Application Of Lithium Metal Batteries Research Articles

Polycarbonate-based composite polymer electrolytes with Al2O3 enhanced by in situ polymerized electrolyte Interlayers for all-solid-state lithium-metal batteries

Lithium-metal batteries (LMBs) have attracted significant attention as promising energy storage devices due to their high energy density. However, the practical application of LMBs is hindered by issues such as dendrite growth and electrolyte decomposition, which lead to poor cycling stability. To address these challenges, this study focuses on investigating the performance of poly(ethylene carbonate) (PEC)-based composite polymer electrolytes (CPEs) with an in situ polymerized poly(vinyl ethylene carbonate) (PVEC)-based electrolyte interlayer. The electrolytes were optimized by incorporating lithium bis(fluorosulfonyl)imide (LiFSI) salt, lithium bis(oxalato)borate (LiBOB) and lithium nitrate (LiNO3) additives, as well as Al2O3 filler. The objective was to improve the compatibility and cycling stability of LMBs by enhancing the electrolyte/electrode interfacial properties. Remarkably, the Li||Li symmetric cell utilizing the optimized CPE exhibited outstanding stability, operating for 700 h without short-circuiting at 0.1 mA cm−2, indicating excellent interfacial compatibility. Additionally, the Li||LiFePO4(LFP) cells using the same electrolyte demonstrated impressive performance, delivering initial discharge capacity of 159.32 mAh g−1 at 0.1 C with retention and coulombic efficiency close to 100 % after 100 cycles at 60 °C. This paper highlights the effectiveness of utilizing polymer electrolyte interlayers and additives like LiNO3 in CPEs to enhance the interfacial compatibility and cycling stability of LMBs.

Self‐smoothing lithium metal anode based on screen‐printed Cu‐mesh current collector for long‐term safety of lithium metal batteries

AbstractLithium metal is an attractive anode candidate to enable high‐energy lithium battery systems. However, nonideal dendrite growth at the anode/separator interface hinders the safe application of lithium metal batteries (LMBs). Three‐dimensional (3D) current collectors (CCs) with high specific surface area could afford a crucial effect on suppressing dendrites, yet still subject to large thickness/weight and limited scalability for large‐area fabrication. Here, we show an industry‐compatible screen‐printing technique to prepare ultrathin (∼1.5 μm) and ultralight (∼0.54 mg cm−2) Cu mesh on commercial Cu foil to realize a long‐term safety of LMBs. In contrast to conventional laboratory level techniques, the screen‐printed Cu‐mesh CCs (∼8.3 mg cm−2), which are even lighter than the original Cu foil (∼8.84 mg cm−2), show a high compatibility for large‐area fabrication. Meanwhile, the periodic Cu mesh can be also used to regulate the homogeneous distribution of Li‐ion flux and thus, be in favor of realizing self‐smoothing anodes at even deep and fast plating/stripping of lithium. The resulting lithium anodes demonstrate a long‐term cyclic life of ∼840 h at 1 mA cm−2 with a high Coulombic efficiency of 97.5%. LMBs with Cu‐mesh CCs exhibit outstanding capacity retentions of ∼87% after 350 cycles at 1 C and ∼80% after 200 cycles at 5 C, suggesting a significant step of printable 3D CCs toward practical application of high‐energy LMBs.

Inorganic Composition Modulation of Solid Electrolyte Interphase for Fast Charging Lithium Metal Batteries.

The solid electrolyte interphase (SEI) with lithium fluoride (LiF) is critical to the performance of lithium metal batteries (LMBs) due to its high stability and mechanical properties. However, the low Li ion conductivity of LiF impedes the rapid diffusion of Li ions in the SEI, which leads to localized Li ion oversaturation dendritic deposition and hinders the practical applications of LMBs at high-current regions (>3 C). To address this issue, a fluorophosphated SEI rich with fast ion-diffusing inorganic grain boundaries (LiF/Li3P) is introduced. By utilizing a sol electrolyte that contains highly dispersed porous LiF nanoparticles modified with phosphorus-containing functional groups, a fluorophosphated SEI is constructed and the presence of electrochemically active Li within these fast ion-diffusing grain boundaries (GBs-Li) that are non-nucleated is demonstrated, ensuring the stability of the Li || NCM811 cell for over 1000 cycles at fast-charging rates of 5 C (11mA cm-2). Additionally, a practical, long cycling, and intrinsically safe LMB pouch cell with high energy density (400Wh kg-1) is fabricated. The work reveals how SEI components and structure design can enable fast-charging LMBs.

Lithiophilic 3D scaffold orienteering induced Li uniform deposition for highly stable lithium metal batteries

With the restrict of dendrites growth and endless volume expansion, the practical application of lithium metal batteries is stagnant. Constructing 3D scaffold is an effective strategy, which is not only inhibiting the dendrites growth by redistribute the local current density, but also accommodating large volume fluctuate during Li metal plating/striping. Whereas, the “top-growth” mode of lithium deposit on current collector limited the utilization of 3D structure. Hence, Cu foam scaffold modified with ZnO coating is prepare through magnetron sputtering. The lithiophilic ZnO coating can adjusting electrons and Li+ distribution on the anode surface simultaneously, which can orienteering induce Li deposit on the bottom surface firstly, achieving “bottom-up” growth mode. Furthermore, benefiting from the reversible Li plating-striping behavior, the half-cell with CF-ZnO scaffold endows a longer lifespan at various current density, the symmetrical cell can stable cycle for more than 1100 h with steadily voltage hysteresis of 12 mV (1 mA cm−2, 1 mA h cm−2). For the practical application measurement, the LiFePO4 full cell has a lifespan for more than 1000 cycles with capacity retention of 79.19 % at 2 A g−1.

In situ high‐quality LiF/Li3N inorganic and phenyl‐based organic solid electrolyte interphases for advanced lithium–oxygen batteries

AbstractLithium metal shows a great advantage as the most promising anode for its unparalleled theoretical specific capacity and extremely low electrochemical potential. However, uncontrolled lithium dendrite growth and severe side reactions of the reactive intermediates and organic electrolytes still limit the broad application of lithium metal batteries. Herein, we propose 4‐nitrobenzenesulfonyl fluoride (NBSF) as an electrolyte additive for forming a stable organic–inorganic hybrid solid electrolyte interphase (SEI) layer on the lithium surface. The abundance of lithium fluoride and lithium nitride can guarantee the SEI layer's toughness and high ionic conductivity, achieving dendrite‐free lithium deposition. Meanwhile, the phenyl group of NBSF significantly contributes to both the chemical stability of the SEI layer and the good adaptation to volume changes of the lithium anode. The lithium–oxygen batteries with NBSF exhibit prolonged cycle lives and excellent cycling stability. This simple approach is hoped to improve the development of the organic–inorganic SEI layer to stabilize the lithium anodes for lithium–oxygen batteries.

High-performance lithium metal anode enhanced by multifunctional film of PAN@AgNWs with antimicrobial activity

Lithium metal is expected to be the perfect anode material for the next generation of rechargeable batteries owing to its ultra-high theoretical specific capacity, low density and the lowest redox potential. However, the practical application of lithium metal batteries faces serious challenges, including uneven lithium deposition, negative electrode volume expansion, and short circuits brought by dendritic protrusions. Although the 3D structure of silver nanowires is effective in inhibiting lithium dendrite growth and lithium metal volume expansion, it still suffers from lithium inhomogeneity caused by uneven distribution of silver nanowires and complicated preparation. Therefore, PAN@AgNWs collector was prepared by a simple suction filtration method, and uniform dispersion of silver nanowires and uniform deposition of lithium were achieved. Lithium nucleation overpotential and lithium dendrite formation can be effectively reduced by PAN@AgNWs hosts due to the reduction of local current density by 3D collectors and the improved lithiophilicity of silver nanowires. With low voltage hysteresis, the symmetric battery constructed with its composite anode may cycle steadily for 4500 hours at 1 mA cm−2 and 1 mAh cm−2. At the same time, the Li-PAN@AgNWs||LFP full cell still possesses a reversible of 144.18 mAh g−1 after 500 cycles at 1C. Moreover, due to large specific surface area and high surface energy of 3D silver nanowires, it exhibits excellent antimicrobial properties, with an inactivation efficiency of 96.3% after contacting with E. coli for 2.5 h. This work shows the possibility of using PAN@AgNWs in a large scale for LMBs, and paves the way for development of high-performance antimicrobial materials.

Suppressing lithium dendrite via hybrid interface layers for high performance quasi-solid-state lithium metal batteries

The quasi-solid-state metal battery stands out as a promising candidate for the advancement of scalable, safe, and high-performance battery technologies. However, a major challenge remains in the form of short circuits arising from dendrite penetration, a consequence of uneven lithium deposition at the solid electrolyte/lithium anode interface. To address this issue, an in-situ constructed three-dimensional LiCl/Li-Al hybrid protective layer was implemented to inhibit the growth of dendrites. The enhanced interfacial dynamics were meticulously elucidated through a synergistic analysis of simulation and experimental results, highlighting the facilitation of Li+ flux distribution and uniform mass transfers introduced by the lithiophilic Li-Al alloy component. As a result, the modified Li anode enables stable Li stripping/plating cycling at a high current density of 1.0 mA·cm−2 and over 500 h at 0.2 mA·cm−2 for 0.2 mAh·cm−2 in the quasi-solid-state symmetric batteries. Additionally, the full cell with a LiFePO4 cathode maintains a high discharge capacity of 136.2 mAh/g after 400 cycles at 0.5C with a capacity retention of approximately 90 %. These findings demonstrate the application potential of Li anodes with a surface treatment for quasi-solid-state lithium metal battery applications.

Eliminating lithium dendrites via dependable ion regulation of charged nanochannels

Reviving lithium metal anode is of great significance to developing high-energy-density batteries after addressing the lithium dendrite. Constructing functional separator with charged nanochannel configuration has been proven to be an effective way to inhibit nucleation of lithium dendrites due to the achievement of a fast and selective lithium ion transport. While the ion regulation capability of existing functional separators cannot be maximized because their nanochannels are much larger than the electric double layer (EDL) regions that dominate ion transport. Considering the tiny EDL thickness (∼1 nm) formed in the electrolyte, the sulfonate-rich covalent organic framework (COF) is developed as functional separator to achieve a dependable ion regulation based on the nano-confined channel (∼1.55 nm) and surface negative charges. Consequently, a high Li+ transference number tLi+ (0.85) and sufficient ionic conductivity (0.53 mS cm−1) are obtained simultaneously, which effectively alleviates dendrite nucleation and growth of lithium metal anode for over 1000 h. Moreover, the principle for fast and selective lithium-ion transport is revealed from a new perspective of EDL region embedded in the nanochannel. Overall, this work demonstrates a strategy to eliminate lithium dendrites via ion regulation of charged nanochannels, which is anticipated to promote the practical application of lithium metal batteries.

Synergy of Weakly Solvated Electrolyte and LiF-Reinforced Interphase Enables Long-Term Operation of Li-Metal Batteries at Low Temperatures.

Hindered by the high diffusion energy barrier of Li+ in graphite anode layers, the low-temperature application of traditional Li-ion batteries is limited. Lithium metal without intercalation and with excellent specific capacity is expected to support battery operation at low temperatures. However, due to the low conductivity, high freezing point, and strong solvation energy of traditional carbonate electrolytes, the application of lithium-metal batteries at low temperatures remains challenged. In this paper, an all-ester-based ternary solvent electrolyte based on fluorinated carbonate and methyl acetate is developed to improve the cyclic efficiency of the Li-metal anode at subzero temperatures. Methyl acetate, with low viscosity and low freezing point, endows Li+ with efficient transfer in the bulk phase at low temperatures. Fluorinated cosolvent regulates the solvation structure, thereby facilitating Li+ desolvation while forming a LiF-rich solid electrolyte interphase. The electrolyte exhibits good compatibility with the Li-metal anode, as confirmed by the significantly reduced kinetic barrier of Li+ diffusion at the interface. The theoretical calculations suggest that anions occupy the dominant positions within the inner solvation sheath. The in situ/ex situ characterizations provide straightforward evidence of a dendrite-free Li-metal electrode during cycling. As a result, the symmetric Li||Li cell is able to cycle stably for thousands of hours at current densities of 0.5 mA cm-2 and 1 mAh cm-2. When paired with a LiFePO4 cathode, the battery at 0.2 C (1 C = 170 mA g-1) has a capacity retention of 95.4% after 200 cycles at -15 °C and 92.6% after 100 cycles at -20 °C, respectively.

Eutectogel Electrolyte Constructs Robust Interfaces for High-Voltage Safe Lithium Metal Battery.

Dramatic growth of lithium dendrite, structural deterioration of LiCoO2 (LCO) cathode at high voltages, and unstable electrode/electrolyte interfaces pose significant obstacles to the practical application of high-energy-density LCO||Li batteries. In this work, a novel eutectogel electrolyte is developed by confining the nonflammable eutectic electrolyte in a polymer matrix. The eutectogel electrolyte can construct a robust solid electrolyte interphase (SEI) with inorganic-rich LiF and Li3N, contributing to a uniform Li deposition. Besides, the severe interface side reactions between LCO cathode and electrolyte can be retarded with an in situ formed protective layer. Correspondingly, Li||Li symmetrical cells achieve highly reversible Li plating/stripping over 1000h. The LCO||Li full cell can maintain 72.5% capacity after 1500 cycles with a decay rate of only 0.018% per cycle at a high charging voltage of 4.45V. Moreover, the well-designed eutectogel electrolyte can even enable the stable operation of LCO at an extremely high cutoff voltage of 4.6V. This work introduces a promising avenue for the advancement of eutectogel electrolytes, the nonflammable nature and well-regulated interphase significantly push forward the future application of lithium metal batteries and high-voltage utilization of LCO cathode.

Thermodynamic stability and ionic conductivity in lithium–germanium binary system

Lithium–germanium binary compounds are promising anode materials for secondary lithium-ion batteries due to their high capacity, low operating voltage, and high electronic conductivity of lithiated Ge. For their successful application in batteries, it is essential to know the temperature stability of different Li–Ge phases and the variation of their ionic conductivity depending on the operating temperatures of the batteries. This work aims to comprehensively study the thermodynamic stability and ionic conductivity in Li–Ge binary compounds using a combination of first-principle computations and machine-learning interatomic potentials. We calculated convex hulls of the Li–Ge system at various temperatures and a temperature–composition phase diagram was obtained, delineating stability fields of each phase. Our calculations show that at temperatures higher than 590 K, LiGe undergoes a I41/a–P4/mmm transition, which leads to a change in the ionic conductivity. We show that all stable and metastable Li–Ge compounds have high ionic conductivity, but LiGe and Li7Ge12 have the lowest lithium diffusion. Trajectories of diffusion and Ge arrangements depend on lithium concentration. Based on advanced theoretical approaches, this study provides insights for the development of Li–Ge materials in lithium-ion and lithium-metal battery applications.

In-Situ Cross-linked F- and P-Containing Solid Polymer Electrolyte for Long-Cycling and High-Safety Lithium Metal Batteries with Various Cathode Materials.

The practical application of lithium metal batteries (LMBs) has been hindered by limited cycle-life and safety concerns. To solve these problems, we develop a novel fluorinated phosphate cross-linker for gel polymer electrolyte in high-voltage LMBs, achieving superior electrochemical performance and high safety simultaneously. The fluorinated phosphate cross-linked gel polymer electrolyte (FP-GPE) by in-situ polymerization method not only demonstrates high oxidation stability but also exhibits excellent compatibility with lithium metal anode. LMBs utilizing FP-GPE realize stable cycling even at a high cut-off voltage of 4.6 V (vs Li/Li+) with various high-voltage cathode materials. The LiNi0.6Co0.2Mn0.2O2|FP-GPE|Li battery exhibits an ultralong cycle-life of 1200 cycles with an impressive capacity retention of 80.1 %. Furthermore, the FP-GPE-based batteries display excellent electrochemical performance even at practical conditions, such as high cathode mass loading (20.84 mg cm-2), ultrathin Li (20 μm), and a wide temperature range of -25 to 80 °C. Moreover, the first reported solid-state 18650 cylindrical LMBs have been successfully fabricated and demonstrate exceptional safety under mechanical abuse. Additionally, the industry-level 18650 cylindrical LiMn2O4|FP-GPE|Li4Ti5O12 cells demonstrate a remarkable cycle-life of 1400 cycles. Therefore, the impressive electrochemical performance and high safety in practical batteries demonstrate a substantial potential of well-designed FP-GPE for large-scale industrial applications.

In‐Situ Cross‐linked F‐ and P‐Containing Solid Polymer Electrolyte for Long‐Cycling and High‐Safety Lithium Metal Batteries with Various Cathode Materials

AbstractThe practical application of lithium metal batteries (LMBs) has been hindered by limited cycle‐life and safety concerns. To solve these problems, we develop a novel fluorinated phosphate cross‐linker for gel polymer electrolyte in high‐voltage LMBs, achieving superior electrochemical performance and high safety simultaneously. The fluorinated phosphate cross‐linked gel polymer electrolyte (FP‐GPE) by in‐situ polymerization method not only demonstrates high oxidation stability but also exhibits excellent compatibility with lithium metal anode. LMBs utilizing FP‐GPE realize stable cycling even at a high cut‐off voltage of 4.6 V (vs Li/Li+) with various high‐voltage cathode materials. The LiNi0.6Co0.2Mn0.2O2|FP‐GPE|Li battery exhibits an ultralong cycle‐life of 1200 cycles with an impressive capacity retention of 80.1 %. Furthermore, the FP‐GPE‐based batteries display excellent electrochemical performance even at practical conditions, such as high cathode mass loading (20.84 mg cm−2), ultrathin Li (20 μm), and a wide temperature range of −25 to 80 °C. Moreover, the first reported solid‐state 18650 cylindrical LMBs have been successfully fabricated and demonstrate exceptional safety under mechanical abuse. Additionally, the industry‐level 18650 cylindrical LiMn2O4|FP‐GPE|Li4Ti5O12 cells demonstrate a remarkable cycle‐life of 1400 cycles. Therefore, the impressive electrochemical performance and high safety in practical batteries demonstrate a substantial potential of well‐designed FP‐GPE for large‐scale industrial applications.

Dynamic Interfacial Protection via Molecularly Tailored Copolymer for Durable Artificial Solid Electrolyte Interphase in Lithium Metal Batteries

AbstractThe serious dendrite formation and safety hazards associated with side reactions hinder the practical application of lithium metal batteries. A molecular customization strategy based on both physical and chemical properties is reported. A copolymer of acrylamide and hexafluorobutyl acrylate molecules is used as an artificial solid electrolyte interface(ASEI) for lithium metal to achieve dynamic interface protection during cycling. The amide group serves as the rigid unit, while the hexafluorobutyl group serves as the flexible unit, and imparts excellent mechanical properties to the copolymer. Synergistically abundant C─F bonds exhibit excellent water and oxygen resistance and have good electrolyte affinity. The ester and amide groups serve as amphiphilic sites for Li+ and PF6−, regulating the ion flux at the interface and achieving dendrite‐free lithium deposition. During cycling, the organic–inorganic composite SEI dynamically evolves to safeguard the lithium metal, preventing undue electrolyte consumption. The copolymer achieves stable cycling for 1500 and 950 h at 1 and 2 mA cm−2, respectively. It demonstrates excellent performance with LiNi0.8Co0.1Mn0.1O2 and LiFePO4 cathodes. This study introduces a new approach to designing polymers at the molecular level to optimize the physical properties/chemical activity of lithium metal interfaces.

Interlaced stacked hollow Cu2O dendrite for stable lithium metal anode

The stable operation of lithium metal batteries faces hindrances due to the persistent issue of uncontrolled lithium dendrite growth. In this study, we present a facile approach wherein 3D structured cuprous oxide (Cu2O) dendrites are constructed on flat copper foil through a straightforward process involving electrodeposition and subsequent high-temperature treatment. The thin lithium oxide (Li2O) layer stemming from lithiophilic Cu2O further establishes a conducive channel for the swift diffusion of lithium ions (Li+) at the solid-liquid interface. Notably, the staggered stacking of Cu2O dendrite results in a 3D structure with a significantly enlarged specific surface area, which not only mitigates current density but also promotes a uniform distribution of Li flow. The proposed Cu2O electrode yields superior performance, achieving a Coulombic efficiency of up to 98.2% and a sustained lithium deposition/stripping process lasting an impressive 880 h. In the full cells, employing Li/Cu2O dendrite electrode, an exceptional Coulombic efficiency (CE) of 99.9% is attained after 160 cycles at 1C, coupled with an admirable capacity retention rate of 84%. These findings underscore the promising potential of the Cu2O dendrite electrode for advancing the practical applications of lithium metal batteries.

Transesterification Induced Multifunctional Additives Enable High‐Performance Lithium Metal Batteries

AbstractThe electrolyte chemistry is crucially important for promoting the practical application of lithium metal batteries (LMBs). Here, we demonstrate for the first time that 1,3‐dimethylimidazolium dimethyl phosphate (DIDP) and trimethylsilyl trifluoroacetate (TMSF) can undergo in situ transesterification in carbonate electrolyte to generate dimethyl trimethylsilyl phosphate (DTMSP) and 1,3‐dimethylimidazolium trifluoroacetate (DITFA) as multifunctional additives for LMBs. H2O and HF can be removed by the Si−O group in DTMSP to improve the moisture resistance of electrolyte and the stability of cathode. Furthermore, the dissolution of lithium nitrate (LiNO3) in carbonate electrolyte can be promoted by the trifluoroacetate anion (TFA−) in DITFA, thereby optimizing the solvation structure and transport kinetics of Li+. More importantly, both DTMSP and DITFA tend to preferential redox decomposition due to the low lowest unoccupied molecular orbital (LUMO) and high highest occupied molecular orbital (HOMO). Consequently, a thin and robust layer rich in P/N/Si on the cathode and an inorganic‐rich layer (e.g. Li3N/Li3P) on the anode can be constructed and superior electrochemical performances are achieved. This artificial transesterification strategy to introduce favorable additives paves an efficient and ingenious route to high‐performance electrolyte for LMBs.

Transesterification Induced Multifunctional Additives Enable High-Performance Lithium Metal Batteries.

The electrolyte chemistry is crucially important for promoting the practical application of lithium metal batteries (LMBs). Here, we demonstrate for the first time that 1,3-dimethylimidazolium dimethyl phosphate (DIDP) and trimethylsilyl trifluoroacetate (TMSF) can undergo in situ transesterification in carbonate electrolyte to generate dimethyl trimethylsilyl phosphate (DTMSP) and 1,3-dimethylimidazolium trifluoroacetate (DITFA) as multifunctional additives for LMBs. H2O and HF can be removed by the Si-O group in DTMSP to improve the moisture resistance of electrolyte and the stability of cathode. Furthermore, the dissolution of lithium nitrate (LiNO3) in carbonate electrolyte can be promoted by the trifluoroacetate anion (TFA-) in DITFA, thereby optimizing the solvation structure and transport kinetics of Li+. More importantly, both DTMSP and DITFA tend to preferential redox decomposition due to the low lowest unoccupied molecular orbital (LUMO) and high highest occupied molecular orbital (HOMO). Consequently, a thin and robust layer rich in P/N/Si on the cathode and an inorganic-rich layer (e.g. Li3N/Li3P) on the anode can be constructed and superior electrochemical performances are achieved. This artificial transesterification strategy to introduce favorable additives paves an efficient and ingenious route to high-performance electrolyte for LMBs.

Anchoring Active Li Metal in Oriented Channel by In Situ Formed Nucleation Sites Enabling Durable Lithium-Metal Batteries.

Lithium metal is the ultimate anode material for pursuing the increased energy density of rechargeable batteries. However, fatal dendrites growth and huge volume change seriously hinder the practical application of lithium metal batteries (LMBs). In this work, a lithium host that preinstalled CoSe nanoparticles on vertical carbon vascular tissues (VCVT/CoSe) is designed and fabricated to resolve these issues, which provides sufficient Li plating space with a robust framework, enabling dendrite-free Li deposition. Their inherent N sites coupled with the in situ formed lithiophilic Co sites loaded at the interface of VCVT not only anchor the initial Li nucleation seeds but also accelerate the Li+ transport kinetics. Meanwhile, the Li2 Se originated from the CoSe conversion contributes to constructing a stable solid-electrolyte interphase with high ionic conductivity. This optimized Li/VCVT/CoSe composite anode exhibits a prominent long-term cycling stability over 3000h with a high areal capacity of 10 mAh cm-2 . When paired with a commercial nickel-rich LiNi0.83 Co0.12 Mn0.05 O2 cathode, the full-cell presents substantially enhanced cycling performance with 81.7% capacity retention after 300 cycles at 0.2 C. Thus, this work reveals the critical role of guiding Li deposition behavior to maintain homogeneous Li morphology and pave the way to stable LMBs.

Relocatable Hollow Multishelled Structure‐Based Membrane Enables Dendrite‐Free Lithium Deposition for Ultrastable Lithium Metal Batteries

AbstractLithium metal anode holds great promise due to its highest theoretical capacity and lowest redox potential. However, its practical application is hindered by lithium dendrite growth and exhaustive side reactions, which poses concerns to both cell performance and safety. Herein, a relocatable composite membrane is developed to simultaneously inhibit dendrite growth and stabilize solid electrolyte interphase (SEI) film. The compact packing of hollow multishelled structure (HoMS) provides percolated lithium ion channels and uniform ion flux, while the combined elastic polymer endows membrane structural flexibility to dynamically accommodate volume changes, which results in dendrite‐free lithium deposition inside HoMS and underneath the membrane and stable SEI film restricted to the outer surface of HoMS. Consequently, the membrane‐modified lithium metal half cell achieves an impressive Coulombic efficiency of 99.6% for over 600 cycles. Notably, full cell paired with LiFePO4 cathode stably runs for over 700 cycles, with a decay rate of only 0.045% per cycle, while the one paired with LiNi0.8Co0.1Mn0.1O2 cathode demonstrates a high capacity of 164.1 mAh g−1 at 1 C and a good capacity retention. This HoMS‐based composite membrane opens up new opportunities to realize the practical application of lithium metal batteries.

Solid Electrolyte Interphase Recombination on Graphene Nanoribbons for Lithium Anode.

The practical application of lithium metal batteries is hindered by the lithium dendrite issue, which is seriously affected by the composition and structure of the solid electrolyte interphase (SEI). Modifying the SEI can regulate lithium dendrite formation and growth. Here, we experimentally realize a Li protective layer of LiTFSI-ether electrolyte induced a natural SEI grafted on graphene nanoribbons (SEI@GNRs) via their in situ reactions. The experimental results and theoretical calculations uncover that the 3D structure of SEI@GNRs can reduce the local current density and Li+ flux. The natural SEI in SEI@GNRs, especially the rich inorganic species of LiF, Li3N, and Li2S, decreases the Li+ nucleation overpotential, makes Li+ ion deposition and nucleation uniform, and isolates electron transport. Their synergetic effect suppresses Li dendrite formation and growth, increasing the electrochemical performance of lithium metal batteries. The design strategy is beneficial for the development of lithium metal batteries.