Search

Lithium-ion batteries are currently one of the most important energy storage devices for various applications. However, it remains a great challenge to achieve both high energy density and high-power density while reducing the production costs. Cells with three-dimensional electrodes realized by laser ablation are proven to have enhanced electrochemical performance compared to those with conventional two-dimensional electrodes, especially at fast charging/discharging. Nevertheless, laser structuring of electrodes is still limited in terms of achievable processing speed, and the upscaling of the laser structuring process is of great importance to gain a high technology readiness level. In the presented research, the impact of different laser structuring strategies on the electro-chemical performance was investigated on aqueous processed Li(Ni0.6Mn0.2Co0.2)O2 cathodes with acid addition during the slurry mixing process. Rate capability analyses of cells with laser structured aqueous processed electrodes exhibited enhanced performance with capacity increases of up to 60 mAh/g at high current density, while a 65% decrease in ionic resistance was observed for cells with laser structured electrodes. In addition, pouch cells with laser structured acid-added electrodes maintained 29–38% higher cell capacity after 500 cycles and their end-of-life was extended by a factor of about 4 in contrast to the reference cells with two-dimensional electrodes containing common organic solvent processed polyvinylidene fluoride binder. [ABSTRACT FROM AUTHOR]

The lithium–sulfur (Li–S) battery system has attracted considerable attention due to its ultrahigh theoretical energy density and promising applications. However, with the increasing demands on S loading and electrolyte content, practical Li–S batteries still face several serious challenges, such as slow reaction kinetics at the cathode interface, unstable anode interface reactions, and undesirable crosstalk effects between the cathode and anode. Traditional electrolyte systems often struggle to address these challenges under practical conditions, thereby rendering it imperative to establish a new electrolyte system for practical Li–S batteries. This review first discusses the necessity of establishing a new electrolyte and propose specific parameter requirements, such as the electrolyte‐to‐sulfur mass ratio (Em/S). Subsequently, some electrolyte modification strategies proposed by researchers are summarized to address the different challenges associated with practical Li–S batteries. Finally, the combination of different strategies is reviewed, aiming to reveal more effective design approaches that simultaneously address multiple challenges, while providing guidance for establishing a new balanced electrolyte for practical Li–S batteries. This article promotes the development of new electrolytes for practical Li–S batteries and can act as a reference for the development of electrolytes for other secondary batteries. [ABSTRACT FROM AUTHOR]

Highlights FGN-182 electrolytes exhibit highly reversible Li plating/stripping with an average Coulombic efficiency reaching up to 99.56% determined from Auerbach’s test. The gas-evolution process of LiNO3 in high-voltage lithium cobalt oxide (LCO) cathodes is revealed by in situ differential electrochemical mass spectrometry. Pouch cells equipped with high-loading LCO (3 mAh cm−2) cathodes, ultrathin Li chips (25 μm), and lean electrolytes (5 g Ah−1) using optimized electrolyte (FGN-182 + 1%HTCN) demonstrate outstanding cycling performance.

All‐solid‐state batteries are emerging as potential successors in energy storage technologies due to their increased safety, stemming from replacing organic liquid electrolytes in conventional Li‐ion batteries with less flammable solid‐state electrolytes. However, all‐solid‐state batteries require precise control over cycling pressure to maintain effective interfacial contacts between materials. Traditional uniaxial cell holders, often used in battery research, face challenges in accommodating electrode volume changes, providing uniform pressure distribution, and maintaining consistent pressure over time. This study introduces isostatic pouch cell holders utilizing air as pressurizing media to achieve uniform and accurately regulated cycling pressure. LiNi0.8Co0.1Mn0.1O2 | Li6PS5Cl | Si pouch cells are fabricated and tested under 1 to 5 MPa pressures, revealing improved electrochemical performance with higher cycling pressures, with 2 MPa as the minimum for optimal operation. A bilayer pouch cell with a theoretical capacity of 100 mAh, cycled with an isostatic pouch cell holder, demonstrated a first‐cycle Coulombic efficiency of 76.9% and a discharge capacity of 173.6 mAh g−1 (88.1 mAh), maintaining 83.6% capacity after 100 cycles. These findings underscore the effectiveness of isostatic pouch cell holders in enhancing the performance and practical application of all‐solid‐state batteries. [ABSTRACT FROM AUTHOR]

Lithium–sulfur batteries with liquid electrolytes are discussed as the most promising post‐lithium‐ion‐battery technology in literature due to their high theoretical specific energy and first prototype cells delivering >470 Wh kg−1. Although several electrolyte and material concepts are developed that partially solve the issue of the so‐called shuttle mechanism, the most promising concept to genuinely confine sulfur species in the cathode is all‐solid‐state argyrodite–sulfur cathodes leading to almost theoretical active material utilization by maintaining reasonable sulfur loadings and electrolyte to sulfur ratios. However, this battery concept has so far not achieved reversible cycling against metallic lithium anodes as it requires high pressures for manufacturing, and ductile lithium metal creeps along the grain boundaries of the solid electrolyte particles leading to short cuts of the cells. Recent findings show that metallic lithium, however, can be stably cycled with dimethoxyethane/lithium‐bis(fluorosulfonyl)imide (DME/LiFSI)‐based electrolytes. Herein, for the first time, a semisolid concept is presented combining the benefits of an argyrodite‐based solid‐state cathode and a DME/LiFSI/hydrofluoroether‐based anolyte concept – in coin cells and first pouch cells. This disruptive approach enables projected specific energies higher than 600 Wh kg−1 at cell stack level. [ABSTRACT FROM AUTHOR]

Highlights: FGN-182 electrolytes exhibit highly reversible Li plating/stripping with an average Coulombic efficiency reaching up to 99.56% determined from Auerbach's test. The gas-evolution process of LiNO3 in high-voltage lithium cobalt oxide (LCO) cathodes is revealed by in situ differential electrochemical mass spectrometry. Pouch cells equipped with high-loading LCO (3 mAh cm−2) cathodes, ultrathin Li chips (25 μm), and lean electrolytes (5 g Ah−1) using optimized electrolyte (FGN-182 + 1%HTCN) demonstrate outstanding cycling performance. The lithium (Li) metal anode is widely regarded as an ideal anode material for high-energy-density batteries. However, uncontrolled Li dendrite growth often leads to unfavorable interfaces and low Coulombic efficiency (CE), limiting its broader application. Herein, an ether-based electrolyte (termed FGN-182) is formulated, exhibiting ultra-stable Li metal anodes through the incorporation of LiFSI and LiNO3 as dual salts. The synergistic effect of the dual salts facilitates the formation of a highly robust SEI film with fast Li+ transport kinetics. Notably, Li||Cu half cells exhibit an average CE reaching up to 99.56%. In particular, pouch cells equipped with high-loading lithium cobalt oxide (LCO, 3 mAh cm−2) cathodes, ultrathin Li chips (25 μm), and lean electrolytes (5 g Ah−1) demonstrate outstanding cycling performance, retaining 80% capacity after 125 cycles. To address the gas issue in the cathode under high voltage, cathode additives 1,3,6-tricyanohexane is incorporated with FGN-182; the resulting high-voltage LCO||Li (4.4 V) pouch cells can cycle steadily over 93 cycles. This study demonstrates that, even with the use of ether-based electrolytes, it is possible to simultaneously achieve significant improvements in both high Li utilization and electrolyte tolerance to high voltage by exploring appropriate functional additives for both the cathode and anode. [ABSTRACT FROM AUTHOR]

The gas release within Li‐ion batteries, particularly during cycling and storage, can result in rapid performance degradation and potential safety hazards. However, this area has not garnered sufficient attention until now, primarily because the gassing information collected by typical OEMS/DEMS is quite limited and even inaccurate. Herein, for the first time, a state‐of‐the‐art on‐line GC‐BID/MS to full‐dimensionally analyze the gassing behavior within both lab‐scale coin‐type cell (in situ mode) and industry‐scale pouch‐type cell (operando mode) is originally designed/constructed. Not limited to common permanent gases (e.g. H2, CO, etc.) detected by online GC‐BID, but also complicated/various (semi‐)volatile products are identified/quantified by online GC‐MS. Based on the real‐time evolution information of water, alcohols, aldehydes, ethers, esters, and hydrocarbons, the decomposition mechanisms of electrolyte on both graphite anode and/or LCO cathode sides is further supplemented/perfected. Moreover, at the level of the device, series derivative/crosstalk reactions induced by trapped/accumulated gaseous species are unveiled in practical pouch‐cell. [ABSTRACT FROM AUTHOR]

Highlights Ultra-thin asymmetric composite solid-state electrolytes with ultralight areal density were designed for solid-state lithium metal batteries, achieving interfacial stability to Li metal and high-voltage cathode. The improved mechanical properties of the electrolyte contribute to the inhibition of Li dendrite growth was demonstrated by both experimental and theoretical simulations. The assembled pouch cell exhibited a high gravimetric/volume energy density of 344.0 Wh kg−1/773.1 Wh L−1.

Battery materials research is of crucial importance to the development of next‐generation batteries. However, the transition from lab‐scale studies, typically in gram quantities, to industrially relevant ones (i.e., kilogram scale) has been holding back by challenges in scale‐up synthesis and a lack of reliable approaches to verify the electrochemical performance of the lab‐made materials. Here the design and assembly procedures of sub‐Ah‐scale pouch cells that provide validations of several lab‐made Li‐ion and Na‐ion cathode materials available in a limited quantity (<5 g) are reported. These lab‐made pouch cells show superior cycle stability and consistency over the widely used coin cells, exemplified by multiple Ni‐rich layered oxide‐graphite full batteries retaining 84.29 ± 0.16% of the initial capacities over 1000 cycles. A four‐electrode pouch cell with a reparable reference electrode is further designed to monitor impedance growth and Li plating during long‐term electrochemical tests. It can be further integrated with in situ ultrasonic imaging to enable multi‐modal studies. This work provides a powerful platform to evaluate and boost the technology readiness levels of laboratory‐discovered battery materials. [ABSTRACT FROM AUTHOR]

Highlights: Ultra-thin asymmetric composite solid-state electrolytes with ultralight areal density were designed for solid-state lithium metal batteries, achieving interfacial stability to Li metal and high-voltage cathode. The improved mechanical properties of the electrolyte contribute to the inhibition of Li dendrite growth was demonstrated by both experimental and theoretical simulations. The assembled pouch cell exhibited a high gravimetric/volume energy density of 344.0 Wh kg−1/773.1 Wh L−1. Solid-state lithium metal batteries (SSLMBs) show great promise in terms of high-energy–density and high-safety performance. However, there is an urgent need to address the compatibility of electrolytes with high-voltage cathodes/Li anodes, and to minimize the electrolyte thickness to achieve high-energy–density of SSLMBs. Herein, we develop an ultrathin (12.6 µm) asymmetric composite solid-state electrolyte with ultralight areal density (1.69 mg cm−2) for SSLMBs. The electrolyte combining a garnet (LLZO) layer and a metal organic framework (MOF) layer, which are fabricated on both sides of the polyethylene (PE) separator separately by tape casting. The PE separator endows the electrolyte with flexibility and excellent mechanical properties. The LLZO layer on the cathode side ensures high chemical stability at high voltage. The MOF layer on the anode side achieves a stable electric field and uniform Li flux, thus promoting uniform Li+ deposition. Thanks to the well-designed structure, the Li symmetric battery exhibits an ultralong cycle life (5000 h), and high-voltage SSLMBs achieve stable cycle performance. The assembled pouch cells provided a gravimetric/volume energy density of 344.0 Wh kg−1/773.1 Wh L−1. This simple operation allows for large-scale preparation, and the design concept of ultrathin asymmetric structure also reveals the future development direction of SSLMBs. [ABSTRACT FROM AUTHOR]

Transitioning to more ambitious electrode formulations facilitates developing high-energy density cells, potentially fulfilling the demands of electric car manufacturers. In this context, the partial replacement of the prevailing anode active material in lithium-ion cells, graphite, with silicon-based materials enhances its capacity. Nevertheless, this requires adapting the rest of the components and harmonizing the electrode integration in the cell to enhance the performance of the resulting high-capacity anodes. Herein, starting from a replacement in the standard graphite anode recipe with 22% silicon suboxide at laboratory scale, the weight fraction of the electrochemically inactive materials was optimized to 2% carbon black/1% dispersant/3% binder combination before deriving an advantage from including single-wall carbon nanotubes in the formulation. In the second part, the recipe was upscaled to a semi-industrial electrode coating and cell assembly line. Then, 1 Ah lithium-ion pouch cells were filled and tested with different commercial electrolytes, aiming at studying the dependency of the Si-based electrodes on the additives included in the composition. Among all the electrolytes employed, the EL2 excelled in terms of capacity retention, obtaining a 48% increase in the number of cycles compared to the baseline electrolyte formulation above the threshold capacity retention value (80% state of health). [ABSTRACT FROM AUTHOR]

Lithium–sulfur (Li–S) batteries promise high‐energy‐density potential to exceed the commercialized lithium‐ion batteries but suffer from limited cycling lifespan due to the side reactions between lithium polysulfides (LiPSs) and Li metal anodes. Herein, a three‐way electrolyte with ternary solvents is proposed to enable high‐energy‐density and long‐cycling Li–S pouch cells. Concretely, ternary solvents composed of 1,2‐dimethoxyethane, di‐isopropyl sulfide, and 1,3,5‐trioxane are employed to guarantee smooth cathode kinetics, inhibit the parasitic reactions, and construct a robust solid electrolyte interphase, respectively. The cycling lifespan of Li–S coin cells with 50 µm Li anodes and 4.0 mg cm−2 sulfur cathodes is prolonged from 88 to 222 cycles using the three‐way electrolyte. Nano‐heterogeneous solvation structure of LiPSs and organic‐rich solid electrolyte interphase are identified to improve the cycling stability of Li metal anodes. Consequently, a 3.0 Ah‐level Li–S pouch cell with the three‐way electrolyte realizes a high energy density of 405 Wh kg−1 and undergoes 27 cycles. This work affords a three‐way electrolyte recipe for suppressing the side reactions of LiPSs and inspires rational electrolyte design for practical high‐energy‐density and long‐cycling Li–S batteries. [ABSTRACT FROM AUTHOR]

Understanding mechanical failure modes of Li-ion battery electrodes of varying sizes and capacities is crucially important for the development of mechanically robust and high energy density flexible lithium-ion batteries (FLIBs). Three types of pouch cells (nominal capacities of 15, 25, and 50 mAh) were examined to understand how various design features used in the cells affected their mechanical failure modes and electrochemical performance after repeated introduction of compression and tension during bending. Postmortem microstructure analysis was carried out to identify the impacts of repeated flexing; several failure modes such as crack propagation, particle detachment, composite delamination, separator damage, electrode tears, and micro-short circuits were observed. We find that the observed mechanical failure modes are mainly dependent on the: 1) size and shape of the electrode composite materials, 2) configuration of the components within the cell (e.g., method of electrode folding, location of welded tabs), and 3) orientation of the long axis of the cell with respect to the bending axis. It was observed that the discharge capacity for all cell types studied herein was only slightly decreased (~6-7% at 2C-rate) even after 3,000 repeated bends at a 25mmradius of curvature provided if the bending axis is aligned to the long dimension of the cell. The results of this study provide valuable information on possible failure modes in Li-ion battery electrodes subjected to repeated flexing and how they can be mitigated to improve the dependability of practical pouch cells for FLIBs. [ABSTRACT FROM AUTHOR]

Lithium-ion batteries are currently one of the most important energy storage devices for various applications. However, it remains a great challenge to achieve both high energy density and high-power density while reducing the production costs. Cells with three-dimensional electrodes realized by laser ablation are proven to have enhanced electrochemical performance compared to those with conventional two-dimensional electrodes, especially at fast charging/discharging. Nevertheless, laser structuring of electrodes is still limited in terms of achievable processing speed, and the upscaling of the laser structuring process is of great importance to gain a high technology readiness level. In the presented research, the impact of different laser structuring strategies on the electro-chemical performance was investigated on aqueous processed Li(Ni0.6Mn0.2Co0.2)O2 cathodes with acid addition during the slurry mixing process. Rate capability analyses of cells with laser structured aqueous processed electrodes exhibited enhanced performance with capacity increases of up to 60 mAh/g at high current density, while a 65% decrease in ionic resistance was observed for cells with laser structured electrodes. In addition, pouch cells with laser structured acid-added electrodes maintained 29–38% higher cell capacity after 500 cycles and their end-of-life was extended by a factor of about 4 in contrast to the reference cells with two-dimensional electrodes containing common organic solvent processed polyvinylidene fluoride binder.

Lithium–sulfur batteries (LSBs) currently face challenges including lithium polysulfide shuttling, sluggish sulfur redox kinetics, severe lithium dendrite growth, and volume change. Herein, an advanced dual‐functional host is designed by embedding 3D N‐doped carbon fibers with abundant 2D V2CTx nanosheets (N/CF@V2CTx). The N‐doped carbon fibers act as "thread" to connect the V2CTx nanosheets and form a unique open 3D macroporous structure. This structure effectively prevents the restacking of the V2CTx nanosheets and exposes their lithiophilic and sulfurophilic sites. Consequently, the N/CF@V2CTx host effectively suppresses the shuttling of LiPSs and improves the cathodic kinetics. Furthermore, the 3D‐ordered porous skeleton integrated with abundant lithophilic sites enables uniform Li deposition and homogeneous Li‐ion flux, thereby inhibiting dendrite growth and mitigating volume expansion. The as‐assembled LSBs exhibit excellent rate capability (640 mAh g−1 at 15 C) and outstanding cycling stability (0.019% capacity decay per cycle throughout 1200 cycles at 1 C). Moreover, the pouch cell assembled with the N/CF@V2CTx host demonstrates a high energy density of 350 Wh kg−1 and good cycling stability. This research presents a promising approach to address the challenges of both the sulfur cathode and the lithium anode comprehensively and effectively in working LSBs. [ABSTRACT FROM AUTHOR]

Lithium–sulfur (Li–S) batteries promise great potential as high‐energy‐density energy storage devices. However, the parasitic reactions between lithium polysulfides (LiPSs) and Li metal anodes render limited cycling lifespan of Li–S batteries. Herein, an organic‐rich solid electrolyte interphase (SEI) is constructed to inhibit the LiPS parasitic reactions and achieve long‐cycling Li–S batteries. Concretely, 1,3,5‐trioxane is introduced as a reactive co‐solvent that decomposes on Li anode surfaces and contributes organic components to the SEI. The as‐constructed organic‐rich SEI effectively inhibits the LiPS parasitic reactions and protects working Li metal anodes. Consequently, the cycling lifespan of Li–S coin cells with 50 µm Li anodes and 4.0 mg cm−2 sulfur cathodes is prolonged from 130 to 300 cycles by the organic‐rich SEI. Furthermore, the organic‐rich SEI enables a 3.0 Ah‐level Li–S pouch cell to achieve a high energy density of 400 Wh kg−1 and stable 26 cycles. This study affords an effective organic‐rich SEI to inhibit the LiPS parasitic reactions and inspires rational SEI design to achieve long‐cycling Li–S batteries. [ABSTRACT FROM AUTHOR]

The growing requirements for electrified applications entail exploring alternative battery systems. Lithium‐sulfur batteries (LSBs) have emerged as a promising, cost‐effective, and sustainable solution; however, their practical commercialization is impeded by several intrinsic challenges. With the aim of surpassing these challenges, the implementation of a holistic LSB concept is proposed. To this end, the effectiveness of coupling a high‐performing 2D graphene‐based sulfur cathode with a well‐suited sparingly solvating electrolyte (SSE) is reported. The incorporation of bis(fluorosulfonyl)imide (LiFSI) salt to tune sulfolane and 1,1,2,2‐tetrafluoroethyl‐2,2,3,3‐tetrafluoropropylether based SSE enables the formation of a robust and compact lithium fluoride‐rich solid electrolyte interphase. Consequently, the lithium compatibility is improved, achieving a high Coulombic efficiency (CE) of 98.8% in the Li||Cu cells and enabling thin and dense lithium depositions. When combined with a high‐performing 2D graphene‐based sulfur cathode, a symbiotic effect is shown, leading to high discharge capacities, remarkable rate capability (2.5 mAh cm−2 at C/2), enhanced cell stability, and wide temperature applicability. Furthermore, the scalability of this strategy is successfully demonstrated by assembling high‐performing monolayer prototype cells with a total capacity of 93 mAh, notable capacity retention of 70% after 100 cycles, and a high average CE of 99%. [ABSTRACT FROM AUTHOR]

The sluggish kinetics of complicated multiphase conversions and the severe shuttling effect of lithium polysulfides (LiPSs) significantly hinder the applications of Li‐S battery, which is one of the most promising candidates for the next‐generation energy storage system. Herein, a bifunctional electrocatalyst, indium phthalocyanine self‐assembled with carbon nanotubes (InPc@CNT) composite material, is proposed to promote the conversion kinetics of both reduction and oxidation processes, demonstrating a bidirectional catalytic effect on both nucleation and dissolution of Li2S species. The theoretical calculation shows that the unique electronic configuration of InPc@CNT is conducive to trapping soluble polysulfides in the reduction process, as well as the modulation of electron transfer dynamics also endows the dissolution of Li2S in the oxidation reaction, which will accelerate the effectiveness of catalytic conversion and facilitate sulfur utilization. Moreover, the InPc@CNT modified separator displays lower overpotential for polysulfide transformation, alleviating polarization of electrode during cycling. The integrated spectroscopy analysis, HRTEM, and electrochemical study reveal that the InPc@CNT acts as an efficient multifunctional catalytic center to satisfy the requirements of accelerating charging and discharging processes. Therefore, the Li–S battery with InPc@CNT‐modified separator obtains a discharge‐specific capacity of 1415 mAh g−1 at a high rate of 0.5 C. Additionally, the 2 Ah Li–S pouch cells deliver 315 Wh kg−1 and achieved 80% capacity retention after 50 cycles at 0.1 C with a high sulfur loading of 10 mg cm−2. Our study provides a practical method to introduce bifunctional electrocatalysts for boosting the electrochemical properties of Li–S batteries. [ABSTRACT FROM AUTHOR]

The identification and location of critical defects inside battery cells before the performance decreases or safety issues arise remain a challenge. This study compares two nondestructive testing methods for the 3D visualization of defects at different depths inside a pouch battery cell: scanning acoustic microscopy (SAM) and X‐ray computed tomography (CT). A manufactured pouch cell with eight electrode sheets is used for this investigation. SAM using a 15 MHz transducer in reflection mode can detect defects at depths of up to four electrode sheets with a lateral resolution of 150 μm in 2 min. CT can locate defects on all eight stacked electrode sheets inside the pouch cell. The CT measurements take about 12.5 h. Both methods can complement each other in detecting defects inside thin pouch cells as an end‐of‐line test after the production or for qualifying individual battery cells for second‐life applications. As an in‐line quality check, SAM has proven to be a cost‐effective and efficient method for detecting defects such as misalignment on stacked electrodes. Both methods have the potential to expand the portfolio of nondestructive quality assurance tests in the production of lithium‐ion battery cells. This contributes to increasing the safety and productivity of battery technology. [ABSTRACT FROM AUTHOR]

Rational electrolyte design is essential for stabilizing high-energy-density lithium (Li) metal batteries but is plagued by poor understanding on the effect of electrolyte component properties on solvation structure and interfacial chemistry. Herein, regulating the solvation structure in localized high-concentration electrolytes (LHCE) by weakening the solvating power of solvents is proposed for high-performance LHCE. 1,3-dimethoxypropane (DMP) solvent has relatively weak solvating power but maintains the high solubility of Li salts, thus impelling the formation of nanometric aggregates where an anion coordinates to more than two Li-ions (referred to AGG-n) in LHCE. The decomposition of AGG-n increases the LiF content in solid electrolyte interphase (SEI), further enabling uniform Li deposition. The cycle life of Li metal batteries with DMP-based LHCE is 2.1 times (386 cycles) as that of advanced ether-based LHCE under demanding conditions. Furthermore, a Li metal pouch cell of 462 Wh kg−1 undergoes 58 cycles with the DMP-based LHCE pioneeringly. This work inspires ingenious solvating power regulation to design high-performance electrolytes for practical Li metal batteries. [ABSTRACT FROM AUTHOR]

Abstract Lithium–sulfur (Li–S) batteries promise high‐energy‐density potential to exceed the commercialized lithium‐ion batteries but suffer from limited cycling lifespan due to the side reactions between lithium polysulfides (LiPSs) and Li metal anodes. Herein, a three‐way electrolyte with ternary solvents is proposed to enable high‐energy‐density and long‐cycling Li–S pouch cells. Concretely, ternary solvents composed of 1,2‐dimethoxyethane, di‐isopropyl sulfide, and 1,3,5‐trioxane are employed to guarantee smooth cathode kinetics, inhibit the parasitic reactions, and construct a robust solid electrolyte interphase, respectively. The cycling lifespan of Li–S coin cells with 50 µm Li anodes and 4.0 mg cm−2 sulfur cathodes is prolonged from 88 to 222 cycles using the three‐way electrolyte. Nano‐heterogeneous solvation structure of LiPSs and organic‐rich solid electrolyte interphase are identified to improve the cycling stability of Li metal anodes. Consequently, a 3.0 Ah‐level Li–S pouch cell with the three‐way electrolyte realizes a high energy density of 405 Wh kg−1 and undergoes 27 cycles. This work affords a three‐way electrolyte recipe for suppressing the side reactions of LiPSs and inspires rational electrolyte design for practical high‐energy‐density and long‐cycling Li–S batteries.

Monitoring and diagnosing the battery status in real‐time are of utmost importance for clarifying failure mechanism, improving battery performance, and ensuring safety, particularly under fast charging conditions. Recently, advanced operando techniques have been developed to observe changes in the microstructures of lithium deposits using laboratory‐scale cell designs, focusing on understanding the nature of Li metal electrodes. However, the macroscopic spatial inhomogeneity of lithium electroplating/stripping in the prototype pressurized pouch cells has not been measured in real‐time under practical conditions. Herein, a new noninvasive operando technique, spatial pressure mapping analysis, is introduced to macroscopically and quantitatively measure spatial pressure changes in a pressurized pouch cell during cycling. Moreover, dynamic spatial changes in the macroscopic morphology of the lithium metal electrode are theoretically visualized by combining operando pressure mapping data with mechanical analyses of cell components. Additionally, under fast charging conditions, the direct correlation between abrupt capacity fading and sudden increases in spatial pressure distribution inhomogeneity is demonstrated through comparative analysis of pouch cells under various external pressures, electrolyte species, and electrolyte weight to cell capacity (e/c) ratios. This operando technique provides insights for assessing the current battery status and understanding the complex origin of cell degradation behavior in pressurized pouch cells. [ABSTRACT FROM AUTHOR]

Lithium–sulfur (Li–S) batteries are widely regarded as promising next‐generation battery systems due to their impressive theoretical energy density of 2600 Wh kg−1. However, practical high‐energy‐density Li–S pouch cells suffer from rapid performance degradation under high working rates. Herein, the performance degradation mechanism of 400 Wh kg−1 Li–S pouch cells is systematically investigated under a high cycling rate of 0.2 C. Focusing on the reduced specific capacity and increased cell polarization, the sluggish cathodic sulfur redox kinetics under lean‐electrolyte and high‐rate conditions is identified as the main limitation. Further polarization decoupling indicates the cathodic activation polarization contributes dominantly to the increased cell polarization. Accordingly, a delicately designed electrolyte using dimethyl diselenide as the kinetic promoter is proposed to enable the Li–S pouch cells to work at 0.2 C with reduced cell polarization. This work clarifies the sluggish cathodic interfacial charge transfer kinetics as the main challenge for high‐energy‐density Li–S batteries at high rates and is expected to inspire rational strategy design for achieving advanced Li–S batteries. [ABSTRACT FROM AUTHOR]

High-voltage spinel LiNi0.5Mn1.5O4 (LNMO) is a promising candidate as a lithium-ion battery cathode material to fulfill the high-energy density demands of the electric vehicle industry. In this work, the design of the experiment's methodology has been used to analyze the influence of the ratio of the different components in the electrode preparation feasibility of laboratory-scale coatings and their electrochemical response. Different outputs were defined to evaluate the formulations studied, and Derringer–Suich's methodology was applied to obtain an equation that is usable to predict the desirability of the electrodes depending on the selected formulation. Afterward, Solver's method was used to figure out the formulation that provides the highest desirability. This formulation was validated at a laboratory scale and upscaled to a semi-industrial coating line. High-voltage 1 Ah lithium-ion pouch cells were assembled with LNMO cathodes and graphite-based anodes and subjected to rate-capability tests and galvanostatic cycling. 1 C was determined as the highest C-rate usable with these cells, and 321 and 181 cycles above 80% SOH were obtained in galvanostatic cycling tests performed at 0.5 C and 1 C, respectively. Furthermore, it was observed that the LNMO cathode required an activation period to become fully electrochemically active, which was shorter when cycled at a lower C-rate. [ABSTRACT FROM AUTHOR]

Lithium–sulfur (Li−S) batteries are promising due to ultrahigh theoretical energy density. However, their cycling lifespan is crucially affected by the electrode kinetics of lithium polysulfides. Herein, the polysulfide solvation structure is correlated with polysulfide electrode kinetics towards long‐cycling Li−S batteries. The solvation structure derived from strong solvating power electrolyte induces fast anode kinetics and rapid anode failure, while that derived from weak solvating power electrolyte causes sluggish cathode kinetics and rapid capacity loss. By contrast, the solvation structure derived from medium solvating power electrolyte balances cathode and anode kinetics and improves the cycling performance of Li−S batteries. Li−S coin cells with ultra‐thin Li anodes and high‐S‐loading cathodes deliver 146 cycles and a 338 Wh kg−1 pouch cell undergoes stable 30 cycles. This work clarifies the relationship between polysulfide solvation structure and electrode kinetics and inspires rational electrolyte design for long‐cycling Li−S batteries. [ABSTRACT FROM AUTHOR]

The stability of high‐energy‐density lithium metal batteries depends on the uniformity of solid electrolyte interphase (SEI) on lithium metal anodes. Rationally improving SEI uniformity is hindered by poorly understanding the effect of structure and components of SEI on its uniformity. Herein, a bilayer structure of SEI formed by isosorbide dinitrate (ISDN) additives in localized high‐concentration electrolytes was demonstrated to improve SEI uniformity. In the bilayer SEI, LiNxOy generated by ISDN occupies top layer and LiF dominates bottom layer next to anode. The uniformity of lithium deposition is remarkably improved with the bilayer SEI, mitigating the consumption rate of active lithium and electrolytes. The cycle life of lithium metal batteries with bilayer SEI is three times as that with common anion‐derived SEI under practical conditions. A prototype lithium metal pouch cell of 430 Wh kg−1 undergoes 173 cycles. This work demonstrates the effect of a reasonable structure of SEI on reforming SEI uniformity. [ABSTRACT FROM AUTHOR]

Uncontrolled Zn dendrites and undesirable side reactions such as Zn self‐corrosion and hydrogen evolution reaction (HER) remain major challenges for the further development of aqueous Zn batteries (AZBs). In this study, macrolide antibiotics are proposed to be added to aqueous electrolyte, serving as Zn ionophores to modulate Zn2+ solvation structure, regulate Zn electrodeposition, and suppress undesirable parasitic reactions. Azithromycin (Azi), a representative macrolide antibiotic, is demonstrated to undergo bidentate coordination with Zn ions and remodel the solvation structure into [ZnAzi(H2O)4]2+. Meanwhile, the self‐corrosion and HER at the Zn anode side are significantly suppressed, evidenced quantitatively by the on‐line hydrogen production monitoring. Furthermore, the promotion of dense and uniform Zn electrodeposition by the ionophores is also confirmed. The repeated Zn plating/stripping test with 0.1 m Azi in electrolyte reaches a high cumulative capacity of 10 Ah cm−2 at a current density of 10 mA cm−2 and an area capacity of 10 mAh cm−2. Moreover, the corresponding Zn‐V2O5 pouch cell achieves stable operation for 100 cycles without bulging caused by gas evolution. Thus, the electrolyte engineering approach presents a practically viable strategy for the development of AZBs. [ABSTRACT FROM AUTHOR]

The lithium–sulfur battery is a promising electrochemical storage solution, especially for aviation and aeronautical applications, due to its high‐gravimetric energy density (specific energy) and the abundance of sulfur. In recent years, the number of reported prototype cells and their realized energy have increased. This underlines the progress of technology readiness of the lithium–sulfur system. However, the influence of the cathode porosity as well as the porosity of the carbon material on the performance of prototype cells is still not fully understood. Consequently, in this study, the porosity of solvent‐free processed cathodes is investigated, with varying carbon matrix composition, via mercury intrusion porosimetry and synchrotron tomography. Moreover, the swelling behavior of the S/C dry‐film cathodes is investigated and mitigated. These cathodes are then electrochemically evaluated at pouch cell level with ether‐based electrolytes with varying E/S ratios. The combination of the gained findings in pouch cells enables specific energies of 425 Wh kg−1 and 558 Wh L−1 at cell level. [ABSTRACT FROM AUTHOR]

Lithium‐sulfur (Li‐S) batteries have been regarded as promising next‐generation energy storage systems due to their high energy density and low cost, but their practical application is hindered by inferior long‐cycle stability caused by the severe shuttle effect of lithium polysulfides (LiPSs) and sluggish reaction kinetics. This study reports a La2O3‐MXene heterostructure embedded in carbon nanofiber (CNF) (denoted as La2O3‐MXene@CNF) as a sulfur (S) host to address the above issues. The unique features of this heterostructure endow the sulfur host with synergistic catalysis during the charging and discharging processes. The strong adsorption ability provided by the La2O3 domain can capture sufficient LiPSs for the subsequent catalytic conversion, and the insoluble thiosulfate intermediate produced by hydroxyl terminal groups on the surface of MXene greatly promotes the rapid conversion of LiPSs to Li2S via a "Wackenroder reaction." Therefore, the S cathode with La2O3‐MXene@CNF (La2O3‐MXene@CNF/S) exhibits excellent cycling stability with a low capacity fading rate of 0.031% over 1000 cycles and a high capacity of 857.9 mAh g−1 under extremely high sulfur loadings. Furthermore, a 5 Ah‐level pouch cell is successfully assembled for stable cycling, which delivers a high specific energy of 341.6 Wh kg−1 with a low electrolyte/sulfur ratio (E/S ratio). [ABSTRACT FROM AUTHOR]

Transitioning to more ambitious electrode formulations facilitates developing high-energy density cells, potentially fulfilling the demands of electric car manufacturers. In this context, the partial replacement of the prevailing anode active material in lithium-ion cells, graphite, with silicon-based materials enhances its capacity. Nevertheless, this requires adapting the rest of the components and harmonizing the electrode integration in the cell to enhance the performance of the resulting high-capacity anodes. Herein, starting from a replacement in the standard graphite anode recipe with 22% silicon suboxide at laboratory scale, the weight fraction of the electrochemically inactive materials was optimized to 2% carbon black/1% dispersant/3% binder combination before deriving an advantage from including single-wall carbon nanotubes in the formulation. In the second part, the recipe was upscaled to a semi-industrial electrode coating and cell assembly line. Then, 1 Ah lithium-ion pouch cells were filled and tested with different commercial electrolytes, aiming at studying the dependency of the Si-based electrodes on the additives included in the composition. Among all the electrolytes employed, the EL2 excelled in terms of capacity retention, obtaining a 48% increase in the number of cycles compared to the baseline electrolyte formulation above the threshold capacity retention value (80% state of health).

Abstract Monitoring and diagnosing the battery status in real‐time are of utmost importance for clarifying failure mechanism, improving battery performance, and ensuring safety, particularly under fast charging conditions. Recently, advanced operando techniques have been developed to observe changes in the microstructures of lithium deposits using laboratory‐scale cell designs, focusing on understanding the nature of Li metal electrodes. However, the macroscopic spatial inhomogeneity of lithium electroplating/stripping in the prototype pressurized pouch cells has not been measured in real‐time under practical conditions. Herein, a new noninvasive operando technique, spatial pressure mapping analysis, is introduced to macroscopically and quantitatively measure spatial pressure changes in a pressurized pouch cell during cycling. Moreover, dynamic spatial changes in the macroscopic morphology of the lithium metal electrode are theoretically visualized by combining operando pressure mapping data with mechanical analyses of cell components. Additionally, under fast charging conditions, the direct correlation between abrupt capacity fading and sudden increases in spatial pressure distribution inhomogeneity is demonstrated through comparative analysis of pouch cells under various external pressures, electrolyte species, and electrolyte weight to cell capacity (e/c) ratios. This operando technique provides insights for assessing the current battery status and understanding the complex origin of cell degradation behavior in pressurized pouch cells.

The absence of liquid components in all‐solid‐state batteries (ASSBs) based on sulfide solid electrolytes (SSEs) significantly impacts manufacturing processes and performance, particularly concerning mechanical properties and evolution. SSE films play vital roles in this context. This review provides a comprehensive analysis of SSE film design strategies, emphasizing their significance in the cell assembly and operation of practical ASSBs. Essential SSE film components are examined, including SSEs, binders, and scaffold or substrate materials, and key characteristics related to ASSB assembly and operation are addressed, such as conduction properties, electrochemical stability, and mechanical properties. Various SSE films fabricated using different binders and scaffold or substrate materials are explored through slurry‐casting or solvent‐free methods, and ASSBs employing SSE films with diverse form factors and components are presented, emphasizing their ability to operate under low‐pressure conditions. Additionally, the importance of establishing test protocols for assessing SSE film performance metrics is highlighted and strategies for enabling Li metal anodes are introduced. By deepening the understanding of the electrochemo‐mechanical phenomena and engineering processes in ASSBs, it is anticipated that the gap between lab‐scale research and practical goals can be bridged through design strategies that leverage the hybridization of various compositions and the immiscible nature of solid‐state materials. [ABSTRACT FROM AUTHOR]

Although there are various strategies for solid‐state polymer lithium batteries (SSPLBs) manufacturing, the most promising is the in situ polymerization process. The in situ polymerization process inherits good liquid electrolyte/electrode interfacial contact and is compatible with existing lithium‐ion batteries manufacturing processes, making it easy to achieve scale‐up production. However, most of the current studies on the in situ polymerization process are based on lab‐level coin cells, while practical pouch cells are much less studied. There is a huge difference between lab‐level coin SSPLBs and practical pouch SSPLBs. Here, as a complement to the existing reports and reviews, a systematic review of the challenges and design principles of in situ polymerization process for fabricating practical pouch SSPLBs is provided to enable a comprehensive understanding and strategic guidance for practical SSPLBs applications. This review thoroughly discusses recent advances regarding the fabrication of SSPLBs using in situ polymerization process and presents the existing challenges and future outlook for the fabrication of practical SSPLBs by in situ polymerization processes. Furthermore, the critical issues of electrode materials for manufacturing practical SSPLBs are highlighted during the in situ polymerization process, and an attempt is made to call more attention to the performance of the practical pouch SSPLBs. [ABSTRACT FROM AUTHOR]

Practical lithium–sulfur (Li−S) batteries are severely plagued by the instability of solid electrolyte interphase (SEI) formed in routine ether electrolytes. Herein, an electrolyte with 1,3,5‐trioxane (TO) and 1,2‐dimethoxyethane (DME) as co‐solvents is proposed to construct a high‐mechanical‐stability SEI by enriching organic components in Li−S batteries. The high‐mechanical‐stability SEI works compatibly in Li−S batteries. TO with high polymerization capability can preferentially decompose and form organic‐rich SEI, strengthening mechanical stability of SEI, which mitigates crack and regeneration of SEI and reduces the consumption rate of active Li, Li polysulfides, and electrolytes. Meanwhile, DME ensures high specific capacity of S cathodes. Accordingly, the lifespan of Li−S batteries increases from 75 cycles in routine ether electrolyte to 216 cycles in TO‐based electrolyte. Furthermore, a 417 Wh kg−1 Li−S pouch cell undergoes 20 cycles. This work provides an emerging electrolyte design for practical Li−S batteries. [ABSTRACT FROM AUTHOR]

Lithium–sulfur (Li–S) batteries are regarded as promising high‐energy‐density energy storage devices. However, the cycling stability of Li–S batteries is restricted by the parasitic reactions between Li metal anodes and soluble lithium polysulfides (LiPSs). Encapsulating LiPS electrolyte (EPSE) can efficiently suppress the parasitic reactions but inevitably sacrifices the cathode sulfur redox kinetics. To address the above dilemma, a redox comediation strategy for EPSE is proposed to realize high‐energy‐density and long‐cycling Li–S batteries. Concretely, dimethyl diselenide (DMDSe) is employed as an efficient redox comediator to facilitate the sulfur redox kinetics in Li–S batteries with EPSE. DMDSe enhances the liquid–liquid and liquid–solid conversion kinetics of LiPS in EPSE while maintains the ability to alleviate the anode parasitic reactions from LiPSs. Consequently, a Li–S pouch cell with a high energy density of 359 Wh kg−1 at cell level and stable 37 cycles is realized. This work provides an effective redox comediation strategy for EPSE to simultaneously achieve high energy density and long cycling stability in Li–S batteries and inspires rational integration of multi‐strategies for practical working batteries. [ABSTRACT FROM AUTHOR]

The silicon (Si) or silicon monoxide (SiOx)‐graphite (Gr)/nickel‐rich LiNixMnyCozO2 (NMC, x+y+z=1, with x≥80 %) cell chemistry is currently regarded as a promising candidate to further improve the energy density of rechargeable lithium‐ion batteries, but is confronted with safety and cycling stability issues. Here, the flame retardant ethoxy(pentafluoro)cyclotriphosphazene (PFPN) is studied as electrolyte additive in the SiOx‐Gr/NMC811 full cell system. We find that PFPN in combination with an increased lithium hexafluorophosphate (LiPF6) concentration renders carbonate‐based electrolytes non‐flammable based on a very low self‐extinguishing time of 3.1 s g−1 while the electrolyte maintains a high ionic conductivity of 8.4 mS cm−1 at 25 °C. Importantly, PFPN in combination with fluoroethylene carbonate (FEC) also stabilizes the solid‐electrolyte interphase of Si‐based anodes beyond the level achieved only with FEC. Furthermore, PFPN improves the wetting property of the electrolyte, rendering it a multifunctional additive. As a result, excellent capacity retention of 87 % after 200 cycles at 1 C was achieved for SiOx‐Gr/NMC811 pouch cells with a relatively high SiOx content of 20 %. Our work provides a promising avenue for developing safe and high‐performance electrolytes for lithium‐ion batteries with silicon‐based anodes. [ABSTRACT FROM AUTHOR]

Introducing sodium as anode to develop sodium metal batteries (SMBs) is a promising approach for improving the energy density of sodium‐ion batteries. However, fatal problems, such as uncontrollable sodium dendrite growth, unstable solid electrolyte interphase (SEI) in low‐cost carbonate‐based electrolytes, and serious safety issues, greatly impede the practical applications. Here, a multifunctionalized separator is rationally designed, by coating PP separator (<25 µm) with a solid‐state NASICON‐type fast ionic conductor layer (NZSP@PP) to replace the widely used thick glass fiber separator (>200 µm) and successfully solves all of the above problems, and for the first time creats high performance SMBs by using Na3V2(PO4)3 (NVP) cathodes in pouch cell. The Na||NVP full cells can stably cycle over 1200 times with capacity retention of 80% at a high rate of 10 C and deliver a specific capacity of 80 mAh g−1 even at high rate of 30 C, indicating extraordinary fast‐charging characters. The full SMBs can also stably cycle 200 times with a retention of 96.4% under high NVP loading of 10.7 mg cm−2. Most importantly, the SMB pouch cell can also deliver a long‐life cycles as well as high‐temperature battery performance, which guarantees the safety of SMBs in practical application. [ABSTRACT FROM AUTHOR]

Lithium-sulfur (Li-S) battery is considered as a promising energy storage system due to its ultrahigh theoretical energy density of 2,600 Wh·kg−1. Redox mediation strategies have been proposed to promote the sluggish sulfur redox kinetics. Nevertheless, the applicability of redox mediators in practical high-energy-density Li-S batteries has seldomly been manifested. In this work, 5,7,12,14-pentacenetetrone (PT) is proposed as an effective redox mediator to promote the sulfur redox kinetics under practical working conditions. A high initial specific discharge capacity of 993 mAh·g−1 is achieved at 0.1 C with high-sulfur-loading cathodes of 4.0 mgS·cm−2 and low electrolyte/sulfur (E/S) ratio of 5 µL·mgS−1. More importantly, practical Li-S pouch cells with the PT mediator realize an actual initial energy density of 344 Wh·kg−1 and cycle stably for 20 cycles wih a high capacity retention of 88%. This work proposes an effective redox mediator and further verifies the redox mediation strategy for practical high-energy-density Li-S batteries. [ABSTRACT FROM AUTHOR]

The ceramic composite separators coated with silica or alumina particles have been used in power batteries due to their better electrolyte wettability and better thermal stability compared with bare polymer separators. However, these oxide ceramics are Li+ ion insulators, which increase internal resistance and hinder the improvement of rate capability of batteries. Herein, we report a strategy to further improving the performance of lithium-ion batteries (LIBs) by using fast ionic conductor ceramic composite separator as an alternative to traditional ceramic coated separators. Lithium lanthanum titanate (LLTO), a fast ionic conductor with excellent room temperature bulk conductivity, are coated on the common polyethylene (PE) separators. Our results demonstrate that such a novel LLTO-coated separator possess excellent electrolyte wettability and thermal stability; and the assembled NCM523/graphite lithium-ion pouch cells with LLTO-coated separator show better rate capability and cyclic performance with 88.7% capacity retention after 1000 cycles at room temperature compared with the pouch cells with Al2O3-coated separators. The fast ionic conductor ceramic composite separators will be a potential competitor to the next-generation novel separators for high-performance Li-ion power batteries.

Currently, graphite (Gr) and potassium metal are two typical and widely used anodes for potassium‐ion batteries (PIBs). Unfortunately, the inevitable electrochemical prepotassiation of Gr anode and the unprocessable nature of K metal hinder the advancement of potassium‐ion pouch cells. There is an urgent need to develop alternative anodes for promoting the practical applications of PIBs. Herein, KC8 is proposed as a specialized anode for the research of PIBs. By taking a chemical prepotassiation strategy, a large‐area KC8 foil is successfully fabricated for the first time. Through molecularly tailoring K‐arene complex, the Gibb's free energy of the Gr prepotassiation reaction can be changed, thus enabling accurate preparation of pure‐phase KC8.The size‐controllable KC8 anode exhibits a high areal capacity of 1.49 mAh cm−2 comparable to the commercial Gr anode used in lithium‐ion batteries. Based on this, a stackable pouch cell delivers an unprecedented high capacity of 106 mAh and high energy density >100 Wh kg−1cathode+anode. This work highlights the prospect of scalable KC8 foil anodes to achieve practical PIBs. [ABSTRACT FROM AUTHOR]

Eutectic electrolytes are emerging to be explored to meet the high demand for aqueous zinc‐ion capacitors (AZICs) due to their high electrochemical stability and environmental‐friendly feature. Notably, a large‐scale requirement for a practical AZIC has been addressed to balance decent performance and increase package size. Thus, a "duet‐insurance" eutectic electrolyte (DIEE) is proposed by introducing successively heavy water (D2O) and dimethyl sulfoxide in an aqueous chaotropic Zn salt solution, which hindered the severe irreversibility of Zn anodes compared to that lacking this dual‐solvent protection. For example, the optimal DIEE delivered a high capacitance of 352.9 F g−1 at 0.5 A g−1 and excellent capacitance retention of ≈100% over 30,000 cycles at 2 A g−1 implementing in pouch cells and showing the ability to operate at a low temperature. Besides, experimental (e.g., nuclear magnetic resonance spectroscopy, Raman spectroscopy, electric double‐layer capacitance, etc.) and theoretical techniques (e.g., molecular dynamics simulation, density functional theory) illustrate the vital presence of contact ion pairs and aggregates ion species. Ultimately, this efficient DIEE system employing "duet‐insurance" protections provides a promising direction for designing novel eutectic electrolytes for AZICs chemistries. [ABSTRACT FROM AUTHOR]

Li-metal anode (LMA) is considered promising for overcoming the energy density limit of current Li-ion batteries. However, LMAs in large-scale cells are limited by uneven and excessive anode swelling, owing to the notorious buildup of a highly porous passivation ("dead" Li) layer. To demonstrate the impact of the pressure environment on the LMA swelling behavior and cycling stability, the distribution of the actual stack pressure was visualized in pouch cell platforms using pressure-sensitive films. If the stack pressure is not uniform, pouch cell failure occurs regardless of how high the applied pressure is. Conformal stack pressure assisted by the modified pressure setup with force redistributing pads enabled stable cycling even at a lower external pressure. By correlating with the thickness distribution of the "dead" Li layer over the LMA surfaces after cycling, it is suggested that a uniform stack pressure is crucial for mitigating anode swelling and the stable cycling of Li metal pouch cells. [ABSTRACT FROM AUTHOR]

Lithium‐organosulfur (Li‐OS) batteries, despite possessing high theoretical specific capacity, encounter a few practical challenges, including unsatisfactory lifespan and low active material utilization under realistic conditions. Here, diisoropyl xanthogen polysulfide (DIXPS) has been selected as a model organosulfur compound to investigate the practical feasibility of Li‐OS batteries under realistic conditions. A well‐designed freestanding carbon sponge decorated with Fe3N nanoparticles (C@Fe3N) is introduced into the Li‐OS cells as a scaffold for both Li and DIXPS. The lithiophilic property of the C@Fe3N host guides uniform lithium deposition at the anode, and the catalysis of the DIXPS conversion reaction promotes the kinetics at the cathode. Impressively, the synergistic effect of C@Fe3N leads to an extremely stable cycling performance over 1 000 cycles in a Li‐OS full cell under realistic conditions. [ABSTRACT FROM AUTHOR]

The stability of lithium metal anodes essentially dictates the lifespan of high‐energy‐density lithium metal batteries. Lithium nitrate (LiNO3) is widely recognized as an effective additive to stabilize lithium metal anodes by forming LiNxOy‐containing solid electrolyte interphase (SEI). However, its poor solubility in electrolytes, especially ester electrolytes, hinders its applications in lithium metal batteries. Herein, an organic nitrate, isosorbide nitrate (ISDN), is proposed to replace LiNO3. ISDN has a high solubility of 3.3 M in ester electrolytes due to the introduction of organic segments in the molecule. The decomposition of ISDN generates LiNxOy‐rich SEI, enabling uniform lithium deposition. The lifespan of lithium metal batteries with ISDN significantly increases from 80 to 155 cycles under demanding conditions. Furthermore, a lithium metal pouch cell of 439 Wh kg−1 delivers 50 cycles. This work opens a new avenue to develop additives by molecular modifications for practical lithium metal batteries. [ABSTRACT FROM AUTHOR]

Lithium metal battery has been considered as one of the potential candidates for next‐generation energy storage systems. However, the dendrite growth issue in Li anodes results in low practical energy density, short lifespan, and poor safety performance. The strategies in suppressing Li dendrite growth are mostly conducted in materials‐level coin cells, while their validity in device‐level pouch cells is still under debate. It is imperative to address dendrite issues in pouch cells to realize the practical application of Li metal batteries. This review presents a comprehensive overview of the failure mechanism and regulation strategies of Li metal anodes in practical pouch cells. First, the gaps between the scientific findings in materials‐level coin cells and device‐level pouch cells are underscored. Specific attention is paid to the mechanistic understanding and quantitative discussion on the failure mechanisms of pouch‐type Li metal batteries. Subsequently, recently proposed strategies are reviewed to suppress dendrite growth in pouch cells. The state‐of‐the‐art electrochemical performance of pouch cells, especially the cell‐level energy density and lifespan, is critically concerned. The review concludes with an attempt to summarize the scientific and engineering understandings of pouch‐type Li metal anodes and propose some novel insights for the practical applications of Li metal batteries. [ABSTRACT FROM AUTHOR]

Dissolution of lithium polysulfides (LiPSs) is essential for fast cathode kinetics, but detrimental for anode stability, especially under lean electrolyte conditions. In this work, the phase separation phenomenon between solvents with different polarities (tetramethyl sulfone [TMS] and dibutyl ether [DBE]) is utilized to enable the design of a dual‐phase electrolyte. High‐polarity, high‐density TMS–lithium bis(trifluoromethanesulfonyl)imide–ammonium trifluoroacetate as the cathode electrolyte strongly solvates LiPSs, which propel the sulfur redox reaction. Moreover, the composite of DBE and a polymeric ion conductor serves as the anode electrolyte. The addition of DBE in the anode side effectively prevents the crossover of corrosive species (LiPSs and ammonia trifluoroacetate), enabling a significant improvement in Li‐metal anode stability. The electrode‐specific dual‐phase electrolyte design provides electrochemical performance superior to conventional electrolytes. Without additional electrode engineering, pouch cells assemble with the dual‐phase electrolyte cycle under a lean electrolyte (4 µL mg−1) and low‐Li‐excess condition (N/P = 3) for 120 cycles. [ABSTRACT FROM AUTHOR]

High-voltage spinel LiNi0.5Mn1.5O4 (LNMO) is a promising candidate as a lithium-ion battery cathode material to fulfill the high-energy density demands of the electric vehicle industry. In this work, the design of the experiment’s methodology has been used to analyze the influence of the ratio of the different components in the electrode preparation feasibility of laboratory-scale coatings and their electrochemical response. Different outputs were defined to evaluate the formulations studied, and Derringer–Suich’s methodology was applied to obtain an equation that is usable to predict the desirability of the electrodes depending on the selected formulation. Afterward, Solver’s method was used to figure out the formulation that provides the highest desirability. This formulation was validated at a laboratory scale and upscaled to a semi-industrial coating line. High-voltage 1 Ah lithium-ion pouch cells were assembled with LNMO cathodes and graphite-based anodes and subjected to rate-capability tests and galvanostatic cycling. 1 C was determined as the highest C-rate usable with these cells, and 321 and 181 cycles above 80% SOH were obtained in galvanostatic cycling tests performed at 0.5 C and 1 C, respectively. Furthermore, it was observed that the LNMO cathode required an activation period to become fully electrochemically active, which was shorter when cycled at a lower C-rate.

Abstract The stability of lithium metal anodes essentially dictates the lifespan of high‐energy‐density lithium metal batteries. Lithium nitrate (LiNO3) is widely recognized as an effective additive to stabilize lithium metal anodes by forming LiNxOy‐containing solid electrolyte interphase (SEI). However, its poor solubility in electrolytes, especially ester electrolytes, hinders its applications in lithium metal batteries. Herein, an organic nitrate, isosorbide nitrate (ISDN), is proposed to replace LiNO3. ISDN has a high solubility of 3.3 M in ester electrolytes due to the introduction of organic segments in the molecule. The decomposition of ISDN generates LiNxOy‐rich SEI, enabling uniform lithium deposition. The lifespan of lithium metal batteries with ISDN significantly increases from 80 to 155 cycles under demanding conditions. Furthermore, a lithium metal pouch cell of 439 Wh kg−1 delivers 50 cycles. This work opens a new avenue to develop additives by molecular modifications for practical lithium metal batteries.

The rapid formation and accumulation of inactive lithium (Li) are principally responsible for the limited lifespan of high‐energy‐density Li metal batteries. The construction of composite Li metal anode with hosts emerges as a promising strategy to mitigate and accommodate inactive Li. However, the mechanism of inactive Li accumulation in composite Li metal anodes remains unknown, severely plaguing the stability of composite Li metal anodes. Herein, the two‐stage accumulation mechanism of inactive Li in composite Li metal anodes and its correlation with the stability of composite Li metal anodes are comprehensively unveiled in pouch cells by nondestructive 3D X‐ray microscopy. First, inactive Li accumulates in the interior of the host and results in a slowly increased polarization. Second, inactive Li overflows the inside of the host and induces a dramatically increased polarization chiefly responsible for the fast decay of the composite Li metal anodes. The current density and external pressure are identified as key factors to regulate the turning point between the two stages for practical composite Li metal anodes. This work provides original fundamentals for the recognition of inactive Li accumulation in composite Li metal anodes and the design of practical Li metal batteries. [ABSTRACT FROM AUTHOR]