Li Batteries Research Articles

Enabling superior cathode/sulfide electrolyte interfacial stability by Li3BO3 coating for all solid-state Li battery

Enabling superior cathode/sulfide electrolyte interfacial stability by Li3BO3 coating for all solid-state Li battery

Grain-Boundary-Rich Interphases for Rechargeable Batteries.

The formation of stable interphases on the electrodes is crucial for rechargeable lithium (Li) batteries. However, next-generation high-energy batteries face challenges in controlling interphase formation due to the high reactivity and structural changes of electrodes, leading to reduced stability and slow ion transport, which accelerate battery degradation. Here, we report an approach to address these issues by introducing multicomponent grain-boundary-rich interphase that boosts the rapid transport of ions and enhances passivation toward prolonged lifespan. This is guided by fundamental principles of solid-state ionics and geological crystallization differentiation theory, achieved through improved solvation chemistry. Demonstrations showcase how the introduction of the interphase substantially impacts the Li-ion transport across the interphase and the electrode-electrolyte compatibility in cost-effective electrolyte solutions optimized with multiple Li salts. The resulting interphases feature microstructures rich in inorganic grain boundaries with a diverse array of nanosized grains, presenting enhanced Li-ion transport. Comprehensive analyses revealed that this realizes remarkable electrochemical stability over extended cycling periods by inhibiting electrode corrosion, thus holding promise for high-capacity thin-Li-metal, Si-based anodes, and even Li-free anodes when paired with high-capacity oxide cathodes. This work opens new avenues to customize protective interphases on high-capacity electrodes, promoting the development of batteries with the highest energy density using cost-effective electrolytes.

Bismuth and Fluorine Dual-Doping of Lithium Argyrodite toward High-Performance All-Solid-State Lithium Metal Batteries.

The chlorine-rich lithium argyrodite is considered a promising superionic conductor electrolyte, but its practical application is limited due to poor air stability and instability toward lithium metal. In this work, BiF3 is proposed as a multi-functional dopant for electrolyte modification, and the effects on the ionic conductivity, air stability, critical current density, and electrolyte/Li metal interfacial stability are studied. The results show that the doped electrolyte Li5.54P0.98Bi0.02S4.5Cl1.44F0.06 (LPBiSClF0.06) still maintains a relatively high ionic conductivity of 5.37 mS cm-1. Additionally, the formation of BiS45- unit and LiBiS2 phase provides high air/moisture resistibility. Meanwhile, the critical current density of the Li/LPBiSClF0.06/Li cell is increased two-fold (2.1 mA cm-2). The in-situ formation of LiF and Li-Bi alloy at the lithium metal/electrolyte interface plays a key role in achieving high performance. As a result, the assembled LCO@LNO/LPBiSClF0.06/Li battery retains 78.4% of its capacity after 100 cycles at 0.2C.

Two-Dimensional ABS4 (A and B = Zr, Hf, and Ti) as Promising Anode for Li and Na-Ion Batteries.

Metal ion intercalation into van der Waals gaps of layered materials is vital for large-scale electrochemical energy storage. Transition-metal sulfides, ABS4 (where A and B represent Zr, Hf, and Ti as monolayers as anodes), are examined as lithium and sodium ion storage. Our study reveals that these monolayers offer exceptional performance for ion storage. The low diffusion barriers enable efficient lithium bonding and rapid separation while all ABS4 phases remain semiconducting before lithiation and transition to metallic states, ensuring excellent electrical conductivity. Notably, the monolayers demonstrate impressive ion capacities: 1639, 1202, and 1119 mAh/g for Li-ions, and 1093, 801, and 671 mAh/g for Na-ions in ZrTiS4, HfTiS4, and HfZrS4, respectively. Average voltages are 1.16 V, 0.9 V, and 0.94 V for Li-ions and 1.17 V, 1.02 V, and 0.94 V for Na-ions across these materials. Additionally, low migration energy barriers of 0.231 eV, 0.233 eV, and 0.238 eV for Li and 0.135 eV, 0.136 eV, and 0.147 eV for Na make ABS4 monolayers highly attractive for battery applications. These findings underscore the potential of monolayer ABS4 as a superior electrode material, combining high adsorption energy, low diffusion barriers, low voltage, high specific capacity, and outstanding electrical conductivity.

PVDF and PEO Catholytes in Solid‐State Cathodes Made by Conventional Slurry Casting

AbstractAll‐solid‐state Li batteries are desired for better safety and energy density than Li‐ion batteries. However, the lack of a penetrating liquid electrolyte requires a much different approach to the design of cathodes. The solid catholyte must enable good Li+ conduction, form good interfaces with active material particles, and have the strength to bind the cathode together during repeated volume changes. Catholyte formulation is often simply adapted from Li‐ion design principles, adding a Li salt to the PVDF binder. Here we show that such a PVDF binder at 10 wt % loading is a starved catholyte condition that compromises cell performance. By substituting a 70 : 30 blend of PVDF:PEO, performance is improved while maintaining nearly the same areal loading of LFP active material. Increasing the catholyte fraction to 16 % can also improve performance, but in this case the benefit of including PEO is lessened, with PVDF alone being an adequate catholyte. EIS analysis shows that PEO helps to form charge transfer interfaces at 10 % catholyte, but that its inclusion can degrade interfaces when there is ample catholyte at 16 %. It is also shown that catholyte agglomeration can impede bulk Li conduction, indicating that microstructural factors are of critical importance.

Resource-efficient electrodes with metallized woven-glass-grid current collectors for lithium-ion batteries.

A novel class of resource-efficient, woven-glass-grid current collectors (CCs) for Li-ion batteries is introduced. These CCs are based on ultra-light multifilament glass threads, woven to a grid and surrounded with a thin metal layer (equivalent to a 1 µm-thick metal foil) in a roll-to-roll physical vapor deposition process. This saves > 90% of the required Cu and Al metals and reduces the mass of the CCs by > 80%. At the same time, the gravimetric capacity of anodes with graphite and cathodes with LiCoO2 active material increases by 48% and 14%, respectively, while full cells are characterized by an increase of 26%. Thus, the specific energy can be improved by 25%. A complete anode and cathode fabrication process from preparing the CCs and electrodes to cells is described and demonstrated in coin cell format. Coin cells with woven-glass-grid CCs achieved 300 cycles with a capacity retention of 93%, a Coulombic efficiency of > 99.9%, and a higher rate capability until a C-rate of 3C. This technology opens up new possibilities for designing ultralight CCs with dedicated surface properties for Li and beyond Li batteries.

Rapid Thermal Shutdown of Deep-Eutectic-Polymer Electrolyte Enabling Overheating Self-Protection of Lithium Metal Batteries.

Safety concerns and uncontrollable dendrite growths have severely impeded the advancement of lithium-metal batteries. Herein, a safe deep-eutectic-polymer electrolyte with built-in thermal shutdown capability is proposed by utilizing hydrophobic association of methylcellulose within a novel deep-eutectic-solvent. Specifically, at elevated temperatures, methylcellulose chains aggregate to form dense polymer networks due to hydrophobic association and break the solvation structure equilibrium inside the deep-eutectic system through encapsulating Li+ in polymer matrix, leading to quick solidification of the electrolyte. The solidified electrolyte obstructs Li+ transports and terminates electrochemical processes, protecting LMBs from unstoppable exothermic chain reactions. The accelerating rate calorimeter tests of 1 Ah pouch cells demonstrate that the as-prepared electrolyte significantly improves the onset self-heating temperature from 73°C for conventional electrolytes to 172°Cand prolongs the thermal runaway waiting time more than 20 hours. More impressively, benefiting from its favorable electrochemical performance, this polymer electrolyte enables LiNi0.8Mn0.1Co0.1O2||Li batteries to retain 92% capacity over 200 cycles and LiFePO4||Li batteries to maintain 90% capacity after 500 cycles. This research paves a promising avenue for enhancing both the safety and electrochemical performance of high-energy-density LMBs.

Dendrite-Free Lithium Batteries Enabled by an Artificial High-Dielectric Biopolymer Interface Layer.

Lithium (Li) metal batteries face challenges, such as dendrite growth and electrolyte interface instability. Artificial interface layers alleviate these issues. Here, cellulose nanocrystal (CNC) nanomembranes, with excellent mechanical properties and high specific surface areas, combine with polyvinylidene-hexafluoropropylene (PVDF-HFP) porous membranes to form an artificial solid electrolyte interphase (SEI) layer. The porous structure of PVDF-HFP equalizes the electric field near metallic lithium surfaces. The high mechanical modulus of CNC (6.2 GPa) effectively inhibits dendrite growth, ensures the uniform flow of lithium ions to the lithium metal electrode, and inhibits the growth of lithium dendrites during cycling. The synergy of high polarity β-phase poly(vinylidene fluoride) (PVDF) and CNC provides over 1000 h of stability for Li//Li batteries. Moreover, Li//LiFePO4 (LFP) full cells with this artificial protective layer perform well at 5 C, showcasing the potential of this film in lithium metal batteries.

Solid-State Lithium Batteries with In Situ Polymerized Acrylate-Based Electrolytes Capable of Electrochemically Stable Operation at 100 °C.

Solid polymer electrolytes (SPEs) typically consist of salts with mobile anions that could cause instabilities and parasitic side reactions in solid-state lithium (Li) batteries. To address this challenge, single-Li-ion conducting (SLIC) SPEs, where anions of Li salts are covalently attached to the polymer backbone, have been utilized to reduce the number of mobile anions. This approach improves the cationic transference number but is accompanied by a loss of ionic conductivity. In this work, we investigate a synergetic approach of using both a polymerizable SLIC salt and a conventional Li salt in a polymer matrix by in situ polymerization of the poly(propylene glycol) acrylate (PPGA) monomer. The synthesized hybrid SPEs show a high ionic conductivity of up to ∼2 × 10-4 S cm-1 and a relatively high Li-ion transference number of ∼0.4. With a significantly reduced fraction of mobile anions in the combined salt SPE, in situ polymerized SPE cells with a LiFePO4 (LFP) cathode achieve a stable performance for over 100 cycles at temperatures as high as 100 °C, which is unattainable with conventional Li salts or electrolytes. Furthermore, solid-state nuclear magnetic resonance spectra provide additional insights into differences in Li nucleus environments and emphasize a reduction in activation energy for hybrid SPEs due to their more open structure. This study opens the path for the fabrication of high-performance solid polymer Li batteries capable of operating at high temperatures using commercial battery fabrication equipment, as in situ polymerized acrylate-based polymers provide drop-in compatibility with conventional battery production, ease of acrylate polymerization, and inexpensive, facile SPE chemistry. We expect that further tuning of the acrylate-based SPE composition may allow further increases in its conductivity without sacrificing its electrochemical stability or mechanical properties.

Enhanced Wavelet Transform Dynamic Attention Transformer Model for Recycled Lithium-Ion Battery Anomaly Detection

Rapid advancements in electric vehicle (EV) technology have highlighted the importance of lithium-ion (Li) batteries. These batteries are essential for safety and reliability. Battery data show non-stationarity and complex dynamics, presenting challenges for current monitoring and prediction methods. These methods often fail to manage the variability seen in real-world environments. To address these challenges, we propose a Transformer model with a wavelet transform dynamic attention mechanism (WADT). The dynamic attention mechanism uses wavelet transform. It focuses adaptively on the most informative parts of the battery data to enhance the anomaly detection accuracy. We also developed a deep learning model with an improved Transformer architecture. This architecture is tailored for the complex dynamics of battery data time series. The model accounts for temporal dependencies and adapts to non-stationary behavior. Experiments on public battery datasets show our approach’s effectiveness. Our model significantly outperforms existing technologies with an accuracy of 0.89 and an AUC score of 0.88. These results validate our method’s innovation and effectiveness.

Synergistic Dual Electrolyte System of LATP and In‐ Situ Solod‐State PDOL System and its Improvement on the Performance of NCM811 Batteries

Abstract1,3‐Dioxolane (DOL) can undergo in‐situ polymerization in batteries to form solid‐state organic electrolyte PDOL. When applied to NCM811||Li battery system, PDOL electrolyte helps optimize the contact and interface stability between electrolyte and electrodes. This study explores the effects of PDOL with PE separators coated with Li1.3Al0.3Ti1.7(PO4)3(LATP) on the performance of NCM811||Li batteries. 2,2,2‐trifluoroethyl phosphite (DETFPi), was mixed with DOL at a 1 : 35 mass ratio. Then, LiBF4 was used to initiate in‐situ polymerization and thereby obtained DETFPi‐PDOL electrolyte after 24 h at room temperature. The composite electrolyte exhibits enhanced ion conductivity (1.59×10−4 S cm−1), high lithium ion transference number (0.78), wide electrochemical stability window (4.53 V), and high critical current density (2.2 mA cm−2). Li||PDOL@LATP||Li battery shows extremely low overpotential (35 mV) after a constant current stable cycle of 500 h at 1.0 mA cm−2. After 500 cycles at 1 C, the remaining capacity is 153.9 mAh g−1 with a capacity retention of 82.1 % in NCM811||PDOL@LATP||Li batteries. This indicates that the LATP coating on the surface of the PE separator plays an important role in optimizing the performance of DETFPI‐PDOL electrolyte batteries. LATP and DETFPI‐PDOL are effective in improving the cycling stability, rate performance, and interface state of NCM811 batteries.

Recycled lithium battery nanomaterials as a sustainable nanofertilizer: Reduced peanut allergenicity and improved seed quality

The rapidly increasing amount of end-of-life lithium iron phosphate (LiFePO4) batteries has raised significant environmental concerns. This study offers a strategy for a paradigm shift by transforming this growing waste into a valuable resource by recycling discarded LiFePO4 batteries and safely integrating the materials into sustainable agriculture. We used five types of LiFePO4 (10, 50 mg kg−1) applied to soil planted with peanuts in a full-culture experiment. Our results show that addition of <50 mg kg−1 of recycled nano-LiFePO4 (rn-LiFePO4) has a multifaceted positive impact on peanut because of sustainable release of nutrients and nano-specific effects, not only enhancing photosynthesis and root growth but also increasing yield by 22 %–34 % while simultaneously elevating seed nutritional quality. Moreover, a remarkable reduction (up to 99.78 % at 10 mg kg−1 rn-LiFePO4) in the expression of allergen genes was evident following exposure to LiFePO4, which showed a significant negative correlation with Fe content in the seeds. The decreased peanut allergen gene expression was mediated by a downregulation of metabolites associated with protein digestion and absorption. Furthermore, rhizosphere soil immune system enhancement may indirectly enhance immune responses to peanut allergy. This study suggests the significant potential of nanoscale LiFePO4 recycled from Li battery, including enhancing crop yield quality and mitigating peanut allergy concerns while simultaneously addressing a growing waste stream of concern.

Remaining useful life prediction of high-capacity lithium-ion batteries based on incremental capacity analysis and Gaussian kernel function optimization

Remaining useful life (RUL) is a key indicator for assessing the health status of lithium (Li)-ion batteries, and realizing accurate and reliable RUL prediction is crucial for the proper operation of battery systems. As high-capacity Li batteries have more complex chemical properties, most of the current RUL prediction methods rely mainly on a priori knowledge to make judgments. As a result, prediction accuracy is not high. In this study, we developed a health indicator-capacity (HI-C) dual Gaussian process regression (GPR) model based on incremental capacity analysis (ICA) and optimized its kernel function to achieve accurate RUL prediction for 280 Ah high-capacity Li batteries. Validation against the United States National Aeronautics and Space Administration’s four battery test datasets showed that the use of the HI-C dual GPR model resulted in a mean absolute percentage error and root mean square error of less than 0.02 and 0.04, respectively, for the four battery-rated capacity predictions. Additionally, this model achieved an absolute error of less than five battery failure turns. Compared with a single model, the HI-C dual GPR model not only had high accuracy but also solved the problem that the HI was not measurable in the actual battery operation, which made it more suitable for RUL prediction of Li batteries.

Comparison of Construction Strategies of Solid Electrolyte Interface (SEI) in Li Battery and Mg Battery-A Review.

The solid electrolyte interface (SEI) plays a critical role in determining the performance, stability, and longevity of batteries. This review comprehensively compares the construction strategies of the SEI in Li and Mg batteries, focusing on the differences and similarities in their formation, composition, and functionality. The SEI in Li batteries is well-studied, with established strategies that leverage organic and inorganic components to enhance ion diffusion and mitigate side reactions. In contrast, the development of the SEI in Mg batteries is still in its initial stages, facing significant challenges such as severe passivation and slower ion kinetics due to the divalent nature of magnesium ions. This review highlights various approaches to engineering SEIs in both battery systems, including electrolyte optimization, additives, and surface modifications. Furthermore, it discusses the impact of these strategies on electrochemical performance, cycle life, and safety. The comparison provides insights into the underlying mechanisms, challenges, and future directions for SEI research.

Composite polymer electrolytes based on poly(ether-ester) and Li1.3Al0.3Ti1.7(PO4)3 enabling high-performance all-solid-state flexible lithium metal batteries

The quest for next-generation energy storage systems has led to the development of high-voltage all-solid-state lithium metal batteries (ASSLMBs), which promise unprecedented energy density and safety. However, the challenge lies in creating of a robust electrolyte that can meet high room temperature ionic conductivity, Li-ion transference number and a wide electrochemical stability window (ESW) while maintaining flexibility and compatibility with lithium metal anodes. Here, novel polyurethane-based composite polymer electrolytes (CPEs) have been successfully fabricated by the cross-linking reaction of poly(1,5-dioxepan-2-one) diols (poly(ether-ester) soft segment) and hexamethylene diisocyanate trimer (hard segment) (PDH) blending with inorganic NASICON-type ceramic fillers Li1.3Al0.3Ti1.7(PO4)3 (PDH@LATP). The resulting CPE exhibits an impressive ionic conductivity of 1.65 × 10−4 S cm−1 at room temperature and a Li-ion transference number of 0.63, which is attributed to the amorphous structure of PDH and the formation of an interconnected ionic pathway by the inorganic filler. The incorporation of LATP also improve the ESW of CPE to 5.3 V while maintaining good mechanical properties. Therefore, the assembled LiFePO4/PDH@LATP/Li batteries displayed low interfacial resistance, Li dendrite suppression, high specific capacity and excellent cyclic performance. The high-voltage LiNi0.5Co0.2Mn0.3O2/PDH@LATP/Li batteries also exhibits good cycling performance and durability. The design principles and materials presented herein provide a blueprint for the next wave of ASSLMBs.

Regulating interfacial reactions via quasi-solid polymer electrolyte to enable high-voltage lithium metal batteries

Sulfolane (SUL), known for its low cost, environmental friendliness, and high voltage tolerance, stands out as a promising polar solvent for lithium (Li) metal batteries with high energy density. However, its long-term stability with Li metal is compromised due to its inherently low reduction resistance. To address this issue, we introduce a novel electrolyte strategy, where the reactive SUL is encapsulated within a fluorinated polymer framework formed through in-situ thermal polymerization. The polymer network’s specific structure interacts with SUL, effectively mitigating its electrochemical degradation on the Li metal anode and the NCM811 cathode, thus enhancing electrode stability. This approach not only extends the Li+ plating/stripping reversibility for over 1,000 h at a current density of 0.3 mA cm−2, but also delivers outstanding performance in NCM811||Li batteries, achieving a capacity retention of 78.56 % after 1,000 cycles at 30 °C and 87.14 % after 100 cycles at 60 °C under a high cutoff voltage of 4.5 V.

Widening the Operational Temperature Range of Lithium Batteries Using Flame-Retardant Sulfone-Based Highly Concentrated Electrolytes

High-concentration Li salt/sulfone solutions have attracted attention as promising liquid electrolytes for Li batteries owing to their high oxidative stability, nonflammability, and high Li+ ion transference number (t Li+). Herein, we report the temperature-dependent electrolyte properties of a sulfone-based ternary mixture composed of LiN(SO2F)2, sulfolane, and dimethyl sulfone, which enables Li batteries to operate in a wide temperature range. At −20 °C, the rate capability of a Li/LiCoO2 cell with the sulfone-based electrolyte was comparable to that with a conventional carbonate-based electrolyte, even though the ionic conductivity of the electrolyte was significantly lower in the former case (0.11 versus 2.92 mS cm−1). This is because the former electrolyte has a higher t Li+ value, effectively suppressing the concentration overpotential during cell charging and discharging. Moreover, the vapor pressure was much lower for the sulfone-based electrolyte than for the carbonate-based one, and the Li/LiCoO2 cell with the former electrolyte was successfully operated at 60 °C. This study provides insights into the characteristics of high-concentration electrolytes that affect the temperature dependence of Li battery performance.

Improving thermal stability and electrochemical performance of polymer solid electrolyte membranes with a novel TiO2@PA-APP composite additive

Polymer solid electrolytes (PSEs) are still under the safety risk because of flammability and low mechanical strength. Here a TiO2 coated piperazine-modified ammonium polyphosphate (TiO2@PA-APP) is synthesized and incorporated into poly (ethylene oxide) (PEO)-based PSE membranes to meet the above challenges. The thermal stability and ionic conductivity of PSE membrane incorporated with TiO2@PA-APP have been improved. Micro-scale combustion calorimetry experiments indicate a dramatic 70 % decrease in heat release rate, from 919 W g−1 to 267 W g−1. The lithium symmetric cell demonstrates remarkable durability, operating normally for 500 h with minimal polarization potential across various current densities at 60 °C. The all solid-state LiFePO4//Li battery using the cathode-supported TiO2@PA-APP/PEO-PSE membrane can reach a high discharge specific capacity of 153 mAh g−1 at 0.1 C and demonstrates good cycle performance, achieving a capacity retention rate of 88 % after 200 cycles at 0.2 C, along with an average coulombic efficiency of 99.24 %. These findings underscore the effectiveness of the TiO2@PA-APP flame retardant in fabricating solid-state lithium-ion batteries that provide enhanced safety and exceptional electrochemical performance.

Engineering the solvent-anion interactions of LiTFSI-based dual-salt electrolytes to sustain high-performance NCM622 cathodes

Electrolytes play a vital role in determining the performances of lithium-ion batteries (LIBs), especially the high-voltage LiNi0.6Co0.2Mn0.2O2 (NCM622) cathode in LiTFSI-based electrolytes. Herein, we report a high-capacity and stable NCM622 cathode that can be realized in LiTFSI-based (named T) carbonate electrolytes by tuning the intermolecular interactions using the added LiDFOB (named D). In the 1 M dual-salt electrolyte, the cathode failure and Al corrosion are suppressed in the 4.5 V-NCM622||Li batteries, because a uniform interfacial layer and weaker Li+-solvent interactions are built to inhibit the parasitic reactions. As a result, the capacity retention reaches 94.68% after 200 cycles and the 10 C-rate capacity is about 160 mA h g-1 in the 1 M T + D dual-salt electrolyte. Unlike the commonly used electrolyte, the FEC additive increases the de-solvation barrier and disturbs the cycle stability in (T + D) dual-salt systems. Density functional theory (DFT) calculation and nuclear magnetic resonance (NMR) spectra reveal that the additive FEC changes the solvent-solvent and solvent-anion interactions in the presence of T + D, which weakens the electrolyte-cathode compatibility. This work indicates that regulating the solvation structure and interfacial chemistry from solvent-solvent/anion interactions is promising for designing high-performance LIBs by using dual‐salt electrolytes.

Regulating the Manganese Valence State Improves the Kinetic Properties of Manganese‐Based Cathodes

AbstractManganese (Mn)‐based lithium (Li)‐ion batteries with high energy density and low cost have recently attracted considerable attention. One drawback of Mn‐based batteries is the severe capacity attenuation caused by the Jahn‐Teller effect, which distorts the crystal structure and reduces the kinetics of Li‐ion insertion/extraction in the cathodes. In this study, the Mn valence state is regulated on the surface of Mn‐based oxide particles and oxygen vacancies are introduced to facilitate rapid Li‐ion transport and charge storage by adding succinonitrile (SN) to Mn‐based cathodes. Because of the reaction between SN and Mn‐based cathode particles, the contents of Mn3+ ions and oxygen vacancies increase, leading to an improvement in the Li‐ion kinetic properties of the cathodes as well as a reduction in the dissolution of Mn from the cathodes. By regulating the Mn valence state, Li‐ion and Li metal batteries with LiMn2O4 or Li‐rich Mn‐based layered oxide cathodes show significantly enhanced discharge capacity and improved cyclic performance. This study demonstrates that regulating the valence state of Mn ions is an effective strategy for enhancing the electrochemical performance of Mn‐based Li batteries and that adding SN to the cathodes is a cost‐effective method for mass production.