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At least 1,045 records · Page 58

Deconvoluting the impact of current collector structure and electrolyte selection on Coulombic efficiency of lithium metal anodes

Lithium metal batteries are regarded as a promising avenue for significantly boosting the gravimetric energy density of batteries, particularly for electric vehicles. However, the instability of the lithium metal anode continues to hinder performance. While 3D structured current collectors for lithium metal anodes have been frequently proposed as a solution, few studies explore the impact of these structures when combined with various electrolytes and the inclusion of a lithium reservoir within the structure. This study pairs four commercially available copper current collectors with four different electrolytes to assess how these factors influence cycling performance with a 4 mAh/cm2 lithium reservoir. Coulombic efficiency (CE) measurements revealed no statistically significant difference in CE across different current collectors within the same electrolyte. However, significant variations were noted when the current collector remained intact, and the electrolyte was changed. Although polarization, electrochemical impedance, and lithium morphology varied between structures and electrolytes, no consistent patterns emerged to suggest superior performance by any specific current collector structure. Therefore, the choice of structure appears inconsequential when a lithium reservoir is present, and efforts should focus on selecting and designing the electrolyte.

White, Julia↗

Electrochemo-mechanics unlocks hidden dynamics of lithium plating under stacking pressure

Understanding and mitigating lithium plating remains one of the most pressing challenges in advancing the safety and longevity of lithium-ion batteries (LIBs). Here, we present a novel integrative framework that combines in-operando swelling force measurements with a physics-based electro-chemo-mechanical model to uncover previously inaccessible insights into lithium plating dynamics under mechanical constraints. Unlike existing approaches that focus primarily on electrochemical signatures, our approach captures the coupled mechanical responses of commercial pouch cells during cycling, revealing how mechanical constraints fundamentally alter degradation pathways. We demonstrate that the use of a moderate stacking pressure suppresses lithium plating and enhances lithium stripping. This mechanically driven structural effect, coupled with the electrochemical process, significantly extends the linear aging regime in LIBs. Intriguingly, intermittent capacity recovery events that were observed during the battery cycling suggest dynamic lithium reactivation, a phenomenon rarely captured in real-time. This study pioneers a stress-aware methodology for diagnosing and managing lithium plating, establishing a new paradigm for real-time battery health monitoring. The findings offer transformative implications for the design of durable, high-performance LIB systems, opening new avenues for intelligent control strategies in battery management systems.

Bhowmick, Amit↗

In Situ NMR Observation of the Temporal Speciation of Lithium Sulfur Batteries during Electrochemical Cycling

The understanding of the reaction mechanism and temporal speciation of the lithium sulfur batteries is challenged by complex polysulfide disproportionation chemistry coupled with the precipitation and dissolution of species. In this report, for the first time, we present a comprehensive method to investigate lithium sulfur electrochemistry using in situ 7 Li NMR spectroscopy, a technique that is capable of quantitatively capturing the evolution of the soluble and precipitated lithium (poly)sulfides during electrochemical cycling. Furthermore, through deconvolution and quantification, every lithium-bearing species was closely tracked and four-step soluble lithium polysulfide-mediated lithium sulfur electrochemistry was demonstrated in never before seen detail. Significant irreversible accumulation of Li 2 S is observed on the Li metal anode after four cycles because of sulfur shuttling. We present the application of the method in order to study electrolyte/additive development and lithium protection research can be readily envisaged.

25 ENERGY STORAGE↗

Resistive Switching of Spinel Li 4 Ti 5 O 12 Lithium-Ion Battery Material for Neuromorphic Computing

The rapid rise of AI has exposed significant limitations in conventional Von Neumann computing architecture, particularly in regard to speed and energy efficiency. To address these challenges, researchers are exploring a brain-inspired neuromorphic architecture that mimics biological neural networks, enabling massive parallel processing with reduced power consumption for complex AI computational demands. Recent interest has focused on utilizing battery electrodes and solid electrolyte materials for their resistive switching properties in developing a neuromorphic architecture. These properties are precisely tuned through local- and bulk-level chemical composition modifications via voltage bias stimuli. In this study, we demonstrate fabricating a three-terminal lithium-ion electrochemical transistor based on lithium titanium oxide (Li 4 Ti 5 O 12 ), a popular lithium-ion battery anode material. We deposited and characterized LTO thin films using RF sputtering, demonstrating a 6 orders of magnitude increase in electronic conductivity upon lithiation, with conductivity plateauing after 20% lithiation. Density functional theory calculations revealed transformation from the insulating to conducting state, supported by experimental characterization through X-Ray Photoelectron Spectroscopy (XPS) and Direct Current (DC) polarization analyses. The fabricated transistor consisted of LTO as the channel layer, gold as source/drain terminals, lithium phosphorus oxynitride (LiPON) as the lithium-ion conductor, and copper as the gate terminal. The device exhibited clear hysteresis in transfer characteristics due to lithium insertion/extraction processes. Long-term potentiation (LTP) and long-term depression (LTD) measurements showed an asymmetric ratio of 1.425 and maximum/minimum conductance ratio of 7.83. When implemented in a deep neural network (DNN) for MNIST handwritten digit recognition, the device achieved 92.03% accuracy over 20 training epochs. Detailed transport mechanism analysis revealed the crucial role of oxygen vacancies and interface effects in device operation. Our preliminary findings establish LTO-based lithium-ion electrochemical transistors as promising candidates for energy-efficient neuromorphic computing applications, offering potential solutions to traditional Von Neumann architecture limitations.

25 ENERGY STORAGE↗

Mechanical rolling formation of interpenetrated lithium metal/lithium tin alloy foil for ultrahigh-rate battery anode

To achieve good rate capability of lithium metal anodes for high-energy-density batteries, one fundamental challenge is the slow lithium diffusion at the interface. Here we report an interpenetrated, three-dimensional lithium metal/lithium tin alloy nanocomposite foil realized by a simple calendering and folding process of lithium and tin foils, and spontaneous alloying reactions. The strong affinity between the metallic lithium and lithium tin alloy as mixed electronic and ionic conducting networks, and their abundant interfaces enable ultrafast charger diffusion across the entire electrode. Furthermore, we demonstrate that a lithium/lithium tin alloy foil electrode sustains stable lithium stripping/plating under 30 mA cm -2 and 5 mAh cm -2 with a very low overpotential of 20 mV for 200 cycles in a commercial carbonate electrolyte. Cycled under 6 C (6.6 mA cm -2 ), a 1.0 mAh cm -2 LiNi 0.6 Co 0.2 Mn 0.2 O 2 electrode maintains a substantial 74% of its capacity by pairing with such anode.

25 ENERGY STORAGE↗

Fast galvanic lithium corrosion involving a Kirkendall-type mechanism

Developing a viable metallic lithium anode is a prerequisite for next-generation batteries. However, the low redox potential of lithium metal renders it prone to corrosion, which must be thoroughly understood for it to be used in practical energy-storage devices. Here in this paper, we report a previously overlooked mechanism by which lithium deposits can corrode on a copper surface. Voids are observed in the corroded deposits and a Kirkendall-type mechanism is validated through electrochemical analysis. Although it is a long-held view that lithium corrosion in electrolytes involves direct charge-transfer through the lithium–electrolyte interphase, the corrosion observed here is found to be governed by a galvanic process between lithium and the copper substrate—a pathway largely neglected by previous battery corrosion studies. The observations are further rationalized by detailed analyses of the solid–electrolyte interphase formed on copper and lithium, where the disparities in electrolyte reduction kinetics on the two surfaces can account for the fast galvanic process.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Status and challenges in enabling the lithium metal electrode for high-energy and low-cost rechargeable batteries

Enabling the reversible lithium metal electrode is essential for surpassing the energy content of today’s lithium-ion cells. Although lithium metal cells for niche applications have been developed already, efforts are underway to create rechargeable lithium metal batteries that can significantly advance vehicle electrification and grid energy storage. In this Perspective, we focus on three tasks to guide and further advance the reversible lithium metal electrode. First, we summarize the state of research and commercial efforts in terms of four key performance parameters, and identify additional performance parameters of interest. We then advocate for the use of limited lithium (≤30 μm) to ensure early identification of technical challenges associated with stable and dendrite-free cycling and a more rapid transition to commercially relevant designs. Finally, we provide a cost target and outline material costs and manufacturing methods that could allow lithium metal cells to reach 100 US$ kWh–1.

25 ENERGY STORAGE↗

Uncovering the predictive pathways of lithium and sodium interchange in layered oxides

Ion exchange is a powerful method to access metastable materials with advanced functionalities for energy storage applications. However, high concentrations and unfavourably large excesses of lithium are always used for synthesizing lithium cathodes from parent sodium material, and the reaction pathways remain elusive. Here, using layered oxides as model materials, we demonstrate that vacancy level and its corresponding lithium preference are critical in determining the accessible and inaccessible ion exchange pathways. Taking advantage of the strong lithium preference at the right vacancy level, we establish predictive compositional and structural evolution at extremely dilute and low excess lithium based on the phase equilibrium between Li 0.94 CoO 2 and Na 0.48 CoO 2 . Such phase separation behaviour is general in both surface reaction-limited and diffusion-limited exchange conditions and is accomplished with the charge redistribution on transition metals. Guided by this understanding, we demonstrate the synthesis of Na y CoO 2 from the parent Li x CoO 2 and the synthesis of Li 0.94 CoO 2 from Na y CoO 2 at 1-1,000 Li/Na (molar ratio) with an electrochemical assisted ion exchange method by mitigating the kinetic barriers. Our study opens new opportunities for ion exchange in predictive synthesis and separation applications. Ion exchange is a powerful method to access metastable materials for energy storage, but identifying lithium and sodium interchange in layered oxides remains challenging. Using such model materials, vacancy level and corresponding lithium preference are shown to be crucial for ion exchange pathway accessibility.

25 ENERGY STORAGE↗

Overcoming misconceptions in lithium metal polymer electrolyte batteries

Uncovering the truth of lithium polymer batteries. Lithium metal is the holy grail of anodes due to its 10-fold higher gravimetric capacity than graphite. All-solid-state lithium polymer electrolyte batteries are receiving significant attention due to their increased flexibility compared to inorganic solid-state electrolytes, which enhances processability, accommodates cell swelling, and enables more homogeneous interphases. However, prototype solid-state lithium polymer electrolyte batteries have been limited in their usage due to the low ionic conductivity of the electrolyte, which limits their ability to cycle lithium metal at high rates. In this opinion, we provide alternative interpretations of high-rate capability lithium metal polymer electrolytes and breakthroughs in highly ionically conductive all-solid-state polymer electrolytes. In addition, we provide guidance on how to characterize and evaluate polymer electrolytes in lithium metal batteries.

Waugh, John B↗

Flexible, solid-state, ion-conducting membrane with 3D garnet nanofiber networks for lithium batteries

Beyond state-of-the-art lithium-ion battery (LIB) technology with metallic lithium anodes to replace conventional ion intercalation anode materials is highly desirable because of lithium’s highest specific capacity (3,860 mA/g) and lowest negative electrochemical potential (~3.040 V vs. the standard hydrogen electrode). In this work, we report for the first time, to our knowledge, a 3D lithium-ion–conducting ceramic network based on garnet-type Li 6.4 La 3 Zr 2 Al 0.2 O 12 (LLZO) lithium-ion conductor to provide continuous Li + transfer channels in a polyethylene oxide (PEO)-based composite. This composite structure further provides structural reinforcement to enhance the mechanical properties of the polymer matrix. The flexible solid-state electrolyte composite membrane exhibited an ionic conductivity of 2.5 × 10 -4 S/cm at room temperature. The membrane can effectively block dendrites in a symmetric Li | electrolyte | Li cell during repeated lithium stripping/plating at room temperature, with a current density of 0.2 mA/cm 2 for around 500 h and a current density of 0.5 mA/cm 2 for over 300 h. Finally, these results provide an all solid ion-conducting membrane that can be applied to flexible LIBs and other electrochemical energy storage systems, such as lithium–sulfur batteries.

25 ENERGY STORAGE↗

A dual membrane-adsorption evaporator for solar-powered lithium extraction from complex brines

A reliable supply of lithium is required to meet the increased demand for batteries over the coming decades. In this work, we demonstrated the potential to effectively extract lithium from brines by coupling solar-powered evaporation, adsorption, and membrane technologies together. We first synthesized a three-dimensional adsorptive evaporator by coating a lithium manganese oxide material onto a cotton stick using an easily scalable, one-step method. An osmotic membrane was then installed at the root of the evaporator to enhance the lithium to magnesium selectivity, prevent scaling caused by divalent cations, and thus further increase the water evaporation flux. The operation of the dual membrane-adsorption evaporator is entirely driven by osmosis and capillary force, demanding no extra energy input. The integration of the osmotic membrane was found to increase the lithium to magnesium selectivity over 10-fold to higher than 40. The dual process also produced high lithium to calcium selectivity and proved to sustain long-term stability by self-managing its internal osmotic pressure. Last, a test was done in three simulated brine solutions with varied brine chemistry and the evaporation rate stayed high and consistent throughout the long-term test. This illustrates that this technology can be used in varied brine solutions throughout the world providing efficient lithium capture and separation from competing divalent cations.

Eskafi, Aydin F. [University of California, Berkel↗

Use of Ethylene Carbonate Free Ester Solvent Systems with Alternative Lithium Salts for Improved Low-Temperature Performance in NCM622∣∣ Graphite Li-ion Batteries

An investigation of alternative lithium salts, lithium tetrafluoroborate (LiBF 4 ), lithium difluoro(oxalato)borate (LiDFOB) and lithium hexafluorophosphate (LiPF 6 ), in novel ester-based (methyl acetate/fluoroethylene carbonate- MA/FEC or methyl propionate/fluoroethylene carbonate- MP/FEC) electrolyte formulations has been conducted in LiNi 0.6 Co 0.2 Mn 0.2 O 2 (NCM622)/graphite cells to improve low temperature cycling performance of lithium ion batteries at −20 °C. Improved low temperature performance was observed with all the lithium salts in MA/FEC electrolyte while comparable room temperature (25 °C) capacities were observed with LiPF 6 salt only. Detailed ex-situ analysis of surface films generated with LiBF 4 , LiDFOB and LiPF 6 in ester-based electrolytes reveals that the solid electrolyte interphase (SEI) is predominately composed of lithium salt decompaction products and addition of 10% FEC (by volume%) may not be sufficient at forming a protective SEI.

25 ENERGY STORAGE↗

Particle control and plasma performance in the Lithium Tokamak eXperiment (LTX)

The Lithium Tokamak eXperiment (LTX) is a small, low aspect ratio tokamak, which is fitted with a stainless steel-clad copper liner, conformal to the last closed flux surface. The liner can be heated to 350°C. Several gas fueling systems, including supersonic gas injection, and molecular cluster injection have been studied, and produce fueling efficiencies up to 35%. Discharges are strongly affected by wall conditioning. Discharges without lithium wall coatings are limited to plasma currents of order 10 kA, and discharge durations of order 5 msec. With solid lithium coatings discharge currents exceed 70 kA, and discharge durations exceed 30 msec. Heating the lithium wall coating, however, results in a prompt degradation of the discharge, at the melting point of lithium. These results suggest that the simplest approach to implementing liquid lithium walls in a tokamak - thin, evaporated, liquefied coatings of lithium - does not produce an adequately clean surface.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗

Perfluoro Aryl Boronic Esters as Chemical Shuttle Additives in Lithium Ion Batteries

Redox shuttles could provide an added measure of control for lithium ion batteries beyond that which is provided by the battery management system. Redox shuttles, which are electrolyte additives, provide electrochemical overcharge protection. Since they possess a reduction-oxidation potential that is slightly above the maximum cathode potential during normal use, they should cause no degradation in cell performance during normal operation, but should shuttle excess electrons during overcharge conditions, effectively limiting the full cell voltage. The goals of the Chemical Shuttle Additives program were to discover and implement a redox shuttle that is compatible with large format lithium ion cells utilizing LiNi 1/3 Mn 1/3 Co 1/3 O 2 (NMC) cathode material and to understand the mechanism of redox shuttle action. Many redox shuttles, both commercially available and experimental, were tested and much fundamental information regarding the mechanism of redox shuttle action was discovered. In particular, studies surrounding the mechanism of the reduction of the oxidized redox shuttle at the carbon anode surface were particularly revealing. Shuttles that were evaluated in various lithium ion cell chemistries include: • 2-(pentafluorophenyl)-tetrafluoro-1,3,2-benzodioxaborole (BDB) supplied by Argonne National Laboratory (ANL), Lemont, Illinois; • 2,5-di-tert-butyl-1,4-dimethoxybenzene (DDB) supplied by 3M, St. Paul, Minnesota; • Li 2 B 12 F 12 supplied by Air Products, Allentown, Pennsylvania (pure compound) and Showa Denko, Japan (in electrolyte); • 1,4-bis(2-methoxyethoxy)-2,5-di-tert-butyl-benzene (ANL-RS2) supplied by Argonne National Laboratory (ANL), Lemont, Illinois; and • A 4.5V class redox shuttle supplied by Argonne National Laboratory (ANL), Lemont, Illinois Although redox shuttles with an appropriate redox potential and sufficient chemical and electrochemical stability for cells utilizing cathodes with potentials higher and lower than that of NMC, a redox shuttle that is viable for use in large format lithium ion cells with NMC cathodes was not found. The effect of the anode on the capacity loss of lithium ion cells with redox shuttles in cells utilizing lithium, lithium titanate, or graphite cells was studied. Molecular imprinting of the redox shuttle molecule during solid electrolyte interphase (SEI) layer formation likely contributes to the successful reduction of oxidized redox shuttle species at carbon anodes. This helps understand how a carbon anode covered with an SEI layer, that is supposed to be electrically insulating, can reduce the oxidized form of a redox shuttle.

25 ENERGY STORAGE↗

Large-Area Lithium Electrode Sub-Assemblies (LESAs) Protected by Self Forming Microstructured Polymer-Inorganic Single-Ion Conducting Composites (Final Report)

The aim of this project is to realize a low-cost, safe, reversible, high-areal capacity lithium metal electrode though the use of scalable, low-cost Lithium Electrode Sub-Assembly (LESA). At its core, the LESA applies novel polymer scaffolds to nanostructure inorganic ionic materials into high-conductivity composites that stabilize lithium anodes during high-rate, high-capacity cycling in lithium metal batteries. Fundamental investigations from this project identified a newly defined region of stability for composites with respect to the shear modulus and lithium molar volume ratio which have been broadly applied in the scientific literature for a multitude of different systems. The advancements achieved in this field have furthered the fundamental understanding of lithium metal electrode chemistry and degradation mechanisms and resulted in a lithium metal anode with improved cycle life.

25 ENERGY STORAGE↗

Degradation and recovery mechanisms in lithium-doped solar cells

Several groups of lithium-doped solar cells have been evaluated under 1-MeV electron irradiation. Many of these groups indicated superior electrical output after irradiation and recovery as compared to similarly irradiated n/p solar cells. The superior cells are those with lithium concentrations of 2 to 5 x 10 to the 14th power atoms per cu cm at the junction. An irradiation of lithium-doped cells with 28-MeV electrons indicated a tenfold advantage of lithium-doped cells over n/p cells. Studies of the changes in the lithium concentration during recovery have shown the amounts of lithium reacting is highly nonlinear in regard to the electron fluence and varies greatly with distance from the junction. The results indicate that precipitation of lithium on radiation defects may be the cause of recovery rather than ion pairing.

Downing, R. G.↗

JPL lithium doped solar cell development program

One of the most significant problems encountered in the use of silicon solar cells in space is the sensitivity of the device to electron and proton radiation exposure. The p-diffused-into-n-base solar cells were replaced with the more radiation tolerant n-diffused-into-p-base solar cells. Another advancement in achieving greater radiation tolerance was the discovery that the addition of lithium to n-base silicon resulted in what appeared to be annealing of radiation-induced defects. This phenomenon is being exploited to develop a high efficiency radiation resistant lithium-doped solar cell. Lithium-doped solar cells fabricated from oxygen-lean and oxygen-rich silicon were obtained with average initial efficiencies of 11.9% at air mass zero and 28 C, as compared to state-of-the-art n-p cells fabricated from 10 ohm cm silicon with average efficiencies of 11.3% under similar conditions. Lithium-doped cells demonstrated the ability to withstand three to five times the fluence of 1-MeV electrons before degrading to a power equivalent to state-of-the-art solar cells. The principal investigations are discussed with respect to fabrication of high efficiency radiation resistant lithium-doped cells, including starting material, p-n junction diffusion, lithium source introduction, and lithium diffusion.

Berman, P. A.↗

Research, Development and Fabrication of Lithium Solar Cells, Part 2

The development and fabrication of lithium solar cells are discussed. Several single-step, lithium diffusion schedules using lower temperatures and times are described. A comparison was made using evaporated lithium metal as the lithium source, and greatly improved consistency in lithium concentrations was obtained. It was possible to combine all processing steps to obtain lithium doped cells of high output which also contained adequate lithium to ensure good recoverability.

Iles, P. A.↗