Search NASA⌕ Search

SEARCH · Search NASA

Results for “lithium metal anode stabilization”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 271 records · Page 15
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Data-driven search for promising intercalating ions and layered materials for metal-ion batteries

The rise in demand for lithium-ion batteries has led to a large-scale search for electrode materials and intercalating ion species to meet the demands of next-generation energy technologies. Recent efforts largely focus on searching for cathodes that can accommodate large amounts of intercalating ions, but similar work on anodes is relatively limited. This study utilizes machine learning methods to find alternative two-dimensional (2D) materials and intercalating ions beyond Li for metal-ion batteries with high-power efficiencies. The approach first uses density functional theory (DFT) calculations to estimate the theoretical capacities and voltages of various metal ions on 2D materials. The DFT-generated data also provide insights into the local structural accommodation upon ion intercalation on various 2D materials. Significant changes to the lattice can result in irreversible changes to the bonding environments in the anode material, resulting in poor cycling stability. Next, this study develops a binding energy and structural accommodation-based classification model to screen anode materials for next-generation batteries. The classification model selects intercalating ions and 2D material pairs suitable for batteries based on the calculated voltage and volumetric changes in the 2D material upon intercalation. Finally, this study builds a regression model to accurately predict the binding energies of the various intercalating ions on 2D materials. The approach highlights the importance of different elemental and structural features for classification and regression tasks. In conclusion, the insights gained from this study on the role of involved features, such as electronegativities of the constituent ions and the presence of unfilled electronic levels, will help to streamline further studies towards the search for future layered battery materials.

36 MATERIALS SCIENCE↗
DOE OSTI2022

High Energy Aqueous Lithium-Ion Batteries (Final Report)

Lithium-ion batteries (LIBs) are a widely used energy storage device. For decades, researchers have been studying aqueous electrolytes due to their non-flammability and environmental friendless. However, the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) of water greatly limit the voltage window of the aqueous electrolyte. The recent concept of ‘solvent-in-salt’ electrolytes, namely ‘water-in-salt’ electrolytes (WISE) for aqueous batteries and ‘super-concentrated’ electrolytes for non-aqueous batteries, greatly expands the electrochemical window of these battery systems and consequently their energy density. This expansion occurs because the large number of salt aggregates in ‘solvent-in-salt’ electrolytes enables preferential salt decomposition over solvent decomposition to form robust interphase layers on electrodes, thus enhancing their stability in a wide range of operating voltages. However, even when the salt concentration reached 63m, regardless of cost, the cathodic potential of the WISE expanded only to 1.75V with an overall electrochemical stability window of <3.25V. To design the next generation of high energy aqueous LIBs, electrolytes that possess a wider electrochemical stability window and lower cost but still maintain the merit of non-flammability are much needed. In this project, we designed the aqueous LIBs with widened voltage window. We reported a cheap and non-flammable ternary eutectic electrolyte that can form a robust solid electrolyte interface (SEI)so that the cathodic limiting potential can be decreased to <1.5 V for Li 4 Ti 5 O 12 anodes, while maintaining both a high ionic conductivity of >10 -3 S cm –1 and a low viscosity. We demonstrated the super-stable2.5V LiMn 2 O 4 ||Li 4 Ti 5 O 12 pouch cell with mass loading of 2.5 mAh/cm. Further, LiCl-LiBr-Graphite/Li full cells were designed with high energy density. Finally, we use a bi-layer design to enlarge the voltage window of aqueous electrolyte, which can endow the stable cycling of aqueous Lithium metal batteries.

25 ENERGY STORAGE↗
DOE OSTI2024

Magnetically oriented nanosheet interlayer for dynamic regeneration in lithium metal batteries

Lithium (Li) metal has been recognized as a promising anode to advance the energy density of current Li-based batteries. However, the growth of the solid–electrolyte interphase (SEI) layer and dendritic Li microstructure pose significant challenges for the long-term operation of Li metal batteries (LMBs). Herein, we propose the utilization of a suspension electrolyte with dispersed magnetically responsive nanosheets whose orientation can be manipulated by an external magnetic field during cell operation for realizing in situ regeneration in LMBs. The regeneration mechanism arises from the redistribution of the ion flux and the formation of an inorganic-rich SEI for uniform and compact Li deposition. With the magnetic-field-induced regeneration process, we show that a Li||Li symmetric cell stably operates for 350 h at 2 mA cm −2 and 2 mA h cm −2 , ~5 times that of the cell with the pristine electrolyte. Furthermore, the cycling stability can be significantly extended in the Li||NMC full cell of 3 mA h cm −2 , showing a capacity retention of 67% after 500 cycles at 1C. The dynamic Li metal regeneration demonstrated here could bring useful design considerations for reviving the operating cells for achieving high-energy, long-duration battery systems.

Ju, Zhengyu↗
DOE OSTI2021

DEVELOPMENT OF STABLE ANODE AND CATHODE MATERIALS FOR RECHARGEABLE BATTERIES

Batteries have been employed in a variety of applications, such as portable electronics, electric vehicles (EVs), and stationary energy storage to preserve energy from other renewable sources (like wind or solar energy). The ultimate goal is to develop high energy density, long life span, better safety, and low cost of the batteries. However, current commercialized batteries (like lead-acid, zinc-alkaline, lithium-ion batteries (LIBs)) could not fulfill all the demands of diversified applications. LIBs predominate the market because of their high energy density. To achieve a higher capacity of the cell, high-nickel layered (Ni > 90%) cathode materials are promising candidates since they compose high specific capacity and discharge voltage. In chapter 1, an introduction to cell energy density and the development of high-nickel layered cathode materials along with associated obstacles of poor cycling stability and thermal stability have been discussed. Associated works like doping or surface coating have also been mentioned in this section. In chapter 2, Al doping in high-nickel layered cathode materials to enhance the structural and thermal stability was introduced. Uniform incorporation of Al doping is achieved by mechanical fusion and calcination processes. The Al doping not only decreased the Li/Ni mixing ratio but also enhance the thermal resistance to oxygen evolution because of strong Al-O bonding, which leads to elevated electrochemical and thermal stability. In chapter 3, TiN is implemented as a Ti dopant for high-nickel layered cathode materials to improve the electrochemical performance in the LIBs. The Ti not only diffused within the bulk structure but also formed segregation on the surface, which improved the structural stability and led to better cycling performance. Although LIBs deliver high energy density, safety concerns of flammable organic electrolytes have not been resolved yet. Therefore, the aqueous rechargeable zinc-ion batteries (ZIB) have been praised for their safe, low-cost, eco-friendly stationary energy storage, which is considered as a complementary system to LIBs. In chapter 4, the mechanism, advantages, and challenges of ZIBs would be given and the strategies for solving the zinc metal anode issues have been discussed in this section. In chapter 5, a polymer coating method was reported to facilitate Zn deposition/ stripping by coordination with Zn2+ and prevented direct contact with aqueous electrolyte to block corrosion side-reactions. With this coating, a boost in a lifetime (up to 400 hours) and lower polarization under extremely high current conditions (10 mA cm-2) have been achieved in repeated Zn deposition/ stripping cycling.

25 ENERGY STORAGE↗
DOE OSTI2020

Safe, Low-Cost, High Energy-Density, Solid-State Li-Ion Batteries

We developed intrinsically safe, robust, low-cost, high-energy-density solid-state Li-ion batteries, by integrating high conductivity garnet-type solid Li ion electrolytes and several different cathodes in tailored microstructures, fabricated by low-cost supported thin-film ceramic techniques, to overcome the primary technological barriers to next generation battery technology. In this ARPA-E project we employed Li-garnet solid-state electrolytes pioneered by one of the co-investigators (Thangadurai) which has room temperature (RT) conductivity of ~10 -3 S cm -1 . The highly stable garnet SSE allowed the use of S, NMC, and other cathodes with Li metal anodes without stability or flammability concerns. We studied the garnet’s stability when exposed to CO 2 and humidity (with or without an ALD coating) and showed that the material can be processed in ambient air for most steps prior to battery assembly, significantly reducing production costs. We extensively studied and scaled up the synthesis of the powder and explored external suppliers of garnet to determine the best pathway for commercial success. We used low-cost and scalable tapecasting fabrication methods to create porous-dense-porous “trilayer” solid electrolyte microstructures with a ~20 μm separating dense layer, and >70% porosity porous layers to host the electrodes. These scalable multilayer ceramic fabrication techniques, without need for dry rooms or vacuum equipment, also provide for dramatically reduced manufacturing costs. The tailored microstructured electrode supports (scaffold) increased interfacial area ~50x, overcoming the high impedance typical of planar geometry SSLiBs, resulting in record-setting 10 mA/cm 2 lithium cycling in a symmetric cell. We expanded our tapecasting ability and showed tapes >25m in length by the end of the project. We demonstrated the ability to sinter garnet without the use of a garnet powderbed, which could have been a major obstacle and waste of material at scale. At the same time, we expanded the size of our trilayers from coin cells (0.7 cm 2 ) to the full format design (30 cm 2 ). To develop full cells, we demonstrated 250 Wh/kg at room temperature with commercial NMC electrode films in a bilayer configuration. Similarly, we demonstrated 280 Wh/kg trilayer Li-S cells at room temperature with >90% capacity retention over 300 cycles. At 90°C we demonstrated 350 Wh/kg with a Li-S trilayer. The high thermal stability of the garnet electrolyte also enabled extended cycling (400 cycles) of a Li-TiS 2 cell at 150 °C, showcasing the exceptional safety and nonflammability of the solid-state trilayer batteries. Ion Storage Systems has taken this technology and knowledge to produce trilayer garnet electrolytes and is building out facilities to commercialize high performance solid state batteries. ISS has hired a strong staff, identified and communicated with a large number of potential partners, and successfully secured follow-on funding.

25 ENERGY STORAGE↗
DOE OSTI2020

Synthesis of LiNiO 2 at Moderate Oxygen Pressure and Long-Term Cyclability in Lithium-Ion Full Cells

The widespread adoption of electric vehicles necessitates higher-energy-density and longer-life cathode materials for Li-ion batteries. LiNiO 2 offers a higher energy density at a lower cost than other high-Ni-content cathodes containing additional transition-metal ions. However, detrimental phase transformations and impedance growth, resulting from structural defects formed during synthesis, lead to poor cyclability and limit the practical viability of LiNiO 2 . Herein, we demonstrate a considerably improved cycle life for LiNiO 2 by synthesizing it under a pressurized oxygen environment. The capacity retention in pouch-type full cells with a graphite anode after 1000 cycles is increased from 59 to 76% by applying a mere 1.7 atm of oxygen pressure during the synthesis of LiNiO 2 . With iodometric titration and inductively coupled plasma optical emission spectroscopy analysis, we provide clear evidence that oxygen pressure during synthesis reduces the occurrence of lattice oxygen vacancies and increases the content of Ni 3+ in LiNiO 2 , improving its structural integrity and cyclability. Post-mortem analysis of the cycled cathodes provides insights into the sources of degradation occurring during long-term cycling. Here, this work demonstrates a practically viable, synthetic approach combined with doping and coating to achieve improved performance with high-Ni layered oxide materials. Furthermore, this work represents the first report of extended cycling of LiNiO 2 in pouch full cells with graphite anode and will, therefore, serves as an important benchmark for future research on LiNiO 2 .

25 ENERGY STORAGE↗
DOE OSTI2020

Recent Progress in High Donor Electrolytes for Lithium–Sulfur Batteries

Lithium–sulfur (Li–S) batteries continue to be considered promising post-lithium-ion batteries owing to their high theoretical energy density. In pursuit of a Li–S cell with long-term cyclability, most studies thus far have relied on using ether-based electrolytes. However, their limited ability to dissolve polysulfides requires a high electrolyte-to-sulfur ratio, which impairs the achievable specific energy. Recently, the battery community found high donor electrolytes to be a potential solution to this shortcoming because their high solubility toward polysulfides enables a cell to operate under lean electrolyte conditions. Despite the increasing number of promising outcomes with high donor electrolytes, a critical hurdle related to stability of the lithium-metal counter electrode needs to be overcome. This review provides an overview of recent efforts pertaining to high donor electrolytes in Li–S batteries and is intended to raise interest from within the community. Furthermore, based on analogous efforts in the lithium-air battery field, strategies for protecting the lithium metal electrode are proposed. In this review, it is predicted that high donor electrolytes will be elevated to a higher status in the field of Li–S batteries, with the hope that either existing or upcoming strategies will, to a fair extent, mitigate the degradation of the lithium–metal interface.

25 ENERGY STORAGE↗
DOE OSTI2024

Electro-Chemo-Mechanical Evolution at the Garnet Solid Electrolyte–Cathode Interface

Solid-state batteries promise higher energy density and improved safety compared with lithium-ion batteries. However, electro-chemomechanical instabilities at the solid electrolyte interface with the cathode and the anode hinder their large scale implementation. Here, in this study, we focus on resolving electro-chemo-mechanical instability mechanisms and their onset conditions between a state-of-the-art cathode, LiNi 0.6 Mn 0.2 Co 0.2 O 2 (NMC622), and the garnet Li 7 La 3 Zr 2 O 12 (LLZO) solid electrolyte. We used thin-film NMC622 on LLZO pellets to place the interfacial region within the detection depth of the X-ray characterization techniques. The experimental probes of the near-interface region included in operando X-ray absorption spectroscopy and ex situ focused ion beam scanning electron microscopy. Electrochemical degradation was not observable during cycling at room temperature with 4.3 V versus Li/Li + charge voltage cutoff, or with stepwise potentiostatic hold up to 4.1 V versus Li/Li + . In contrast, secondary phases including reduced transition metal species (Ni 2+ , Co 2+ ) were found after cycling up to 4.3 V versus Li/Li + at 80 °C and during potentiostatic hold at 4.3 V versus Li/Li + (Ni 2+ ). Intergranular cracks between NMC622 grains and delamination at the NMC622|LLZO interface occurred readily after the first charge. These interface reaction products and mechanical failure lowered the capacity and cell efficiency due to partial loss of the NMC622 phase, partial loss of contact at the interface, and a higher polarization resistance. Electrochemical instability between delithiated NMC622 and LLZO could be mitigated by using a low charge voltage cutoff or cycling at lower temperature. Ways to engineer the mechanical properties to avoid crack deflection and delamination at the interface are also discussed for enhancing mechanical stability.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Stability and Performance of 3d Transition Metal Carbo‐Sulfides: A Density Functional Theory Exploration for Li‐Ion Battery Anodes

As the demand for high-performance and reliable energy storage devices continues to rise, identifying new anode materials is crucial for advancing Li-ion battery (LIB) technology. Inspired by recent experimental breakthroughs in synthesizing two-dimensional transition metal carbo-chalcogenides (2D-TMCCs), density functional theory calculations are performed to systematically explore their sulfide variants (TM 2 S 2 C) spanning all 3d transition metals in three possible phases. Through comprehensive evaluations of thermodynamic, dynamic, mechanical, and thermal stabilities, seven stable 2D-TMCC candidates are identified, four of which exhibit superior battery performance. Notably, V-based 2D-TMCCs across all three phases deliver moderate open-circuit voltages (OCV), efficient Li diffusion, and substantial capacities, making them promising candidates for industrial applications without requiring specific phase controls. A Cr-based 2D-TMCC (with sulfur atoms above carbon atoms) offers the highest capacity of 515.40 mAh g −1 , the lowest Li diffusion barrier, and an optimal OCV, highlighting its appealing potential as an anode material for LIBs. Furthermore, significant Li–Li spacing and pronounced electron delocalization in these four 2D-TMCCs suggest a reduced risk of dendrite formation. This work expands the 2D-TMCC family and identifies up-and-coming candidates for next-generation LIB anodes.

anode materials↗
DOE OSTI2020

Exploiting the Spinel Structure for Li-ion Battery Applications: A Tribute to John B. Goodenough

This review provides a personal account of career-long efforts, interwoven with the contributions of others, to exploit the [B 2 ]O 4 framework of an A[B 2 ]O 4 spinel structure for lithium-ion battery applications, where A = Li, and B is one or more metal cations. The narrative begins at the Council for Scientific and Industrial Research (CSIR) in South Africa in the mid-1970s when, in response to the Middle East oil crisis, worldwide efforts were turned to develop high-temperature sodium and lithium batteries to power electric vehicles. In 1981, results in CSIR's program on a high-temperature lithium battery led to a collaborative project on room-temperature lithium cells with Prof. John B. Goodenough at Oxford University, where studies of Fe 3 O 4 , Mn 3 O 4 , and LiMn 2 O 4 cathodes led to the recognition of the broad utility of the [B2]O4 spinel framework as an anode, cathode, or solid electrolyte for rechargeable lithium cells. This finding has had a profound and lasting impact, influencing further ideas and discoveries at the CSIR, Argonne National Laboratory, and elsewhere. The narrative emphasizes the compositional versatility of the spinel structure and the opportunities to tailor the electrochemical potential and stability of a Li-ion cell.

25 ENERGY STORAGE↗
DOE OSTI2019

Dendrite–Free Potassium Metal Anodes in a Carbonate Electrolyte

Potassium (K) metal anodes suffer from a challenging problem of dendrite growth. In this study, it is demonstrated that a tailored current collector will stabilize the metal plating–stripping behavior even with a conventional KPF 6 –carbonate electrolyte. A 3D copper current collector is functionalized with partially reduced graphene oxide to create a potassiophilic surface, the electrode being denoted as rGO@3D–Cu. Potassiophilic versus potassiophobic experiments demonstrate that molten K fully wets rGO@3D–Cu after 6 s, but does not wet unfunctionalized 3D–Cu. Electrochemically, a unique synergy is achieved that is driven by interfacial tension and geometry: the adherent rGO underlayer promotes 2D layer–by–layer (Frank–van der Merwe) metal film growth at early stages of plating, while the tortuous 3D–Cu electrode reduces the current density and geometrically frustrates dendrites. The rGO@3D–Cu symmetric cells and half–cells achieve state–of–the–art plating and stripping performance. Here, the symmetric rGO@3D–Cu cells exhibit stable cycling at 0.1–2 mA cm –2 , while baseline Cu prematurely fails when the current reaches 0.5 mA cm –2 . The half–cells cells of rGO@3D–Cu (no K reservoir) are stable at 0.5 mA cm –2 for 10 000 min (100 cycles), and at 1 mA cm –2 for 5000 min. The baseline 3D–Cu, planar rGO@Cu, and planar Cu foil fails after 5110, 3012, and 1410 min, respectively.

25 ENERGY STORAGE↗
DOE OSTI2024

Recent Progress on Dominant Sulfide‐Type Solid‐State Na Superionic Conductors for Solid‐State Sodium Batteries

Abstract Over the past decade, solid‐state batteries have garnered significant attentions due to their potentials to deliver high energy density and excellent safety. Considering the abundant sodium (Na) resources in contrast to lithium (Li), the development of sodium‐based batteries has become increasingly appealing. Sulfide‐based superionic conductors are widely considered as promising solid eletcrolytes (SEs) in solid‐state Na batteries due to the features of high ionic conductivity and cold‐press densification. In recent years, tremendous efforts have been made to investigate sulfide‐based Na‐ion conductors on their synthesis, compositions, conductivity, and the feasibility in batteries. However, there are still several challenges to overcome for their practical applications in high performance solid‐state Na batteries. This article provides a comprehensive update on the synthesis, structure, and properties of three dominant sulfide‐based Na‐ion conductors (Na 3 PS 4 , Na 3 SbS 4 , and Na 11 Sn 2 PS 12 ), and their families that have a variety of anion and cation doping. Additionally, the interface stability of these sulfide electrolytes toward the anode is reviewed, as well as the electrochemical performance of solid‐state Na batteries based on different types of cathode materials (metal sulfides, oxides, and organics). Finally, the perspective and outlook for the development and practical utilization of sulfide‐based SE in solid‐state batteries are discussed.

Guo, Xiaolin↗
DOE OSTI2022

Understanding Solid-Electrolyte Interphase Formation at the Lithium Metal Anode of Lithium-Sulfur Batteries

Lithium-sulfur (Li-S) batteries are one of the most promising chemistries for the next generation of energy storage devices. In a standard Li-S cell, the metallic lithium anode is an essential component of the battery due to its low density, extremely high theoretical specific capacity, and very low negative electrochemical potential. However, several challenges related to the use of Li metal have prevented this battery technology from becoming commercially available. For instance, Li-anodes are highly reactive, which results in the continuous decomposition of the electrolyte and the formation of the solid-electrolyte interphase (SEI) layer. This, combined with the non-uniform deposition of Liions during plating at the anode surface, can seriously affect the performance, cycling, and safety of the battery. In addition, it has been suggested that a controlled SEI formation at the metallic Li anode can yield enhanced battery performance. Hence, a comprehensive understanding of how the SEI layer is formed can help elucidate improvements in this battery technology. In this work, the formation of the SEI layer in Li-S batteries is investigated using density functional theory (DFT) and ab initio molecular dynamics (AIMD) simulations. The stability of liquid organic-based electrolyte components, salt concentration, electron-rich environments, and the use of inorganic solid-state electrolyte (SSE) materials are explored in order to provide molecular-level fundamental insights into how the nature and composition of the electrolyte can alter the initial stages of the SEI formation. The products of electrolyte decomposition and electro-/chemical reaction pathways of liquid electrolyte component such as solvent and salts are predicted from AIMD simulations of electrolyte-anode interfaces. Energetics of reactions from DFT ground-state optimizations are also presented to confirm the decomposition mechanisms. Some significant differences are then drawn regarding the use of low and high salt concentrations. Simulations under electron-rich environments show additional multielectron electrochemical reactions of solvent and salt decomposition taking place due to the excess of electrons and the presence of radical anions in the solution. Finally, the initial stages of formation, stability, and main constituents of interfaces between Li-metal and Sbased electrodes with sulfide-based SSEs are characterized in detail.

25 ENERGY STORAGE↗
DOE OSTI2023

Cycling of block copolymer composites with lithium-conducting ceramic nanoparticles

Solid polymer and perovskite-type ceramic electrolytes have both shown promise in advancing solid-state lithium metal batteries. Despite their favorable interfacial stability against lithium metal, polymer electrolytes face issues due to their low ionic conductivity and poor mechanical strength. Highly conductive and mechanically robust ceramics, on the other hand, cannot physically remain in contact with redox-active particles that expand and contract during charge-discharge cycles unless excessive pressures are used. To overcome the disadvantages of each material, polymer-ceramic composites can be formed; however, depletion interactions will always lead to aggregation of the ceramic particles if a homopolymer above its melting temperature is used. In this study, we incorporate Li 0.33 La 0.56 TiO 3 (LLTO) nanoparticles into a block copolymer, polystyrene- b -poly (ethylene oxide) (SEO), to develop a polymer-composite electrolyte (SEO-LLTO). TEMs of the same nanoparticles in polyethylene oxide (PEO) show highly aggregated particles whereas a significant fraction of the nanoparticles are dispersed within the PEO-rich lamellae of the SEO-LLTO electrolyte. We use synchrotron hard x-ray microtomography to study the cell failure and interfacial stability of SEO-LLTO in cycled lithium-lithium symmetric cells. Three-dimensional tomograms reveal the formation of large globular lithium structures in the vicinity of the LLTO aggregates. Encasing the SEO-LLTO between layers of SEO to form a “sandwich” electrolyte, we prevent direct contact of LLTO with lithium metal, which allows for the passage of seven-fold higher current densities without signatures of lithium deposition around LLTO. We posit that eliminating particle clustering and direct contact of LLTO and lithium metal through dry processing techniques is crucial to enabling composite electrolytes.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2020

Biomimetic composite architecture achieves ultrahigh rate capability and cycling life of sodium ion battery cathodes

Sodium ion batteries are an emerging candidate to replace lithium ion batteries in large-scale electrical energy storage systems due to the abundance and widespread distribution of sodium. Despite the growing interest, the development of high-performance sodium cathode materials remains a challenge. In particular, polyanionic compounds are considered as a strong cathode candidate owing to their better cycling stability, a flatter voltage profile, and stronger thermal stability compared to other cathode materials. Here, we report the rational design of a biomimetic bone-inspired polyanionic Na3V2(PO4)3-reduced graphene oxide composite (BI-NVP) cathode that achieves ultrahigh rate charging and ultralong cycling life in a sodium ion battery. At a charging rate of 1 C, BI-NVP delivers 97% of its theoretical capacity and is able to retain a voltage plateau even at the ultra-high rate of 200 C. It also shows long cycling life with capacity retention of 91% after 10 000 cycles at 50 C. The sodium ion battery cells with a BI-NVP cathode and Na metal anode were able to deliver a maximum specific energy of 350 W h kg−1 and maximum specific power of 154 kW kg−1. In situ and postmortem analyses of cycled BI-NVP (including by Raman and XRD spectra) HRTEM, and STEM-EELS, indicate highly reversible dilation–contraction, negligible electrode pulverization, and a stable NVP-reduced graphene oxide layer interface. The results presented here provide a rational and biomimetic material design for the electrode architecture for ultrahigh power and ultralong cyclability of the sodium ion battery full cells when paired with a sodium metal anode.

25 ENERGY STORAGE↗
DOE OSTI2020

Toward a high-voltage fast-charging pouch cell with TiO 2 cathode coating and enhanced battery safety

Nickel-rich layered lithium transition metal oxides, LiNi x Co y Mn 1-x-y O 2 , are key cathode materials for high-energy lithium-ion batteries owing to their high specific capacity. However, the commercial deployment of nickel-rich oxides has been hampered by their poor thermostability and insufficient cycle life. In this work full batteries with uncoated and TiO 2 -coated LiNi 0.5 Co 0.2 Mn 0.3 O 2 cathodes and graphite anodes are compared in terms of electrochemical performance and safety behavior. The battery using a TiO 2 -coated LiNi 0.5 Co 0.2 Mn 0.3 O 2 cathode exhibited better cyclic performance at high cutoff voltage. Electrochemical impedance spectroscopy analysis indicated that the TiO 2 -coated LiNi 0.5 Co 0.2 Mn 0.3 O 2 cathode gave the battery a more stable charge transfer resistance. Transmission electron microscopy demonstrated that TiO 2 coating reduced accumulation of the cathode electrolyte interface layer on the particle surface. Time-of-flight secondary ion mass spectrometry demonstrated that TiO 2 coating markedly enhanced the interface stability of the cathode particle and protected the particle from serious etching by the electrolyte. Accelerating rate calorimetry revealed that the trigger temperature of thermal runaway for the battery using TiO 2 -coated LiNi 0.5 Co 0.2 Mn 0.3 O 2 as cathode material was 257 °C, which was higher than that of the battery with the uncoated LiNi 0.5 Co 0.2 Mn 0.3 O 2 cathode (251 °C). In situ X-ray diffraction during heating demonstrated that this enhanced safety can be attributed to the suppressed phase evolution of the coated cathode material.

25 ENERGY STORAGE↗