Polymer-Ion Interaction Prompted Quasi-Solid Electrolyte for Room-Temperature High-Performance Lithium-Ion Batteries.

Lithium-ion batteries using quasi-solid gel electrolytes (QSEs) have gained increasing interest due to their enhanced safety features. However, their commercial viability is hindered by low ionic conductivity and poor solid-solid contact interfaces. In this study, a QSE synthesized by in situ polymerizing methyl methacrylate (MMA) in 1,2-dimethoxyethane (DME)-based electrolyte is introduced, which exhibits remarkable performance in high-loading graphite||LiNi0.8Co0.1Mn0.1O2 (NCM811) pouch cells. Owing to the unique solvent-lacking solvation structure, the graphite exfoliation caused by the well-known solvent co-intercalation is prohibited, and this unprecedented phenomenon is found to be universal for other graphite-unfriendly solvents. The high ionic conductivity and great interfacial contact provided by DME enable the quasi-solid graphite||NCM811 pouch cell to demonstrate superior C-rate capability even at a high cathode mass loading (17.5 mg cm-2), surpassing liquid carbonate electrolyte cells. Meanwhile, the optimized QSE based on carbonates exhibits excellent cycle life (92.4% capacity retention after 1700 cycles at 0.5C/0.5C) and reliable safety under harsh conditions. It also outperforms liquid electrolytes in other high-energy-density batteries with larger volume change. These findings elucidate the polymer's pivotal role in QSEs, offering new insights for advancing quasi-solid-state battery commercialization.

Aggregate-Dominated Dilute Electrolytes with Low-Temperature-Resistant Ion-Conducting Channels for Highly Reversible Na Plating/Stripping.

Developing rechargeable batteries with high power delivery at low temperatures (LT) below 0 °C is significant for cold-climate applications. Initial anode-free sodium metal batteries (AFSMBs) promise high LT performances because of the low de-solvation energy and smaller Stokes radius of Na+, nondiffusion-limited plating/stripping electrochemistry, and maximized energy density. However, the severe reduction in electrolyte ionic conductivity and formation of unstable solid electrolyte interphase (SEI) hinder their practical applications at LT. In this study, a 2-methyltetrahydrofuran-based dilute electrolyte is designed to concurrently achieve an anion-coordinated solvation structure and impressive ionic conductivity of 3.58 mS cm-1 at -40 °C. The dominant aggregate solvates enable the formation of highly efficient and LT-resistant Na+ hopping channels in the electrolyte. Moreover, the methyl-regulated electronic structure in 2-methyltetrahydrofuran induces gradient decomposition toward an inorganic-organic bilayer SEI with high Na+ mobility, composition homogeneity, and mechanical robustness. As such, a record-high Coulombic efficiency beyond 99.9% is achieved even at -40 °C. The as-constructed AFSMBs sustain 300 cycles with 80% capacity maintained, and a 0.5-Ah level pouch cell delivers 85% capacity over 180 cycles at -25 °C. This study affords new insights into electrolyte formulation for fast ionic conduction and superior Na reversibility at ultralow temperatures.

Bipolar Textile Composite Electrodes Enabling Flexible Tandem Solid-State Lithium Metal Batteries.

A majority of flexible and wearable electronics require high operational voltage that is conventionally achieved by serial connection of battery unit cells using external wires. However, this inevitably decreases the energy density of the battery module and may cause additional safety hazards. Herein, a bipolar textile composite electrode (BTCE) that enables internal tandem-stacking configuration to yield high-voltage (6 to 12 V class) solid-state lithium metal batteries (SSLMBs) is reported. BTCE is comprised of a nickel-coated poly(ethylene terephthalate) fabric (NiPET) core layer, a cathode coated on one side of the NiPET, and a Li metal anode coated on the other side of the NiPET. Stacking BTCEs with solid-state electrolytes alternatively leads to the extension of output voltage and decreased usage of inert package materials, which in turn significantly boosts the energy density of the battery. More importantly, the BTCE-based SSLMB possesses remarkable capacity retention per cycle of over 99.98% over cycling. The composite structure of BTCE also enables outstanding flexibility; the battery keeps stable charge/discharge characteristics over thousands of bending and folding. BTCE shows great promise for future safe, high-energy-density, and flexible SSLMBs for a wide range of flexible and wearable electronics.

Extreme Fast Charging of Lithium Metal Batteries Enabled by a Molten-Salt-Derived Nanocrystal Interphase.

The extreme fast charging performance of lithium metal batteries (LMBs) with a long life is an important focus in the development of next-generation battery technologies. The friable solid electrolyte interphase and dendritic lithium growth are major problems. The formation of an inorganic nanocrystal-dominant interphase produced by preimmersing the Li in molten lithium bis(fluorosulfonyl)imide that suppresses the overgrowth of the usual interphase is reported. Its high surface modulus combined with fast Li+ diffusivity enables a reversible dendrite-proof deposition under ultrahigh-rate conditions. It gives a record-breaking cumulative plating/stripping capacity of >240 000 mAh cm-2 at 30 mA cm-2@30 mAh cm-2 for a symmetric cell and an extreme fast charging performance at 6 C for 500 cycles for a Li||LiCoO2 full cell with a high-areal-capacity, thus expanding the use of LMBs to high-loading and power-intensive scenarios. Its usability both in roll-to-roll production and in different electrolytes indicating the scalable and industrial potential of this process for high-performance LMBs.

Ultrathin, Mechanically Robust Quasi-Solid Composite Electrolyte for Solid-State Lithium Metal Batteries.

Herein, we present the preparation and properties of an ultrathin, mechanically robust, quasi-solid composite electrolyte (SEO-QSCE) for solid-state lithium metal battery (SLB) from a well-defined polystyrene-b-poly(ethylene oxide) diblock copolymer (SEO), Li6.75La3Zr1.75Ta0.25O12 nanofiller, and fluoroethylene carbonate plasticizer. Compared with the ordered lamellar microphase separation of SEO, the SEO-QSCE displays bicontinuous phases, consisting of a Li+ ion conductive poly(ethylene oxide) domain and a mechanically robust framework of the polystyrene domain. Therefore, the 12 µm-thick SEO-QSCE membrane exhibits an exceptional ionic conductivity of 1.3 × 10-3 S cm-1 at 30 °C, along with a remarkable tensile strength of 5.1 MPa and an elastic modulus of 2.7 GPa. The high mechanical robustness and the self-generated LiF-rich SEI enable the SEO-QSCE to have an extraordinary lithium dendrite prohibition effect. The SLB of Li|SEO-QSCE|LiFePO4 reveals superior cycling performances at 30 °C for over 600 cycles, maintaining an initial discharge capacity of 145 mAh g-1 and a remarkable capacity retention of 81% (117 mAh g-1) after 400 cycles at 0.5 C. The high-voltage SLB of Li|SEO-QSCE|LiNi0.5Co0.3Mn0.2O2 displays good cycling stability for over 150 cycles at 30 °C. Moreover, the exceptional robustness of SEO-QSCE enables the high-voltage solid-state pouch cell of Li|SEO-QSCE|LiNi0.5Co0.3Mn0.2O2 with high flexibility and excellent safety features. The current investigation delivers a promising and innovative approach for preparing quasi-solid electrolytes with features of ultrathin design, mechanical robustness, and exceptional electrochemical performance for high-voltage SLBs.

A logistic-tent chaotic mapping Levenberg Marquardt algorithm for improving positioning accuracy of grinding robot.

The precision of workpiece machining is critically influenced by the geometric errors in the kinematics of grind robots, which directly affect their absolute positioning accuracy. To tackle this challenge, this paper introduces a logistic-tent chaotic mapping Levenberg Marquardt algorithm designed to accurately identify and compensate for this geometric error. the approach begins with the construction of a forward kinematic model and an error model specific to the robot. Then the algorithm is adopted to identify and compensate for the geometric error. The method establishes a mapping interval around the initial candidate solutions derived from iterative applications of the Levenberg Marquardt algorithm. Within this interval, the logistic-tent chaotic mapping method generates a diverse set of candidate solutions. These candidates are evaluated based on their fitness values, with the optimal solution selected for subsequent iterations. Empirical compensation experiments have validated the proposed method's precision and effectiveness, demonstrating a 6% increase in compensation accuracy and a 47.68% improvement in efficiency compared to existing state-of-the-art approaches. This process not only minimizes the truncation error inherent in the Levenberg Marquardt algorithm but also significantly enhances solution efficiency. Moreover, simulation experiments on grind processes further validate the method's ability to significantly improve the quality of workpiece machining.

Regulating Electrolyte Solvation Structures via Diluent-Solvent Interactions for Safe High-Voltage Lithium Metal Batteries.

Local high concentration electrolytes (LHCEs) have been proved to be one of the most promising systems to stabilize both high voltage cathodes and Li metal anode for next-generation batteries. However, the solvation structures and interactions among different species in LHCEs are still convoluted, which bottlenecks the further breakthrough on electrolyte development. Here, it is demonstrated that the hydrogen bonding interaction between diluent and solvent is crucial for the construction of LHCEs and corresponding interphase chemistries. The 2,2,2-trifluoroethyl trifluoromethane sulfonate (TFSF) is selected as diluent with the solvent dimethoxy-ethane (DME) to prepare a non-flammable LHCE for high voltage LMBs. This is first find that the hydrogen bonding interaction between TFSF and DME solvent tailors the electrolyte solvation structures by weakening the coordination of DME molecules to Li+ cations and allows more participation of anions in the first solvation shell, leading to the formation of aggregates (AGGs) clusters which are conducive to generating inorganic solid/cathodic electrolyte interphases (SEI/CEIs). The proposed TFSF based LHCE enables the Li||NCM811 (LiNi0.8Mn0.1O2) batteries to realize >80% capacity retention with a high average Coulombic efficiency of 99.8% for 230 cycles under aggressive conditions (NCM811 cathode: 3.4 mAh cm-2, cut-off voltage: 4.4 V, and 20 µm Li foil).

Insight into Multiple Intermolecular Coordination of Composite Solid Electrolytes via Cryo-Electron Microscopy for High-Voltage All-Solid-State Lithium Metal Batteries.

Polymer/ceramic-based composite solid electrolytes (CSE) are promising candidates for all-solid-state lithium metal batteries (SLBs), benefiting from the combined mechanical robustness of polymeric electrolytes and the high ionic conductivity of ceramic electrolytes. However, the interfacial instability and poorly understood interphases of CSE hinder their application in high-voltage SLBs. Herein, a simple but effective CSE that stabilizes high-voltage SLBs by forming multiple intermolecular coordination interactions between polyester and ceramic electrolytes is discovered. The multiple coordination between the carbonyl groups in poly(ε-caprolactone) and the fluorosulfonyl groups in anions with Li6.5La3Zr1.5Ta0.5O12 nanoparticles is directly visualized by cryogenic transmission electron microscopy and further confirmed by theoretical calculation. Importantly, the multiple coordination in CSE not only prevents the continuous decomposition of polymer skeleton by shielding the vulnerable carbonyl sites but also establishes stable inorganic-rich interphases through preferential decomposition of anions. The stable CSE and its inorganic-rich interphases enable Li||Li symmetric cells with an exceptional lifespan of over 4800 h without dendritic shorting at 0.1 mA cm-2. Moreover, the high-voltage SLB with LiNi0.5Co0.2Mn0.3O2 cathode displays excellent cycling stability over 1100 cycles at a 1C charge/discharge rate. This work reveals the underlying mechanism behind the excellent stability of coordinating composite electrolytes and interfaces in high-voltage SLBs.

A Review of Emerging Technologies in Ultra-Smooth Surface Processing for Optical Components.

Advancements in astronomical telescopes and cutting-edge technologies, including deep ultraviolet (DUV) and extreme ultraviolet (EUV) lithography, have escalated demands and imposed stringent surface quality requirements on optical system components. Achieving near-ideal optical components requires ultra-smooth surfaces with sub-nanometer roughness, no sub-surface damage, minimal surface defects, low residual stresses, and intact lattice integrity. This necessity has driven the rapid development and diversification of ultra-smooth surface fabrication technologies. This paper summarizes recent advances in ultra-smooth surface processing technologies, categorized by their material removal mechanisms. A subsequent comparative analysis evaluates the roughness and polishing characteristics of ultra-smooth surfaces processed on various materials, including fused silica, monocrystalline silicon, silicon carbide, and sapphire. To maximize each process's advantages and achieve higher-quality surfaces, the paper discusses tailored processing methods and iterations for different materials. Finally, the paper anticipates future development trends in response to current challenges in ultra-smooth surface processing technology, providing a systematic reference for the study of the production of large-sized freeform surfaces.

Beyond LiF: Tailoring Li2O-Dominated Solid Electrolyte Interphase for Stable Lithium Metal Batteries.

The components and structures of the solid-electrolyte interphase (SEI) are critical for stable cycling of lithium metal batteries (LMBs). LiF has been widely studied as the dominant component of SEI, but Li2O, which has a much lower diffusion barrier for Li+, has rarely been investigated as the dominant component of SEI. The effect of Li2O-dominated SEI on electrochemical performance still remains elusive. Herein, an ultrastrong coordinated cosolvation diluent, 2,3-difluoroethoxybenzene (DFEB), is designed to modulate solvation structure and tailor Li2O-dominated SEI for stable LMBs. In the DFEB-based LHCE (DFEB-LHCE), DFEB intensively participates in the first solvation shell and synergizes with FSI- to tailor an Li2O-dominated inorganic-rich SEI which is different from the LiF-dominated SEI formed in conventional LHCE. Benefiting from this special SEI architecture, a high Coulombic efficiency (CE) of 99.58% in Li||Cu half cells, stable voltage profiles, and dense and uniform lithium deposition, as well as effective inhibition of Li dendrite formation in the symmetrical cell, are achieved. More importantly, the DFEB-LHCE can be matched with various cathodes such as LFP, NCM811, and S cathodes, and the Li||LFP full cell using DFEB-LHCE possesses 85% capacity retention after 650 stable cycles with 99.9% CE. Especially the 1.5 Ah practical lithium metal pouch cell achieves an excellent capacity retention of 89% after 250 cycles with a superb average CE of 99.93%. This work unravels the superiority of the Li2O-dominated SEI and the feasibility of tailoring SEI components through modulation of solvation structures.

Restructuring Electrolyte Solvation by a Versatile Diluent Toward Beyond 99.9% Coulombic Efficiency of Sodium Plating/Stripping at Ultralow Temperatures.

The reversible and durable operation of sodium metal batteries at low temperatures (LT) is essential for cold-climate applications but is plagued by dendritic Na plating and unstable solid-electrolyte interphase (SEI). Current Coulombic efficiencies of sodium plating/stripping at LT fall far below 99.9%, representing a significant performance gap yet to be filled. Here, the solvation structure of the conventional 1 m NaPF6 in diglyme electrolyte by facile cyclic ether (1,3-dioxolane, DOL) dilution is efficiently reconfigured. DOL diluents help shield the Na+-PF6 - Coulombic interaction and intermolecular forces of diglyme, leading to anomalously high Na+-ion conductivity. Besides, DOL participates in the solvation sheath and weakens the chelation of Na+ by diglyme for facilitated desolvation. More importantly, it promotes concentrated electron cloud distribution around PF6 - in the solvates and promotes their preferential decomposition. A desired inorganic-rich SEI is generated with compositional uniformity, high ionic conductivity, and high Young's modulus. Consequently, a record-high Coulombic efficiency over 99.9% is achieved at an ultralow temperature of -55 °C, and a 1 Ah capacity pouch cell of initial anode-free sodium metal battery retains 95% of the first discharge capacity over 100 cycles at -25 °C. This study thus provides new insights for formulating electrolytes toward increased Na reversibility at LT.

A novel method for improving optical component smoothing quality in robotic smoothing systems by compensating path errors.

Path deviations caused by geometrical errors in machining equipment significantly affect the machining quality of optical components. To enhance the quality and efficiency of optical component processing, this paper presents a Chebyshev interpolated Levenberg-Marquardt algorithm (CILM) aimed at compensating for path deviations in a robotic smoothing system utilized for optical component processing. First, the positioning accuracy of the robotic smoothing system is measured using a laser tracker. Subsequently, an objective function is constructed based on robot kinematics and error models to optimize the geometric errors in the system. Then, the proposed method is adopted to identify the geometric parameters of the robotic smoothing system to compensate for the smoothing path deviations. The compensation results confirm the effectiveness of the proposed method in enhancing the absolute positioning accuracy of the robotic smoothing system. Additionally, experimental verification is conducted to validate the effectiveness of the proposed method in improving the surface quality of optical components through smoothing path compensation. The results of the three experiments indicate that the proposed CILM achieves optical components with peak-to-valley values 15.70%, 28.7%, and 4.01% lower than those obtained before compensation, along with root mean square of 33.67%, 21.57%, and 10.23% lower than before compensation values, respectively. Moreover, the power spectral density curves of CILM exhibit smoother characteristics in comparison to the curves before compensation.

Polymer-in-Salt Electrolyte from Poly(caprolactone)-graft-polyrotaxane for Ni-Rich Lithium Metal Batteries at Room Temperature.

Solid-state lithium batteries with solid polymer electrolytes have recently attracted extensive attention due to their promising potential in high energy density and safety. However, the principal issues plaguing the solid polymer electrolytes are their restricted ionic conductivities at ambient temperature and the limited tolerance to the widely used high-voltage cathodes (such as LiNi0.8Mn0.1Co0.1O2, NCM811), thus limiting their practical applications seriously. In this regard, a superior polymer-in-salt solid electrolyte from poly(caprolactone)-graft-polyrotaxane (PGPE) is developed for high-voltage lithium batteries operated at room temperature. The PGPE displays remarkable electrochemical properties at room temperature, with an exceptional ionic conductivity of 4.89 × 10-4 S cm-1 and a lithium-ion transference number of approximately 0.64, stemming from the rapid segmental motions of PCL sidechains by the enhanced dynamics of the cyclic molecules along the axial polymer chain of polyrotaxane. More importantly, the PGPE demonstrates a high electrochemical oxidation voltage of ∼4.7 V, suggesting the excellent electrochemical stability of PGPE against the NCM811-based cathode. Owing to the dense LiF-rich CEI self-generated on the NCM811 particles in the cathode, the transition metal ion diffusion is successfully constrained and the PGPE is well protected from continuous decomposition. The PGPE also shows superior interfacial stability between the metallic Li and the electrolyte. As a result, the all-solid-state NCM811|PGPE|Li cell exhibits superior discharge capacity (196 mAh g-1) and extraordinary long-term cycling stability (74% capacity retention at 150 cycles) at 30 °C.

Self-Assembly Monolayer Inspired Stable Artificial Solid Electrolyte Interphase Design for Next-Generation Lithium Metal Batteries.

Lithium metal is widely regarded as the "ultimate" anode for energy-dense Li batteries, but its high reactivity and delicate interface make it prone to dendrite formation, limiting its practical use. Inspired by self-assembled monolayers on metal surfaces, we propose a facile yet effective strategy to stabilize Li metal anodes by creating an artificial solid electrolyte interphase (SEI). Our method involves dip-coating Li metal in MPDMS to create an SEI layer that is rich in inorganic components, allowing uniform Li plating/stripping under a low overpotential over 500 cycles in carbonate electrolytes. In comparison, pristine Li metal shows a rapid increase in overpotential after merely 300 cycles, leading to failure soon after. Molecular dynamics simulations demonstrate that this uniform artificial SEI suppresses Li dendrite formation. We further demonstrated its enhanced stability pairing with LiFePO4 and LiNi1-x-yCoxMnyO2 cathodes, highlighting the proposed strategy as a promising solution for practical Li metal batteries.

A monofluoride ether-based electrolyte solution for fast-charging and low-temperature non-aqueous lithium metal batteries.

The electrochemical stability window of the electrolyte solution limits the energy content of non-aqueous lithium metal batteries. In particular, although electrolytes comprising fluorinated solvents show good oxidation stability against high-voltage positive electrode active materials such as LiNi0.8Co0.1Mn0.1O2 (NCM811), the ionic conductivity is adversely affected and, thus, the battery cycling performance at high current rates and low temperatures. To address these issues, here we report the design and synthesis of a monofluoride ether as an electrolyte solvent with Li-F and Li-O tridentate coordination chemistries. The monofluoro substituent (-CH2F) in the solvent molecule, differently from the difluoro (-CHF2) and trifluoro (-CF3) counterparts, improves the electrolyte ionic conductivity without narrowing the oxidation stability. Indeed, the electrolyte solution with the monofluoride ether solvent demonstrates good compatibility with positive and negative electrodes in a wide range of temperatures (i.e., from -60 °C to +60 °C) and at high charge/discharge rates (e.g., at 17.5 mA cm-2). Using this electrolyte solution, we assemble and test a 320 mAh Li||NCM811 multi-layer pouch cell, which delivers a specific energy of 426 Wh kg-1 (based on the weight of the entire cell) and capacity retention of 80% after 200 cycles at 0.8/8 mA cm-2 charge/discharge rate and 30 °C.

Inhibiting Formation and Reduction of Li2 CO3 to LiCx at Grain Boundaries in Garnet Electrolytes to Prevent Li Penetration.

Poor ion and high electron transport at the grain boundaries (GBs) of ceramic electrolytes are the primary reasons for lithium filament infiltration and short-circuiting of all-solid-state lithium metal batteries (ASLMBs). Herein, it is discovered that Li2 CO3 at the GBs of Li7 La3 Zr2 O12 (LLZO) sheets is reduced to highly electron-conductive LiCx during cycling, resulting in lithium penetration of LLZO. The ionic and electronic conductivity of the GBs within LLZO can be simultaneously tuned using sintered Li3 AlF6 . The generated LiAlO2 (LAO) infusion and F-doping at the GBs of LLZO (LAO-LLZOF) significantly reduce the Li2 CO3 content and broaden the energy bandgap of LLZO, which decreases the electronic conductivity of LAO-LLZOF. LAO forms a 3D continuous ion transport network at the GB that significantly improves the total ionic conductivity. Lithium penetration within LLZO is suppressed and an all-solid-state LiFePO4 /LAO-LLZOF/Li battery stably cycled for 5500 cycles at 3 C. This work reveals the chemistry of Li2 CO3 at the LLZO GBs during cycling, presents a novel lithium penetration mechanism within garnet electrolytes, and provides an innovative method to simultaneously regulate the ion and electron transport at the GBs in garnet electrodes for advanced ASLMBs.

Fundamentals of the Cathode-Electrolyte Interface in All-solid-state Lithium Batteries.

All-solid-state lithium batteries (ASSBs) enabled by solid-state electrolytes (SEs) including oxide-based and sulfide-based electrolytes have gained worldwide attention because of their intrinsic safety and higher energy density over conventional lithium-ion batteries (LIBs). However, despite the high ionic conductivity of advanced SEs, ASSBs still exhibit high overall internal resistance, the most significant contributor of which can be ascribed to the cathode-SE interfaces. This review seeks to clarify the critical issues regarding the cathode-SE interfaces, including fundamental principles and corresponding solutions. First, major issues concerning electro-chemo-mechanical instability between cathodes and SEs and their formation mechanisms are discussed. Then, specific problems in oxides and sulfides and various solutions and strategies toward interfacial modifications are highlighted. Efforts toward the characterization and analysis of cathode-SE interfaces with advanced techniques are also summarized. Finally, perspectives are offered on several problems demanding urgent solutions and the future development of SE applications and ASSBs.

Biobased Self-Growing Approach toward Tailored, Integrated High-Performance Flexible Lithium-Ion Battery.

Here we present an innovative, universal, scalable, and straightforward strategy for cultivating a resilient, flexible lithium-ion battery (LIB) based on the bacterial-based self-growing approach. The electrodes and separator layers are integrated intrinsically into one unity of sandwich bacterial cellulose integrated film (SBCIF), with various active material combinations and tailored mechanical properties. The flexible LIB thereof showcases prominent deformation tolerance and multistage foldability due to the unique self-generated wavy-like structure. The LTO|LFP (Li4Ti5O12 and LiFePO4) SBCIF-based flexible LIB demonstrates reliable long-term electrochemical stability with high flexibility, by exhibiting a high capacity retention (>95%) after 500 cycles at 1C/1C after experiencing a 10 000 bending/flattening treatment. The LTO|LFP SBCIF battery subjected to a simultaneous bending/flattening and cycling experiment shows an extraordinary capacity retention rate (>68%) after 200 cycles at 1C/1C. The biobased self-growing approach offers an exciting and promising pathway toward the tailored, integrated high-performance flexible LIBs.

Roll-To-Roll Fabrication of Zero-Volume-Expansion Lithium-Composite Anodes to Realize High-Energy-Density Flexible and Stable Lithium-Metal Batteries.

The lithium (Li)-metal anode offers a promising solution for high-energy-density lithium-metal batteries (LMBs). However, the significant volume expansion of the Li metal during charging results in poor cycling stability as a result of the dendritic deposition and broken solid electrolyte interphase. Herein, a facile one-step roll-to-roll fabrication of a zero-volume-expansion Li-metal-composite anode (zeroVE-Li) is proposed to realize high-energy-density LMBs with outstanding electrochemical and mechanical stability. The zeroVE-Li possesses a sandwich-like trilayer structure, which consists of an upper electron-insulating layer and a bottom lithiophilic layer that synergistically guides the Li deposition from the bottom up, and a middle porous layer that eliminates volume expansion. This sandwich structure eliminates dendrite formation, prevents volume change during cycling, and provides outstanding flexibility to the Li-metal anode even at a practical areal capacity over 3.0 mAh cm-2 . Pairing zeroVE-Li with a commercial NMC811 or LCO cathode, flexible LMBs that offer a record-breaking figure of merit (FOM, 45.6), large whole-cell energy density (375 Wh L-1 , based on the volume of the anode, separator, cathode, and package), high-capacity retention (> 99.8% per cycle), and remarkable mechanical robustness under practical conditions are demonstrated.