing candidates. However, poor structural and surface instability that leads to a short cycle life remains a formidable challenge. Herein, a systematic investigation of LNO performance in two different electrolytes (a conventional carbonate-based LP57 electrolyte and an ether-based localized high-concentration electrolyte (LHCE)) with different charge cut-off voltages is presented. These findings show that the cathode-electrolyte reactivity is the main factor dictating the performance degradation of LNO at high voltages rather than bulk integrity. While LHCE can provide good stability beyond 4.2 V with a robust, uniform solid–electrolyte interphase (SEI) layer on the Li-metal anode, there is no significant difference in cyclability at 4.15 V (96% capacity retention after 200 cycles) for both LP57 and LHCE. From LNO symmetric cells, carbonate-based electrolyte is found to be good for LNO stability while ether-based electrolyte is beneficial toward Li-metal anode. Furthermore, a suitable electrolyte or a low cut-off voltage is necessary to maintain a decent cycle life. Altogether, this work highlights the impact of electrolyte and cut-off voltage on LNO and Li-metal, which can help guide the development of cells based on LNO.

25 ENERGY STORAGE↗
DOE OSTI2022

Next-Generation Cobalt-Free Cathodes – A Prospective Solution to the Battery Industry's Cobalt Problem

Lithium-ion batteries are overreliant on cobalt containing cathodes. Current projections estimate that hundreds of millions of electric vehicles (EVs) will be on the road by 2050, and this ever-growing demand threatens to deplete global cobalt reserves at an alarming rate. Moreover, cobalt supply chain issues have significantly increased cobalt prices throughout the last decade. As such, energy storage research and development need to reduce the reliance on cobalt to meet ever-growing demand for lithium-ion batteries. The present review summarizes the science and technology gaps and potential of numerous cobalt-free Li-ion cathodes including layered, spinel, olivine, and disordered rock-salt systems. Despite the promising performance of these Co-free cathodes, scale-up and manufacturing bottlenecks associated with these materials must also be addressed to enable widespread adoption in commercial batteries. Overall, this review broadly highlights the enormous promise of “zero-cobalt” Li-ion batteries to enable sustainable production of EVs in the coming decades.

25 ENERGY STORAGE↗
DOE OSTI2023

Stable Cycling with Intimate Contacts Enabled by Crystallinity–Controlled PTFE–Based Solvent–Free Cathodes in All–Solid–State Batteries

All-solid-state batteries (ASSBs) employing Li-metal anodes and inorganic solid electrolytes are attracting great attention due to high safety and energy density for next-generation energy storage devices. However, the volume change of cathode active materials can cause contact loss, resulting in charge carrier isolation, heterogeneous current distribution, and poor electrochemical properties in ASSBs. Here, a simple, yet effective, solvent-free electrode engineering approach with polytetrafluoroethylene (PTFE) as a binder for ASSBs is reported, enabling intimate contact and stable interfaces with the cathode. It is substantiated that the crystallinity of PTFE can be controlled depending on the heat history, and highly crystalline PTFE displays robust mechanical properties. High-nickel LiNi 0.8 Mn 0.1 Co 0.1 O 2 cathode prepared with crystalline PTFE show improved cycle and rate performances in ASSBs. In addition, it is revealed that the intimate contact between cathode particles with a stable cathode electrolyte layer is maintained during cycling by postmortem studies. Furthermore, this simple engineering method can be applied to prepare cathodes with a variety of active materials and solid electrolytes in ASSBs.

25 ENERGY STORAGE↗
DOE OSTI2020

A Review of the Use of Immobilized Ionic Liquids in the Electrochemical Conversion of CO2

This paper is a review on the application of imidazolium-based ionic liquids tethered to polymer backbones in the electrochemical conversion of CO2 to carbon monoxide and formic acid. These tethered ionic liquids have been incorporated into novel anion ion exchange membranes for CO2 electrolysis, as well as for ionomers that have been incorporated into the cathode catalyst layer, providing a co-catalyst for the reduction reaction. In using these tethered ionic liquids in the cathode catalyst composition, the cell operating current increased by a factor of two or more. The Faradaic efficiencies also increased by 20–30%. This paper provides a review of the literature, in addition to providing some new experimental results from Dioxide Materials, in the electrochemical conversion of CO2 to CO and formic acid.

09 BIOMASS FUELS↗
DOE OSTI2021

Method of protecting sulfur cathode materials for alkali metal-sulfur secondary battery

Provided is a method of producing a rechargeable alkali metal-sulfur cell, comprising: (a) providing an anode layer; (b) providing particulates comprising primary particles of a sulfur-containing material encapsulated or embraced by a thin layer of a conductive sulfonated elastomer composite, wherein the conductive sulfonated elastomer composite comprises from 0% to 50% by weight of a conductive reinforcement material dispersed in a sulfonated elastomeric matrix material, and the conductive sulfonated elastomer composite has a thickness from 1 nm to 10 μm, a fully recoverable tensile strain from 2% to 500%, a lithium ion conductivity from 10−7 S/cm to 5×10−2 S/cm, and an electrical conductivity from 10−7 S/cm to 100 S/cm; (c) forming the particulates, a resin binder, and an optional conductive additive into a cathode layer; and (d) combining the anode layer, the cathode layer, an optional porous separator, and an electrolyte to form the alkali metal-sulfur cell.

Zhamu, Aruna↗
DOE OSTI2026

Impact of Anode to Cathode Crossover in Lithium‐metal Batteries With High‐Nickel Cathodes

The advancement of high-energy-density lithium-metal batteries (LMBs) is hindered by the chemical instability of both lithium-metal anode and high-nickel layered oxide cathodes. While cathode-to-anode crossover is well-documented, the reverse process of anode-to-cathode crossover remains underexplored. Here, we systematically investigate such crossovers and the degradation pathway in pouch cells with a localized high-concentration electrolyte, comparing NMC622, NMC811, and NMC90 cathodes paired with lithium-metal and graphite anodes. Despite delivering higher initial capacities, LMBs exhibit faster capacity fade under long-term cycling at 45 °C. To isolate cathode-side degradation, galvanostatic electrochemical impedance spectroscopy (GEIS) measurements of cycled cathodes paired with delithiated lithium iron phosphate (LFP) counter electrodes reveal significantly higher charge-transfer resistance in cathodes cycled with lithium-metal. Surface characterization via X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS) reveals greater electrolyte decomposition on cathodes cycled with lithium metal, leading to thicker, more organic-rich cathode–electrolyte interphases (CEIs), consistent with the elevated charge-transfer resistance observed in GEIS measurements. Notably, NMC90 shows the most pronounced CEI thickening, linking higher cathode surface reactivity to greater susceptibility to anode-to-cathode crossover. This work presents compelling evidence of crosstalk degradation originating from lithium-metal anodes and underscores the importance of cross-interface stability for the design of durable LMBs.

25 ENERGY STORAGE↗
DOE OSTI2024

Structural and chemical evolutions of a magnesium vanadium oxide cathode under electrochemical cycling in magnesium batteries

The design of cathode materials that remain chemically and structurally stable during repetitive ion insertion and extraction poses a significant challenge in developing multivalent batteries. The cycling stability of traditional metal oxide-based cathode is challenged by sluggish diffusion of multivalent cations and parasitic reactivity at interfacial regimes, including the cathode electrolyte interphase layer (CEI). Understanding the reactions at the cathode-electrolyte interface, particularly those induced by non-stoichiometric surface layers, is a crucial design parameter for both cathode materials and electrolytes. Here, in this study, we employed multimodal analysis, including in situ and ex situ X-ray photoelectron spectroscopy (XPS), high resolution transmission electron microscopy (TEM) and electrochemical impedance spectroscopy (EIS) to examine the surface reactions and subsequent structural and chemical evolutions of the CEI on high voltage magnesium vanadium oxide (MgV 2 O 4 ) spinel cathode during the Mg 2+ insertion/extraction processes. The results revealed that the presence of non-stoichiometric surface layers in the magnesium vanadium oxide cathode drive the decomposition of bis(trifluoromethanesulfonyl)imide (TFSI - ) anion, leading to the formation of the CEI layer. The CEI layer could inhibit the Mg 2+ ion transfer processes. Accompanying this reactivity-driven degradation, the magnesium vanadium oxide cathode undergoes pulverization, forming clusters of nanosized particles. This process likely improves cycling ability by creating new intercalation sites and shortening the diffusion pathway for the Mg 2+ cations. This study demonstrates that controlling surface stoichiometry and engineering morphological properties are critical design parameters for high performance cathodes for multivalent batteries.

25 ENERGY STORAGE↗
DOE OSTI2026

Ionic Interdiffusion at Cathode|Solid-Electrolyte Interface: A Machine Learning–Assisted Multiscale Investigation and Mitigation Strategies

Future lithium batteries are expected to use solid electrolytes to achieve higher energy density and fast charge capabilities. However, most solid electrolytes are thermodynamically unstable against layered oxide cathodes. In this study, the stability of LiCoO2 (LCO) cathode with Li10GeP2S12 (LGPS) solid electrolyte is investigated using ab initio molecular dynamics (AIMD) and machine learning molecular dynamics (MLMD). The propensity of ionic interdiffusion, formation of a passivating interphase layer, and corresponding decay in cell performance is addressed using a continuum model. Large-scale MLMD simulations confirm that the LCO|LGPS interface permits interdiffusion of cobalt (Co) and other ionic species, leading to the formation and growth of a resistive interphase and to dramatic capacity fade even in the first cycle. We examine the literature evidence that incorporating a thin layer of LiNb0.5Ta0.5O3 (LNTO) between LCO and LGPS prevents the interdiffusion of ions. Atomistic simulations suggest that substituting lithium (Li) in LNTO with Co is thermodynamically unfavorable, thereby inhibiting ionic interdiffusion. The stable Nb5+/Ta5+ states form a rigid metal-oxide framework, which consequently also prevents the substitution of niobium (Nb) or tantalum (Ta). However, continuum-level analysis suggests that the higher mechanical stiffness of LNTO can lead to interfacial delamination between the LCO and LNTO. This phenomenon reduces the effectiveness of the protective layer. This paper, therefore, highlights the need to develop novel interlayers that balance low ionic interdiffusion with low mechanical stiffness.

Ncube, Musawenkosi K.↗
DOE OSTI2023

A High Energy–Density, Cobalt–Free, Low–Nickel LiNi 0.7 Mn 0.25 Al 0.05 O 2 Cathode with a High–Voltage Electrolyte for Lithium–Metal Batteries

Cobalt-free cathode materials have garnered increased attention for applications in next-generation batteries for electric vehicles, as cobalt is considered to have at a high supply chain risk. Here, the use of a localized saturated electrolyte (LSE) to enable stable cycling of a cobalt-free, low-nickel layered-oxide cathode LiNi 0.7 Mn 0.25 Al 0.05 O 2 (NMA-70) to higher voltages (4.6 V) in a lithium-metal battery is demonstrated. Compared to the baseline LP57 electrolyte, the LSE extends the cycle life from ≈100 cycles to ≈400 cycles before reaching 80% capacity retention. Visual indicators of cell degradation, such as product deposition, are observed on electrodes cycled in LP57. It is shown that cycling NMA-70 in LSE reduces the overall active material loss and overpotential growth during extended cycling. This is attributed to the formation of a beneficial fluorinated interphase layer, a lower degree of rock-salt phase formation, and a reduction in the gas evolution from the cathode surface. The decrease in gas evolution from the cathode cycled in LSE reflects a lower degree of electrolyte reactivity and an overall improvement in the safety characteristics of the cell. Furthermore, this study highlights the importance of a stable electrolyte to enable the high-voltage cycling of alternative, lower nickel, and cobalt-free cathodes.

25 ENERGY STORAGE↗
DOE OSTI2025

Promising performance of sulfide catholytes compared to halide alternatives in NMC811 cathodes for sheet-type sulfide solid-state batteries

Sulfide-based solid-state batteries (SSBs) show promise in achieving energy densities over 350 Wh/kg, yet challenges persist with their incorporation of high-voltage, nickel-rich layered oxide cathodes, such as LiNi₀.₈Mn₀.₁Co₀.₁O₂ (NMC811), due to the poor oxidation stability of sulfide solid-state electrolytes (SSEs) like Li₆PS₅Cl (LPSCl). Although halide SSEs such as Li₃InCl₆ (LIC) and Li₃YCl₆ (LYC) have previously shown promise in stabilizing high-voltage NMC cathodes, our research reveals that sulfide SSE catholytes, particularly when combined with surface-coated NMC cathodes, deliver superior performance. Here, this investigation assesses the cycling stability of various catholytes—LPSCl, LIC, Li₁₀GeP₂S₁₂ (LGPS), combined LIC-LPSCl, and LYC-LPSCl—in SSBs with LiNbO₃-coated NMC811 cathodes against sheet-type LPSCl separators. Findings indicate that while LGPS-based cathodes maintain higher capacity retention, they yield lower deliverable capacity, and LIC cathodes experience significant electrochemical degradation. Importantly, our results underscore that sulfide SSE catholytes, in conjunction with LiNbO₃-coated cathodes, optimize the cathode-electrolyte interphase (CEI), enhancing both kinetics and mass transport. These insights provide a strategic direction for optimizing catholyte composition in the development of sheet-type sulfide-based SSBs.

Catholyte↗
DOE OSTI2021

Effect of Catalyst and Catalyst Layer Composition on Catalyst Support Durability

Polymer electrolyte membrane fuel cells (PEMFCs) are efficient, zero-emission engines for the automotive sector. However, cost and durability are major barriers for the commercialization of PEMFCs. Degradation of the carbon support in the cathode catalyst layer due to high potential excursions caused by unmitigated events like H 2 starvation, or start-up/shutdown are still a major durability issue in PEMFCs. Catalyst support durability was studied by accelerated stress tests (ASTs) that included repeated potential cycling from 1.0 to 1.5 V. The effect of catalyst layer composition on carbon corrosion was studied using membrane electrode assemblies with different catalysts (Pt, PtCo), catalyst composition (catalyst wt.%, supports), ionomer composition (loading, and equivalent weights). The corrosion of the carbon support is similar between Pt and PtCo catalysts. However, the performance degradation rate is higher for the alloy catalysts due to differences in catalyst particle size and the transition metal’s leaching accelerating the performance degradation. The carbon loss is lower for catalysts with lower initial carbon loading (or higher catalyst wt.%), which is better for durability. However, the cumulative loss of carbon is identical for electrodes with the same catalyst support irrespective of catalyst and ionomer composition in the catalyst layer.

25 ENERGY STORAGE↗
DOE OSTI2025

Maximizing Calendering Effects Through the Mechanical Pulverization of Co-Free Nickel-Rich Cathodes in Lithium-Ion Cells

Calendering is a technique used to maximize the volumetric energy density of battery electrodes. However, higher amounts of calendering result in increased tortuosity and particle cracking. We propose a novel packing structure of electrode particles to maximize calendering benefits while minimizing particle fracture. Cobalt-free layered oxide cathode LiNi0.92Mn0.04Al0.04O2 (NMA) particles are pulverized through ball-milling and coated with lithium phosphate. Pulverized and pristine NMA are fabricated into “bimodal” electrodes, whereas “unimodal” electrodes consist of only pristine NMA. Each electrode type was made into 30% porosity, 40% porosity, and uncalendered coin cell samples. X-ray diffraction suggests that the unimodal samples suffer from more particle fracture than the bimodal samples when calendered to the same porosity of 30%. Electrochemical impedance spectroscopy suggests that the bimodal electrodes exhibit lower surface film resistance. This is supported by enhanced capacity retention for the bimodal samples after 100 cycles.

25 ENERGY STORAGE↗
DOE OSTI2024

Deconstructing the High Voltage Degradation Mechanisms in Na 2/3 Ni 1/3 Mn 2/3 O 2 with Single Crystals and Advanced Electrolyte

Abstract Sodium layered oxide cathodes can uniquely benefit from the existing lithium‐ion battery industry as sodium‐ion batteries gain traction as a potential low‐cost, drop‐in replacement. However, achieving relevant energy density with a suitable cycle life remains a challenge for sodium layered oxides. At high operating potentials, several competing degradation mechanisms prevent P2‐type Na 2/3 Ni 1/3 Mn 2/3 O 2 (≈550 Wh kg −1 ) from achieving meaningful cycle life—with bulk structural instability and surface reactivity being the primary retractors. Herein, the issue of particle cracking is addressed through detailed synthesis methods of “single‐crystal” materials. By comparison to a polycrystalline baseline, the single‐crystal materials quantify the capacity loss due to isolation of active material caused by intergranular particle cracking. The single crystal materials are then employed in cells with an advanced, “localized saturated electrolyte” (LSE) to demonstrate the magnitude of capacity loss due to electrolyte decomposition at the cathode surface. Mitigation of the surface reactivity through the LSE electrolyte effectively demonstrates the elevated importance of surface reactivity at high voltages despite the onset of egregious particle cracking. This work aims to guide future research into understanding molten‐salt assisted syntheses and advance the debate on surface versus bulk degradation.

Darga, Joe↗
DOE OSTI2024

Insight of Synthesis of Single Crystal Ni-Rich LiNi 1-x-y Co x Mn y O 2 Cathodes

Single-crystal Ni-rich LiNi 1-x-y Co x Mn y O 2 (NCM) cathodes have garnered widespread attention in the lithium-ion battery community due to their unique advantages in mechanical performance and their ability to minimize interfacial electrochemical side reactions. The synthesis of single-crystal materials with monodisperse and appropriate size, minimal lattice defects, and highly ordered structures is the key for high-performance batteries. However, achieving this goal poses challenges due to the lack of in-depth understanding regarding specific experimental parameters and the solid reaction mechanism during the synthesis process. Further, in this review, the aim is to provide an in-depth analysis of the critical process parameters involved in the synthesis and their impact on crystal morphology, structure, and electrochemical performance. Consequently, the first section focuses on the effect of the precursor morphology, lithium salt, atmosphere, and sintering procedure. In the second section, the study delves into an in-depth discussion of the solid reaction and crystal growth mechanism. Lastly, it is concluded by highlighting the prospects and challenges associated with the synthesis and application of single-crystal Ni-rich NCM cathodes.

25 ENERGY STORAGE↗