Dendrite-free Li Deposition Research Articles

Self-Healing Nucleation Seeds Induced Long-Term Dendrite-Free Lithium Metal Anode.

Seeded lithium (Li) nucleation has been considered as a promising strategy to achieve uniform Li deposition. However, problems of agglomeration and pulverization quickly invalidate the nucleation seeds, resulting in Li dendrite growth during repeated charge/discharge processes. Herein, liquid gallium-indium (GaIn) nanoparticles with structural self-healing properties are utilized to guide uniform metallic Li nucleation and deposition. Ultrafine GaIn nanoparticles (∼25 nm) uniformly decorated on the surface of carbon layers effectively homogenize the lithium-ion flux. After fully Li stripping, lithiophilic GaIn nanoparticles return to the liquid binary eutectic phase, thereby healing the deformed structure and enabling them to continuously guide dendrite-free Li deposition. Li metal anodes with such nucleation seeds exhibit nearly zero nucleation overpotential even after hundreds of cycles and a high average Coulombic efficiency of 99.03% for more than 400 cycles. The design of self-healing nucleation seeds provides important insights for obtaining high-performance lithium metal anodes.

Molybdenum host and interphase induced decentralized lithium deposition for dendrite-free lithium metal anodes

Lithium metal anode confronts great challenge of dendrite growth and safety hazard to reform present lithium ion batteries. Constructing advanced Li/host composite anode is an effective approach to settle these issues. However, the intrinsic characteristics of host substrates have not been carefully investigated, which can extremely affect the interactions of Li atoms and thereby alter Li deposition morphology. Herein, we propose metallic Mo as a specific host to fabricate Li/Mo anode to promote dendrite-free Li deposition. Density functional theory results reveal that the deposited Li atoms tend to mutually repulse on Mo substrate, while present interattraction on Li substrate. Benefiting from the positive effects of 3D Mo host and interphase, Li/Mo anode exhibits decentralized deposition with granular morphology, differs from severe dendrite growth on bare Li. Besides, the anode delivers stable cycling lifespan and low voltage hysteresis with only 25 mV after 800 h at 2 mA cm−2 with capacity of 1 mAh cm−2 in symmetric batteries. Matching with LiFePO4 cathode, the full cells exhibit superior electrochemical performance in both ether- and more corrosive carbonate-based electrolytes. This exploration offers a new research orientation for developing more appropriate hosts for metallic anodes.

Flexible and stable 3D lithium metal anodes based on self-standing MXene/COF frameworks for high-performance lithium-sulfur batteries

Lithium metal (Li) is believed to be the ultimate anode for lithium-ion batteries (LIBs) owing to the advantages of high theoretical capacity, the lowest electrochemical potential, and light weight. Nevertheless, issues such as uncontrollable growth of Li dendrites, large volume changes, high chemical reactivity, and unstable solid electrolyte interphase (SEI) hinder its rapid development and practical application. Herein a stable and dendrite-free Li-metal anode is obtained by designing a flexible and freestanding MXene/COF framework for metallic Li. COF-LZU1 microspheres are distributed among the MXene film framework. Lithiophilic COF-LZU1 microspheres as nucleation seeds can promote uniform Li nucleation by homogenizing the Li+ flux and lowering the nucleation barrier, finally resulting in dense and dendrite-free Li deposition. Under the regulation of the COF-LZU1 seeds, the Coulombic efficiency of the MXene/COF-LZU1 framework and electrochemical stability of corresponding symmetric cells are obviously enhanced. Li-S full cells with the modified Li-metal anode and sulfurized polyacrylonitrile (S@PAN) cathode also exhibited a superior electrochemical performance.

Self-leveling electrolyte enabled dendrite-free lithium deposition for safer and stable lithium metal batteries

Lithium (Li) metal is considered an ideal anode material for future high-energy rechargeable batteries. However, the extremely unstable interfaces between lithium anode and electrolyte induce uncontrollable dendrite formation and low Coulombic efficiency, retarding its practical applications in Li metal batteries (LMB). Herein, we propose a facile and feasible strategy of introducing 12-Crown-4 ether as a leveling additive into the electrolyte to inherently eliminate the self-amplification behavior of dendrite growth. The Li+–additive complexes with low electron-accepting ability are preferentially adsorbed on the initial protuberant tips of Li metal surface, which can effectively regulate the local polarization resistance and improve the current distribution uniformity. Based on this principle, a self-leveling electrolyte comprising fluoroethylene carbonate (FEC) solvent and 12-Crown-4 additive is developed. Dense and dendrite-free Li deposition, as well as enhanced interfacial stability is achieved in such electrolyte, rendering a significantly improved Coulombic efficiency (97.24%) in Li||Cu cells and a superior cycling stability in Li||Li cells. Moreover, a Li metal full-cell with high-loading LiFePO4 cathode (12.5 mg cm−2) retains 98% capacity after 100 cycles at 0.5 C. This self-leveling electrolyte approach opens up new perspective on the mechanistic and methodological aspects for designing safer lithium metal batteries.

Bifunctional Fluorinated Separator Enabling Polysulfide Trapping and Li Deposition for Lithium-Sulfur Batteries.

Lithium-sulfur batteries (LSBs) are deemed as one of the most promising next generation energy storage system substitutes for conventional lithium ion batteries due to their high energy density, low cost, and environmental friendliness. The practical application of LSBs has long been blocked by the serious lithium polysulfide (LiPS) shuttle effect and notorious Li dendrite growth, inducing fast capacity decay and limited cycling lifespan. Herein, fluorinated carbon prepared via a safe and scalable strategy has rationally been coated on a separator affording bifunctional fluorinated Celgard (F-Celgard) for LSB construction. The F-Celgard shows superior Li+ flux modulation and LiPS trapping capability, which has been verified by the density function theory calculations. The Li symmetric cells demonstrate long and stable Li plating/stripping with much smaller polarization voltage and dendrite-free Li deposition. In addition, LSBs show superior rate performances with higher discharge capacities and long-time stable cycling over 1000 cycles at 1 C with a low decay rate of ∼0.038% per cycle. With a high sulfur loading (∼5.2 mg cm-2), a high initial areal capacity of ∼4.2 mAh cm-2 can be obtained with a superior capacity retention of ∼91.8% at 0.2 C. This work demonstrates a facile, cost-effective, and scalable strategy toward highly stable LSBs for practical usage.

Regulating alkali metal deposition behavior via Li/Na-philic Ni nanoparticles modified 3D hierarchical carbon skeleton

Alkali metal anodes are promising anodes for constructing novel battery systems with high energy density. Nevertheless, limited nucleation sites and nonuniform local electric field caused dendrites growth and unlimited volume expansion hindered their practical implementation during electrochemical plating/stripping. Herein, a 3D N-doped carbon nanofiber skeleton wrapped with Ni nanoparticles encapsulated carbon nanotubes (CNTs-Ni@NCFs) is prepared by hydrothermal process and followed catalytic reaction under ethanol atmosphere to construct a superior Li/Na-philic host with stable chemical properties. The 3D NCF networks serve as a primary framework, providing sufficient voids for alkali metal deposition and rapid electron and ion transport. The Li/Na-philic Ni nanoparticles and catalyzed CNTs on CFs provide evenly distributed nucleation sites and uniform local electric field, leading to dendrite-free Li deposition, which is confirmed by theoretical calculations. Because of the guided deposition behavior and bare volume change, the CNTs-Ni@NCFs anode delivers an extremely low nucleation overpotential in the initial deposition and a superior plating/stripping voltage hysteresis under a high current density of 30 mA cm−2 for 300 cycles. The CNTs-Ni@NCFs-Li full cell with LiFePO4 cathodes demonstrates 94.2% capacity retention after 200 cycles under 2 C. When coupled with Na3V2(PO4)3 cathode, the CNTs-Ni@NCFs-Na cell shows a good suitability in full cell. This work shed new light on fabricating novel stable alkali metal anodes, which may also pave the way toward to other practical applications with high energy densities, such as in Li-air and Li-S batteries, etc.

An aqueous polyethylene oxide-based solid-state electrolyte with high voltage stability for dendrite-free lithium deposition via a self-healing electrostatic shield.

Lithium metal batteries (LMBs) have attracted extensive attention for their ultrahigh energy density. However, the uncontrollable growth of Li-dendrites results in poor cyclability and potential safety risks, thus preventing their practical application. Herein, a flexible and cost-effective aqueous polyethylene oxide (PEO)-based solid-state electrolyte is prepared, which enables uniform and dendrite-free Li deposition by introducing Cs+ with an electrostatic shielding mechanism at high current densities. The self-assembly of PEO and bacterial cellulose by hydrogen bonding reduces the crystallinity of PEO and increases uniformly the distribution of lithium ions. With excellent flexibility and thermal stability, such a 3D polymer solid-state electrolyte exhibits an enhanced electrochemical stability window of 5.8 V versus Li/Li+ potential and a high ionic conductivity of 1.28 × 10-4 S cm-1 at 60 °C. The Li|BC-PEO-Cs+|Li symmetric cells operate stably for more than 1000 h. Furthermore, Li|BC-PEO-Cs+|LiFePO4 (LFP) cells show remarkable enhancement in capacity (163.4 mA h g-1 at 0.1 C), cycling stability (with a capacity retention of 96% after 500 cycles at 1 C) and high functionality and safety (withstanding folding and cutting) in practical applications.

Lithiophilic Sb surface modified Cu nanowires grown on Cu foam: a synergistic 1D@3D hierarchical structure for stable lithium metal anodes

A hierarchical structured 1D@3D-Cu/Sb Li host with a large specific surface area and good lithiophilicity was fabricated to achieve dendrite-free Li deposition and improve the long-term cycling stability of a Li metal anode.

Extraordinary dendrite-free Li deposition on highly uniform facet wrinkled Cu substrates in carbonate electrolytes

Despite much research focused on lithium (Li) metal batteries, an important issue concerning Li-dendrite growth on the anode remains unresolved. The intrinsic mechanism of this Li-dendrite formation is related to the non-uniform distribution of Li-ion flux on the anode in charge/discharge caused by irregular structure and energy of anode surface. Here we report upon dendrite-free Li-deposition in a carbonate-based electrolyte using a novel Cu anode structure with sharp wrinkles and a [100] crystal facet. This uniform Li-deposition resulted in long-term electrochemical cyclability in Li/Cu and LiFePO 4 /Li cell. Our observations revealed that the wrinkled Cu surface and the unifying [100] crystal facet play important roles in enhancing the uniformity of the Li-ion flux and the adsorption energy of the Li-ions on Cu, respectively. We expect that this study will permit the use of a wide range of wrinkled structures and crystal planes to obtain high-energy and long-term cycles of Li-metal batteries. • Dendrite-free Li deposition is obtained using wrinkled Cu with uniform [100] facet. • Wrinkled surface structure on Cu provides uniform Li + flux for uniform Li deposition. • Uniform [100] facet distribution equalizes Li adsorption energy on the Cu. • The uniform Li deposition resulted in long-term cyclability with 99% CE.

Silicious nanowires enabled dendrites suppression and flame retardancy for advanced lithium metal anodes

The ultrahigh-energy-density lithium (Li) metal anodes have received increasing attentions for developing next-generation Li batteries, nevertheless, the safety concern and interior cycling stability originated from the intrinsically dendritic Li plating, have greatly hinder their further applications. Herein, three-dimensional networks assembled form the mineral xonotlite (Ca6Si6O17(OH)2) nanowires (XNs) with high specific surface area, strong electrolyte affinity and flame-retardant property are designed to homogenize the Li+ flux and alleviate the dendrite-caused safety hazards. Moreover, this lithiophilic scaffold promises a homogeneous Li nucleation. Particularly, a small percentage of XNs reacts into LixSiOy which accumulates in the solid electrolyte interphase (SEI) as cycling. Aided by the atomic visualization from cryo-transmission electron microscopy, the monoclinic phase of crystalline Li4SiO4 in SEI is identified, which exhibits a Li+ conduction 1000 times higher than that of Li2O according to the molecular dynamic simulation. Hence, the regulated SEI with excellent Li+ transfer capability reduces the preferential growth of high-energy Li facets, thus realizing dendrite-free Li deposition. When paired with unstable LiNi0.8Co0.1Mn0.1O2 (NCM811) cathode, the full cells of Li-XNs-NCM811 show a capacity retention of 88% after ultralong 1600 h. This strategy would provide inspirations on rational design towards high-safety long-cycling Li metal batteries.

Highly efficient lithium utilization in lithium metal full-cell by simulated missile guidance and confinement systems

The efficient utilization of metallic lithium (Li) is the key to enable application of Li metal full-cell with low amount of excess Li, contributing to higher safety and energy density. Herein, we report an extraordinary Li metal full-cell with only 20% excess Li, which demonstrated significantly improved reversibility and high Coulombic efficiency. Ingenious simulated missile guidance and confinement system (SMGCS) was designed to guide and confine Li deposition through constructing compatible silver lithiophilic sites and nitrate layer. Silver sites act as effective Li nuclei to attract Li ions and direct the initial nucleation. The generated nitrate layer affords an interfacial environment favorable for confined and uniform deep Li deposition, which is theoretically verified by molecular dynamics (MD) simulations. The two combined merits offer a robust and dendrite-free Li deposition, enabling the application of Li metal full-cell with slight excess Li. They also result in an outperformed Li cycling efficiency of ca. 99% for over 300 cycles along with deep cycling at a high capacity of 10 mA h cm−2 in carbonate electrolytes. The unprecedented high degree of Li utilization opens a new avenue for the future development of highly efficient Li metal full cells.

Regulating the Li+ -Solvation Structure of Ester Electrolyte for High-Energy-Density Lithium Metal Batteries.

The development of high-energy-density Li metal batteries are hindered by electrolyte consumption and uneven lithium deposition due to the unstable lithium-electrolyte interface (SEI). In this work, tetraglyme is introduced into ester electrolyte to regulate the Li+ -solvation structures for stable SEI while remaining appropriate voltage window for high-voltage cathodes. In the modified solvation structures, an enhanced lowest unoccupied molecular orbital energy level occurs, resulting in relieved electrolyte degradation. In addition, the modified solvation structures can facilitate adequate LiNO3 dissolution in the ester electrolyte (denoted as E-LiNO3 ), contributing to constant supplement of constructing highly conductive LiNx Oy -containing SEI for dendrite-free Li deposition under high capacity condition. As a result, the Li||Cu cell-based on this electrolyte exhibits high Li plating/stripping Coulombic efficiency of 98.2% over 350 cycles. Furthermore, when paired with high-voltage LiNi0.5 Co0.2 Mn0.3 O2 cathodes, the E-LiNO3 enables a stable cycling with a high-energy-density of 296Wh kg-1 based on the full cell under realistic testing conditions (lean electrolyte of 3 gAh-1 , limited Li excess of 2.45-fold, and high areal capacity of 4 mAh cm-2 ).

Fluoroethylene carbonate-Li-ion enabling composite solid-state electrolyte and lithium metal interface self-healing for dendrite-free lithium deposition

Solid-state Li-metal batteries have attracted much attention owing to the high energy density and safety afforded by Li-metal anode and solid-state electrolytes. However, Li-dendrite penetration and unstable interface between solid-state electrolyte and Li-metal incumber their application. Herein, fluoroethylene carbonate (FEC) added Li0.35La0.55TiO3-Poly (ethylene oxide) (LLTO-(PEO-FEC)) composite solid-state electrolytes (CSSEs) are fabricated to address the bottlenecks. The CSSE possesses high Li+ conductivity of 1.13 × 10−4 S·cm−1 vs low electronic conductivity of 1.68 × 10−9 S·cm−1 at 25 °C, presents a wide electrochemical window of 5.2 V (vs. Li+/Li), and shows much more stable lithium deposition at current density of 0.2 mA·cm−2 for 800 h. FEC is driven by Li+ to the damaged interface to form new LiF-rich interface layer, which enables the self-healing of Li-metal and CSSE interface and enhances the electrochemical stability of CSSEs against Li-metal. Li| (LLTO-(PEO-FEC)) |LiFePO4 cell presents discharge capability of about 115 mAh·g−1 after 100 cycles at 50 °C. This work reveals the mechanism of dendrite-free Li deposition via interface self-healing process under the effect of FEC–Li+ coordination and provides a promising way to prepare the high performances composite solid-state electrolytes and to fabricate the dendrite-free all-solid-state lithium battery.

Nanopile Interlocking Separator Coating toward Uniform Li Deposition of the Li Metal Anodes.

Uncontrollable growth of lithium (Li) dendrite has severely hindered the development of Li metal anodes, while separator modification is regarded as a simple and effective way to mitigate the growth of Li dendrite. However, the "drop-dregs" phenomenon of coating layer desquamated from polyolefin separator due to their different Young's modulus would induce a nonuniform Li ionic flux, finally resulting in deteriorative electrochemical performance and even thermal runaway of the battery. Herein, we introduce a novel nanopile mechanical interlocking strategy to create delamination-free separator modification, which could stably generate a homogeneous Li ionic flux to guide long-term uniform Li deposition. Both experimental and simulation results demonstrate a strong bonding strength between the coating layer and membrane matrix based on this physical interlocking mechanism. Consequently, with a nearly dendrite-free Li deposition and a largely reduced interface impedance, 1000 h stable cycling of Li/Li half cells enrolled this modified separator is successfully achieved. Also, a significant improvement in Li/LiFePO4 full cells in long-term cycling stability to 500 cycles further indicates its promising practical potential. Moreover, this presented approach without any binding agents or surface activation procedures could be facilely scaled up, providing an applicable and durable separator modification solution toward stable Li metal anodes.

Hybrid solid electrolyte enabled dendrite-free Li anodes for high-performance quasi-solid-state lithium-oxygen batteries.

The dendrite growth of Li anodes severely degrades the performance of lithium-oxygen (Li-O2) batteries. Recently, hybrid solid electrolyte (HSE) has been regarded as one of the most promising routes to tackle this problem. However, before this is realized, the HSE needs to simultaneously satisfy contradictory requirements of high modulus and even, flexible contact with Li anode, while ensuring uniform Li+ distribution. To tackle this complex dilemma, here, an HSE with rigid Li1.5Al0.5Ge1.5(PO4)3 (LAGP) core@ultrathin flexible poly (vinylidene fluoride-hexafluoropropylene) (PVDF-HFP) shell interface has been developed. The introduced large amount of nanometer-sized LAGP cores can not only act as structural enhancer to achieve high Young's modulus but can also construct Li+ diffusion network to homogenize Li+ distribution. The ultrathin flexible PVDF-HFP shell provides soft and stable contact between the rigid core and Li metal without affecting the Li+ distribution, meanwhile suppressing the reduction of LAGP induced by direct contact with Li metal. Thanks to these advantages, this ingenious HSE with ultra-high Young's modulus of 25 GPa endows dendrite-free Li deposition even at a deposition capacity of 23.6 mAh. Moreover, with the successful inhibition of Li dendrites, the HSE-based quasi-solid-state Li-O2 battery delivers a long cycling stability of 146 cycles, which is more than three times that of gel polymer electrolyte-based Li-O2 battery. This new insight may serve as a starting point for further designing of HSE in Li-O2 batteries, and can also be extended to various battery systems such as sodium-oxygen batteries.

Three-Dimensional Ordered Macro/Mesoporous Cu/Zn as a Lithiophilic Current Collector for Dendrite-Free Lithium Metal Anode.

Li dendrites are considered as the primary cause for degradation and inevitable short circuit in lithium-metal batteries (LMBs). Although contemporary strategies have shown potential for addressing dendrite growth, none have achieved complete elimination. In this paper, a dendrite-free, three-dimensional, ordered, macro/mesoporous Cu/Zn current collector was prepared using a combination of simple colloidal crystal template and electrochemical method (electrodeposition and pulse plating). When paired with a hierarchically structured mesoporous (20-50 nm) and macroporous (450 nm) anode, this novel current collector achieved stable charge/discharge cycles of over 2000 h and a small plating/stripping potential (≈8 mV) at a current density of 0.2 mA cm-2. Coulombic efficiencies (CE) also reached 94.7% after 400 cycles. This three-dimensional, ordered, macro/mesoporous structure provides a greater specific surface area, reduces local current density, and contains a lithiophilic Zn coating that serves as preferred Li nucleation sites. By combining these factors, dendrite-free Li deposition and superior electrochemical performance improvements in LMBs have been realized.

High-Safety and High-Energy-Density Lithium Metal Batteries in a Novel Ionic-Liquid Electrolyte.

Rechargeable lithium metal batteries are next generation energy storage devices with high energy density, but face challenges in achieving high energy density, high safety, and long cycle life. Here, lithium metal batteries in a novel nonflammable ionic-liquid (IL) electrolyte composed of 1-ethyl-3-methylimidazolium (EMIm) cations and high-concentration bis(fluorosulfonyl)imide (FSI) anions, with sodium bis(trifluoromethanesulfonyl)imide (NaTFSI) as a key additive are reported. The Na ion participates in the formation of hybrid passivation interphases and contributes to dendrite-free Li deposition and reversible cathode electrochemistry. The electrolyte of low viscosity allows practically useful cathode mass loading up to ≈16 mg cm-2 . Li anodes paired with lithium cobalt oxide (LiCoO2 ) and lithium nickel cobalt manganese oxide (LiNi0.8 Co0.1 Mn0.1 O2 , NCM 811) cathodes exhibit 99.6-99.9% Coulombic efficiencies, high discharge voltages up to 4.4 V, high specific capacity and energy density up to ≈199 mAh g-1 and ≈765 Wh kg-1 respectively, with impressive cycling performances over up to 1200 cycles. Highly stable passivation interphases formed on both electrodes in the novel IL electrolyte are the key to highly reversible lithium metal batteries, especially for Li-NMC 811 full batteries.

Regulating Li-Ion Migration in Solid-State Electrolytes for Li Metal Anodes

Lithium (Li) metal batteries are strongly considered one of the most promising candidates for next-generation rechargeable batteries due to their high theoretical specific capacity and low reduction potential. However, Li metal anodes are suffering from limited cycle life, low cycling efficiency, and severe safety concerns resulting from sharp Li dendrites and electrolyte degradation.The uncontrollable Li dendrite growth caused by the uneven distribution of Li ions is an extremely complicated issue coupled with the transport of anions, cations and electrons, as well as the chemical and electrochemical reactions at the anode-electrolyte interphase. In terms of the ion migration, space-charge theory indicates that the electrolyte is divided into a quasi-neutral region and a space-charge region. The quasi-neutral region approaches the cathode side, at which the ion transfer is governed by diffusion. In contrast, when ions travel close to the anode side, the ion transport is mainly driven by the electric field, leaving a space-charge region that accounts for ramified Li metal growth. Consequently, it is rewarding to design electrolytes that can regulate the ion distribution (including both Li cations and the counter anions) to inhibit Li dendrite growths.Immobilizing anion has been theoretically proved to influence cation distribution, where a portion of immobilized anions (even as small as 10%) contribute to stable Li electrodeposition. Here, we develop an anion-immobilized solid-state composite electrolyte for Li metal anodes. Garnet-type Li6.75La3Zr1.75Ta0.25O12 (LLZTO) ceramic particles are well dispersed in a polymer matrix to synthesize a polyethylene oxide (PEO)–lithium bis(trifluoromethylsulphonyl)imide (LiTFSI)–LLZTO (PLL) solid electrolyte. In contrast to routine electrolytes with mobile anions, the PLL solid electrolyte contributes to effective immobilization of anions for uniform ion distribution and dendrite-free Li deposition. Chemical and mechanical interactions between ceramic particles and the polymer matrix result in reduced PEO crystallinity and pinned TFSI−anions, enabling relatively fast Li+conduction. We further demonstrate the application of this flexible membrane in all–solid-state LiFePO4 (LFP) || Li and LiNi0.5Co0.2Mn0.3O2(NCM) || Li batteries.Moreover, ion migration in batteries can be analogized to the fluid transportation in packed towers in the field of chemical industry. Redistributors are used to intensify the heat and mass transfer processes in a packed tower. Solid-state electrolyte LLZTO, with abundant 3D ion conduction channels, can act as a redistributor to regulate Li-ion distribution. We propose a concept of ion redistributors to eliminate dendrites by redistributing Li ions with LLZTO coated polypropylene (PP) separators in Li metal batteries. The standard deviation of ion concentration beneath the LLZTO composite separator is 13 times less than that beneath the routine PP separator. This approach enables a high specific capacityfor LiFePO4|| Li pouch cells and prolonged cycle life span of 800 hours for Li || Li pouch cells. This strategy is facile and efficient in regulating Li-ion deposition by separator modifications and is a universal method to protect alkali metal anodes in rechargeable batteries.

Realizing Dendrite-Free Lithium Deposition with a Composite Separator.

A dendrite-free Li deposition strategy is developed with a composite separator of MnCO3 coated porous polypropylene. Mn2+ ions are preferentially reduced to form Mn nanoparticles on Li anodes, which helped to reduce the nucleation overpotential and achieve a dendrite-free deposition of Li bulky grains. When MnCO3 contacts the Li metal anode directly, an in situ artificial solid electrolyte interphase passivating layer was created from the reaction of Li metal, MnCO3 and liquid electrolyte. Li metal anodes show significantly improved stability for more than 2000 h of plating/stripping in Li||Li symmetric cells. The homemade ultrathin Li films on Cu foils (Li@Cu), obtained by electrochemical Li deposition with PP/MnCO3 separators, give enhanced cycling stability in LFP||Li@Cu cells. Combined with gel polymer electrolyte, the cycling stability of quasi-solid-state LFP||Li@Cu was further improved. This strategy for dendrite-free deposition via a composite separator provides a low-cost but efficient choice for alkaline metal batteries.

Porous membrane with improved dendrite resistance for high-performance lithium metal-based battery

Lithium metal is one of the most promising anode materials for next-generation power batteries because of its high energy density and low reduction potential. Unfortunately, uncontrolled Li dendrite growth during cycling leads to an unstable interface, a limited cycling life, and a low Coulombic efficiency, further results in severe capacity decay and safety issues. To address these problems, an effective approach is proposed to realize uniform Li nucleation. Herein, we demonstrate a thermally stable polybenzimidazole (PBI) polymer for making porous membranes with a tuneable morphology via a versatile non-solvent treatment method for Lithium-ion battery's (LIBs) application. The final morphology of PBI membranes is controlled by selecting the appropriate non-solvent and an optimized performance could also be obtained. Notably, our functional porous PBI membrane with abundant polar amine functional groups could enable dendrite-free Li deposition, showing stable and low overpotential cycling durability for 400 h at a current density of 1 mA cm−2. With such a membrane, the LiFePO4/Li cell shows superior cycle stability and rate performance, which are higher than those of commercial PE separators. Remarkably, this work offers a simple and facile method to prepare advance porous membranes for lithium-ion batteries with improved dendrite resistance.