Lithium Metal Anode Research Articles

Uniform Poly(vinyl ethylene carbonate) based metal-organic framework separator for smooth lithium-ion electrodeposition

Nanoporous feature in Metal-Organic Frameworks (MOFs) could tune Li+-solvated species and provide high potential for stabilizing lithium metal anodes. However, the inevitable voids within MOF crystallites accommodating free liquid electrolyte, which re-solvates Li+-solvated compounds and vanishes nanopores' advantage for controlling Li+-solvates. Herein, we report an in-situ carbonate photopolymerization reaction within MOF channel that constitutes a uniform nanoporous separator (PVEC-MOF) for smoothing Li+ electrodeposition. PVEC-MOF membrane exhibits accelerating lithium-ion conduction and superior electrochemical performance according to the interconnected ionic nano-channels, whose overpotential maintains at about 0.01 V after 600 cycles in Li-symmetric cell without forming lithium dendrite. Furthermore, employing PVEC-MOF separator in high-voltage cathode material (LiNi0.6Co0.2Mn0.2O2) based Li-metal batteries could effectively enhance electrochemical property and prolong cycling lifespan. This work provides a novel strategy to convert traditional MOF family into uniform nanoporous lithium-ion battery separator, which promotes Li+ smooth electrodeposition and inhibits lithium dendrites in high-energy-density lithium-metal batteries.

Bi-Functional Materials for Sulfur Cathode and Lithium Metal Anode of Lithium-Sulfur Batteries: Status and Challenges.

Over the past decade, the most fundamental challenges faced by the development of lithium-sulfur batteries (LSBs) and their effective solutions have been extensively studied. To further transfer LSBs from the research phase into the industrial phase, strategies to improve the performance of LSBs under practical conditions are comprehensively investigated. These strategies can simultaneously optimize the sulfur cathode and Li-metal anode to account for their interactions under practical conditions, without involving complex preparation or costly processes. Therefore, "two-in-one" strategies, which meet the above requirements because they can simultaneously improve the performance of both electrodes, are widely investigated. However, their development faces several challenges, such as confused design ideas for bi-functional sites and simplex evaluation methods (i. e. evaluating strategies based on their bi-functionality only). To date, as few reviews have focused on these challenges, the modification direction of these strategies is indistinct, hindering further developments in the field. In this review, the advances achieved in "two-in-one" strategies and categorizing them based on their design ideas are summarized. These strategies are then comprehensively evaluated in terms of bi-functionality, large-scale preparation, impact on energy density, and economy. Finally, the challenges still faced by these strategies and some research prospects are discussed.

Accelerating Lithium Deposition Kinetics Via Lithiophilic Ag‐Decorated Graphitic Carbon Nitride Spheres for Stable Lithium Metal Anode

This study presents a novel Li metal host material with a unique hollow nano‐spherical structure that incorporates Ag nano‐seeds into a graphitic carbon nitride (g‐C3N4) shell layer, referred to as g‐C3N4@Ag hollow spheres. The g‐C3N4@Ag spheres provide a managed internal site for Li metal encapsulation and promote stable Li plating. The g‐C3N4 spheres are uniformly coated using polydopamine, which has an adhesive nature, to enhance lithium plating/stripping stability. The strategic presence of Ag nano‐seeds eliminates the nucleation barrier, properly directing Li growth within the hollow spheres. This design facilitates highly reversible and consistent lithium deposition, offering a promising direction for the production of high‐performance lithium metal anodes. These well‐designed g‐C3N4@Ag hollow spheres ensure stable Li plating/stripping kinetics over more than 500 cycles with a high coulombic efficiency of over 97%. Furthermore, a full cell made using LiNi0.90Co0.07Mn0.03O2 and Li‐g‐C3N4@Ag host electrodes demonstrated highly competitive performance over 200 cycles, providing a guide for the implementation of this technology in advanced lithium metal batteries.

Boosting Li-Ion Conductivity of Fluoride Solid Electrolyte by Low-Temperature Molten Salt Ablation and Particle Boundary Doping.

Halide solid electrolytes (SEs) are attracting great attention, owing to their high ionic conductivity and excellent high-voltage compatibility. However, severe moisture sensitivity, poor thermal stability, and instability at the lithium metal anode interface with chloride and bromide SEs retard their applications in solid-state lithium metal batteries. Fluoride SEs are expected to solve these problems, but they are now plagued by inadequate room-temperature (RT) ionic conductivity. Herein, a low-temperature molten salt (LiCl+1.33AlCl3) ablation method is proposed to enhance the ionic conductivity of monoclinic Li3GaF6 by particle boundary doping. The RT ionic conductivity of Li3GaF6 is correspondingly increased by 2 orders of magnitude, and the conductivity reaches 10-4 S cm-1 at 60 °C. The improved ionic conductivity benefits from the enhancement of interfacial ion transport, with the formation of more conductive chlorine-doped Li3GaF6-xClx and in situ binder LiAlCl4 to cement surrounding nanoparticles. The as-synthesized Li3GaF6 demonstrates outstanding humidity tolerance without conductivity degradation after exposure to a relative humidity of up to 35%. It also exhibits the widest electrochemical stability window experimentally (close to 6 V) compared with other state-of-the-art SEs. The solid-state Li/Li3GaF6/LiFePO4 cell with a stable Li+-conductive polymer interface is successfully driven for at least 200 cycles at 0.5C. Our study provides a solution to various chemical and electrochemical stability issues encountered by the halide SE family.

2D Microporous Polymers/Reduced Graphene Oxide with Built-In Lithiophilic Sites for Uniform Lithium Deposition in Lithium Metal Anode.

Lithium (Li) metal is an attractive anode material for use in high-energy lithium-sulfur and lithium-air batteries. However, its practical application is severely impeded by excessive dendrite growth, huge volume changes, and severe side reactions. Herein, a novel Li metal anode composed of lithiophilic two dimensional (2D) conjugated microporous polymer (Li-CMP) and reduced graphene oxide (rGO) sandwiches (Li-CMP@rGO) for Li metal batteries (LiMBs) is reported. In the Li-CMP@rGO anode, the conductive rGO facilitates the charge transfer while the functionalized-CMP provides Li nucleation sites within the micropores, thereby preventing dendrite growth. As a result, the Li-CMP@rGO anode can be cycled smoothly at 6mA cm-2 of current density with a platting capacity of 2 mAh cm-2 for 1000h. A Coulombic efficiency of 98.4% is achieved over 350 cycles with a low overpotential of 28mV. In a full cell with LiFePO4 cathode, the Li-CMP@rGO anode also exhibited good cycling stability compared to CMP@rGO and CMP/Super-P. As expected, the simulation results reveal that Li-CMP@rGO has a strong affinity for Li ions compared to CMP@rGO. The strategies adopted in this work can open new avenues for designing hybrid porous host materials for developing safe and stable Li metal anodes.

Formulating Electrolytes for 4.6 V Anode-Free Lithium Metal Batteries

High-voltage initial anode-free lithium metal batteries (AFLMBs) promise the maximized energy densities of rechargeable lithium batteries. However, the reversibility of the high-voltage cathode and lithium metal anode is unsatisfactory in sustaining their long lifespan. In this research, a concentrated electrolyte comprising dual salts of LiTFSI and LiDFOB dissolved in mixing solvents of dimethyl carbonate (DMC) and fluoroethylene carbonate (FEC) with a LiNO3 additive was formulated to address this challenge. FEC and LiNO3 regulate the anion-rich solvation structure and help form a LiF, Li3N-rich solid electrolyte interphase (SEI) with a high lithium plating/stripping Coulombic efficiency of 98.3%. LiDFOB preferentially decomposes to effectively suppress the side reaction at the high-voltage operation of the Li-rich Li1.2Mn0.54Ni0.13Co0.13O2 cathode. Moreover, the large irreversible capacity during the initial charge/discharge cycle of the cathode provides supplementary lithium sources for cycle life extension. Owing to these merits, the as-fabricated AFLMBs can operate stably for 80 cycles even at an ultrahigh voltage of 4.6 V. This study sheds new insights on the formulation of advanced electrolytes for highly reversible high-voltage cathodes and lithium metal anodes and could facilitate the practical application of AFLMBs.

In‐Situ Constructing a Mixed‐Conductive Interfacial Protective Layer for Ultra‐Stable Lithium Metal Anodes

Lithium metal batteries are the most promising next‐generation energy storage technologies due to their high energy density. However, their practical application is impeded by serious interfacial side reactions and uncontrolled dendrite growth of lithium metal anode. Herein, copper 2,4,5‐trifluorophenylacetate is designed and explored to stabilize lithium metal anode by in‐situ constructing a dense and mixed‐conductive interfacial protective layer. The formed passivated layer not only significantly inhibits interfacial side reactions by avoiding direct contact between lithium metal anode and electrolyte but also effectively suppresses lithium dendrite growth due to the unique inorganic‐rich compositions and mixed‐conductive properties. As a result, the copper 2,4,5‐trifluorophenylacetate‐treated lithium metal anodes show greatly improved cycle stability under both high current density and high areal deposition capacity. Notably, the assembled liquid symmetrical cells with copper 2,4,5‐trifluorophenylacetate‐treated lithium metal anodes can stably work for more than 3000, 5000, and 4800 h at 1.0 mA cm−2–1.0 mAh cm−2, 2.0 mA cm−2–5.0 mAh cm−2, and 10 mA cm−2–5.0 mAh cm−2, respectively. Furthermore, the assembled liquid full cell with a high LiFePO4 loading (~16.9 mg cm−2) shows a significantly enhanced cycle life of 250 cycles with stable Coulombic efficiencies (>99.1%). Moreover, the assembled all‐solid‐state lithium metal battery with a high LiNi0.6Co0.2Mn0.2O2 loading (~5.0 mg cm−2) also exhibits improved cycle stability. These findings underline that the copper 2,4,5‐trifluorophenylacetate‐treated lithium metal anodes show great promise for high‐performance lithium metal batteries.

Demonstration of MAX phases as triple functional artificial solid electrolyte interphase for ultralong life lithium metal anodes

Solid electrolyte interphase (SEI) has significant role in controlling lithium (Li) dendrites. However, lack of chemical stability, mechanical strength and self-perfection for conventional SEI cannot persistently suppress Li dendrites, leading to inferior cycling life. Herein, MAX phases (Ti2SnC and Ti2SC) as triple functional artificial SEI (ASEI) with high modulus, chemical stability and self-smoothing ability are introduced on Li foils (Ti2SnC@Li and Ti2SC@Li) for ultralong life Li metal anodes (LMAs). The high mechanical strength with lithiophilicity of the MAX can induce uniform Li deposition and suppress dendrite growth, while the excellent chemical stability and self-smoothing ability of the MAX guarantee the consistency of the ASEI, achieving ultralong life of the LMAs. As a result, the Ti2SnC@Li||Li@Ti2SnC half-cells demonstrate ultralong cycling performance of 5000 h at 5 mAh cm−2 and 5 mA cm−2. The Ti2SnC@Li||LiFePO4(LFP) full-cells demonstrate ultralong stability up to 3000 cycles at 5C. At harsh conditions including 24.3 mg cm−2 of LFP, 6.0 g (Ah)−1 of electrolyte and 2.6 of negative/positive ratio, the Ti2SnC@Li||LFP full-cells maintain 2.9 mAh cm−2 after 130 cycles at 0.3C. This work demonstrates the MAX phases with high modulus, chemical stability and self-smoothing ability as triple functional ASEI for metal anode protection.

Long‐lifespan 522 Wh kg‐1 Lithium Metal Pouch Cell Enabled by Compound Additives Engineering

Matching high‐voltage cathodes with lithium metal anodes represents the most viable technological approach for developing secondary batteries with ultra‐high energy density exceeding 500 Wh kg‐1. Nevertheless, the instability of electrolyte/electrode interface film and commercial electrolytes with cut‐off voltage above 4.3 V is still a major concern. Herein, we present that excellent cycling stability with an ultra‐high cut‐off voltage of up to 5.0 V can be obtained by using three‐component additives containing fluoroethylene carbonate (FEC), hexadecyl trimethylammonium chloride (CTAC), and tri(pentafluorophenyl)borane (TPFPB). Excellent ionic conductivity, robust interfacial films on both electrodes, and long‐lasting uniform Li+ regulation ability can be obtained in the modifying electrolyte. Consequently, using a high plating/stripping capacity of 3 mAh cm‐2 under the current density of 1 mA cm‐2, lithium symmetric cells demonstrate stable cycling performance exceeding 800 hours. Meanwhile, the 7.3 Ah‐class Li[NixCoyMn1‐x‐y]O2 (x=0.83, NCM83)| Li pouch cells are assembled, which show a high energy density of 522 Wh kg‐1 and present excellent stability over 178 cycles with a high initial coulombic efficiency (CE) of 98.0%.

Long-Lifespan 522 Wh kg-1 Lithium Metal Pouch Cell Enabled by Compound Additives Engineering.

Matching high-voltage cathodes with lithium metal anodes represents the most viable technological approach for developing secondary batteries with ultra-high energy density exceeding 500 Wh kg-1. Nevertheless, the instability of electrolyte/electrode interface film and commercial electrolytes with cut-off voltage above 4.3 V is still a major concern. Herein, we present that excellent cycling stability with an ultra-high cut-off voltage of up to 5.0 V can be obtained by using three-component additives containing fluoroethylene carbonate (FEC), hexadecyl trimethylammonium chloride (CTAC), and tri(pentafluorophenyl)borane (TPFPB). Excellent ionic conductivity, robust interfacial films on both electrodes, and long-lasting uniform Li+ regulation ability can be obtained in the modifying electrolyte. Consequently, using a high plating/stripping capacity of 3 mAh cm-2 under the current density of 1 mA cm-2, lithium symmetric cells demonstrate stable cycling performance exceeding 800 hours. Meanwhile, the 7.3 Ah-class Li[NixCoyMn1-x-y]O2 (x=0.83, NCM83)|Li pouch cells are assembled, which show a high energy density of 522 Wh kg-1 and present excellent stability over 178 cycles with a high initial coulombic efficiency (CE) of 98.0 %.

Cyclosulfate additive inhibits Li dendrite disorder growth to achieve stable cycles of Li metal battery

ABSTRACT The high reactivity of lithium metal leads to the uncontrolled growth of lithium dendrites during the charging and discharging process of lithium metal batteries, which results in the poor cycle performance of batteries. In this paper, we innovatively utilized 1, 3-propanediol cyclic sulfate (PCS) as an additive to successfully construct a smooth and dense SEI layer containing sulfur element on the lithium metal anode surface. Under the action of PCS, the cells show excellent performance. After 200 cycles, cells with baseline electrolyte (BE) + 1 wt.% PCS still has a high capacity of of 148mAh g−1 and 81.38% capacity retention compared with cells with BE. In-situ optical microscopy is pioneeringly applied to showcase the generation and growth of lithium dendrites which showed that PCS participated in the formation of the SEI layer, indicating that this optimized SEI layer has better conductivity of Li+ and chemical stability, thus inhibiting malignant lithium deposition and electrolyte decomposition above the lithium metal anode.

SEI Formation and Lithium-Ion Electrodeposition Dynamics in Lithium Metal Batteries via First-Principles Kinetic Monte Carlo Modeling.

The stabilization and enhanced performance of lithium metal batteries (LMBs) depend on the formation and evolution of the Solid Electrolyte Interphase (SEI) layer as a critical component for regulating the Li metal electrodeposition processes. This study employs a first-principles kinetic Monte Carlo (kMC) model to simulate the SEI formation and Li+ electrodeposition processes on a lithium metal anode, integrating both the electrochemical electrolyte reduction reactions and the diffusion events giving place to the SEI aggregation processes during battery charge and discharge processes. The model replicates the competitive interactions between organic and inorganic SEI components, emphasizing the influence of the cycling regime. Results indicate that grain boundaries within the SEI facilitate faster lithium-ion transport compared to crystalline regions, crucial for improving the performance and stability of LMBs. The findings underscore the importance of dynamic SEI modeling for further development of next-generation high-energy-density batteries.

Cationic Covalent Organic Framework-Modified Polypropylene Separator for High-Performance Lithium Metal Batteries.

As an important component of lithium batteries, the wettability and thermal stability of the separator play a significant role in cell performance. Despite the availability of numerous commercial separators, issues such as low ion selectivity and poor thermal stability continue to limit the efficiency and reliability of the batteries. Herein, two cationic covalent organic frameworks (Br-COF and TFSI-COF) with abundant imidazole cationic groups were designed to modify commercial polypropylene (PP) separators. The strong lithium-ion affinity of the cationic COF enables the effective dissociation of lithium salt ion clusters, simplifying the solvent structure of lithium ions to promote lithium ions transport. Additionally, solvent anions can be anchored to the cationic COF by electrostatic interactions, reducing side reactions on the lithium metal anode surface to form a favorable SEI layer, which can effectively inhibit the growth of lithium dendrites. The rapid dissociation of anions in lithium salts with some organic solvents and cationic COFs was revealed by a molecular dynamics simulation. A LiF-rich SEI layer on the lithium metal anode surface was formed, which can speed up Li+ transport at interfaces, leading to consistent lithium deposition and outstanding battery performance. The ordered porous structure of the cationic COF provides interconnected and continuous channels, improving the wettability between the liquid electrolyte and separators, which is conducive to ion transport. When paired with a LiFePO4 cathode and electrolyte (1.0 M LiTFSI in DEC: EC: DMC = 1:1:1), the LiFePO4/TFSI-COF@PP/Li cell demonstrates a prominent cycling capacity of 148.0 mAh g-1 at 0.5 C with a Coulombic efficiency of 98.0% in the first cycle, and the capacity retention is 82.0% after 100 cycles, showing good cycling stability. Thus, this investigation provides inspiration for the expansion of cationic COF-modified separators for next-generation lithium metal batteries.

Boosting Fast Charging of Lithium-Metal Batteries via Weak Interactions Between Non-Solvating Solvents and Anions in High-Safety Eutectic Electrolytes.

Proper design of the solvation structure is crucial for the development of lithium metal batteries (LMBs). In this paper, the use of 1,2-Dimethoxyethane (DME) as a non-solvating cosolvent in amide-based eutectic electrolytes is proposed to address challenges related to high viscosity, high polarization, and low conductivity, thus enhancing the compatibility with lithium metal anodes. Through physical characterization combined with simulation calculations the existence of a weak interaction between DME and anions is confirmed, which promotes the dissociation of lithium salts and increases the Li+ transference number and diffusion coefficient, thus improving the fast charging performance of eutectic electrolytes. In addition, stable SEI layer enriched with inorganic components is formed during the cycling process, resulting in uniform and dense lithium deposition. The fast charging performance of the cell can be effectively improved by utilizing the interaction between anions and solvents. The LiFePO4 (LFP)||Li cell has a capacity retention of 97% after 1200 cycles at 5 C and also performs well at high temperature of 50°C. Overall, the use of a non-solvating cosolvent in eutectic electrolytes presents a promising and innovative approach for enhancing electrolyte performance in LMBs.

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.

Tailored Engineering on the Interface Between Lithium Metal Anode and Solid‐State Electrolytes

The replacement of non‐aqueous organic electrolytes with solid‐state electrolytes (SSEs) in solid‐state lithium metal batteries (SLMBs) is considered a promising strategy to address the constraints of lithium‐ion batteries, especially in terms of energy density and reliability. Nevertheless, few SLMBs can deliver the required cycling performance and long‐term stability for practical use, primarily due to suboptimal interface properties. Given the diverse solidification pathways leading to different interface characteristics, it is crucial to pinpoint the source of interface deterioration and develop appropriate remedies. This review focuses on Li|SSE interface issues between lithium metal anode and SSE, discussing recent advancements in the understanding of (electro)chemistry, the impact of defects, and interface evolutions that vary among different SSE species. The state‐of‐the‐art strategies concerning modified SEI, artificial interlayer, surface architecture, and composite structure are summarized and delved into the internal relationships between interface characteristics and performance enhancements. The current challenges and opportunities in characterizing and modifying the Li|SSE interface are suggested as potential directions for achieving practical SLMBs.

An artificial layer enables in situ generation of a homogeneous inorganic/organic composite solid electrolyte interphase for stable lithium metal batteries.

Lithium (Li) metal anodes are considered one of the most promising anodes for high-performance batteries with ultra-high specific energy density. However, uncontrolled dendrite growth and the unsuitability of common systems for high voltage hinder the development of Li metal batteries with long cycle life. Herein, we report a rationally designed artificial solid electrolyte interphase (SEI) for Li metal anodes, incorporating LiNO3 and lithium difluoro(oxalato)borate (LiDFOB) as additives within a porous poly (vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) polymer skeleton (referred to as PNF). LiNO3 and LiDFOB can release and synergistically react at the electrode surface, leading to the in situ generation of a homogeneously distributed inorganic/organic SEI during the electrochemical process. This SEI improves homogeneity, ionic conductivity and mechanical stability, contributing to the suppression of electrolyte side reactions and Li dendrite growth. Moreover, a uniform CEI with high Li+ conductivity can be constructed on the NCM811 particles, further enhancing the structural integrity of the NCM811 cathode. As a result, the artificial SEI layer on Li metal anodes enables stable cycling of Li-Cu half cells in an ester-based electrolyte and Li-LiNi0.8Mn0.1Co0.1O2 full cell even at a high voltage of 4.5 V. This work provides new insights into designing homogeneous SEIs for Li metal batteries.

In Situ Forming Asymmetric Gel Polymer Electrolyte Enhances the Performance of High-Voltage Lithium Metal Batteries.

With the rapid evolution of electric vehicle technology, concerns regarding range anxiety and safety have become increasingly pronounced. Battery systems with high specific energy and enhanced security, featuring ternary cathodes paired with lithium (Li) metal anodes, are poised to emerge as next-generation electrochemical devices. However, the asymmetric configuration of the battery structure, characterized by the robust oxidative behavior of the ternary cathodes juxtaposed with the vigorous reductive activity of the Li metal anodes, imposes elevated requisites for the electrolytes. Herein, a well-designed gel polymer electrolyte with asymmetric structure was successfully prepared based on the Ritter reaction of cyanoethyl poly(vinyl alcohol) (PVA-CN) and cationic ring-opening polymerization of s-Trioxane. With the aid of the sieving effect of separator, the in situ asymmetric gel polymer electrolyte has good compatibility with both the high-voltage cathodes and Li anodes. The amide groups generated by PVA-CN after the Ritter reaction and additional cyano groups can tolerate high voltages up to 5.1 V, matching with ternary cathodes without any challenges. The functional amide and cyano groups participate in the formation of the cathode electrolyte interface and stabilize the cathode structure. Meanwhile, the in situ formed ether-based polyformaldehyde electrolyte is beneficial for promoting uniform Li deposition on anode surfaces. Li-Li symmetric cells demonstrate sustained stability over 2000 h of cycling at a current density of 1 mA cm-2 for 1 mAh cm-2. Furthermore, the capacity retention rate of Li(Ni0.6Mn0.2Co0.2)O2-Li cells with 0.5 C cycling after 300 cycles is 92.2%, demonstrating excellent cycle stability. The electrolyte preparation strategy provides a strategy for the progress of high-performance electrolytes and promotes the rapid development of high-energy-density Li metal batteries.

Ultrafast growth of sulfurized 3D composite host for high−energy dendrite−free lithium metal batteries

Lithium metal anode of the highest theoretical specific capacity promises a high-energy-density of the built lithium metal batteries (LMBs). However, the attainable high-energy throughout its calendar life necessitates a suppressed irreversible lithium consumption by realizing a uniform nucleation and a dense growth of lithium on current collector. Herein, an improved lithium reversibility is demonstrated on a lithiophilic 3D copper foil. 3D Cu of abundant gullies created by a microwave-induced oxidative etching enables an instantaneous conformal sulfurization of the substrate in 5 s without exfoliation. The sulfurized surface (Cu@Cu2S) of improved affinity towards lithium and the 3D pattern of densified nucleation sites jointly promote a uniform lithium deposition. The synergistically regulated lithium nucleation/growth behavior significantly improves the cycling stability (up to 580 cycles) of the high-loading (up to 3.4 mAh cm−2) full cells and pouch cells. In form of anode-free pouch cell, the substantial deceases in both the thickness and areal density of the processed Cu foil further increase the energy density of such prototype by 19.3 % in gravimetry and 6.7 % in volumetry, reaching 446 Wh kg−1 and 1224 Wh L−1, respectively. This work proposes a scalable, straightforward and efficient strategy to realize the high-energy while enduring LMBs.

Covalent Organic Frameworks Interfacial Modification of Ceramic Electrolytes for Enhanced Electrochemical Performance

AbstractThe interface instability between inorganic ceramic electrolytes and lithium metal anodes seriously affects the cycling behavior of high‐performance lithium‐metal batteries. Herein, an in situ interfacial modification strategy is proposed to build the precise hybrid organic/inorganic lithium‐ion conducting layer where the Li1.3Al0.3Ti1.7(PO4)3 (LATP) particle surface is anchored by ion‐conducting covalent organic frameworks (COF) with affluent poly(ethylene glycol) (PEG) moieties. This interlayer features ion transport regulation to avoid high interfacial resistance and enhances interfacial stability by building a functional COF‐based shield against electrons. These as‐prepared particles are employed to fabricate flexible quasi‐solid electrolyte membranes interconnected by polytetrafluoroethylene binder based on the dry process. The obtained membranes perform two‐fold increase in ion conductivity at 30 °C of 2.55 × 10−3 S cm−1 and the prolonged lithium deposition up to 1000 h compared to the pristine, which are attributed to synergistic effects in the inorganic/organic phase. Moreover, an integrated cathode/electrolytes design is proposed and exhibits excellent cycling performance with capacity retention of 98.8% after 200 cycles at 1 C. The corresponding pouch cells can light up LED after bending and recovery. This research provides new insights into the great potential of fabricating soft ceramic‐based membranes in a low‐cost and green way for highly‐stable lithium‐metal batteries.