Integrated lithium metal anode protected by composite solid electrolyte film enables stable quasi-solid-state lithium metal batteries

Lithium (Li) metal, possessing an extremely high theoretical specific capacity (3860 mAh/g) and the most negative electrode potential (−3.040 V vs. standard hydrogen electrode), is one the most favorable anode materials for future high-energy-density batteries. However, the poor cyclability and safety issues induced by extremely unstable interfaces of traditional liquid Li metal batteries have limited their practical applications. Herein, a quasi-solid battery is constructed to offer superior interfacial stability as well as excellent interfacial contact by the incorporation of Li@composite solid electrolyte integrated electrode and a limited amount of liquid electrolyte (7.5 μL/cm²). By combining the inorganic garnet Al-doped Li_6.75La₃Zr_1.75Ta_0.25O₁₂ (LLZO) with high mechanical strength and ionic conductivity and the organic ethylene-vinyl acetate copolymer (EVA) with good flexibility, the composite solid electrolyte film could provide sufficient ion channels, sustained interfacial contact and good mechanical stability at the anode side, which significantly alleviates the thermodynamic corrosion and safety problems induced by liquid electrolytes. This innovative and facile quasi-solid strategy is aimed to promote the intrinsic safety and stability of working Li metal anode, shedding light on the development of next-generation high-performance Li metal batteries.     

Diethyl phenylphosphonite contributing to solid electrolyte interphase and cathode electrolyte interphase for lithium metal batteries

Lithium metal batteries have obtained increasing interest due to their high specific capacity.Nonetheless,the growth of lithium dendrites brings safety risks to...     

Synthesizing an inorganic-rich solid electrolyte interphase by tailoring solvent chemistry in carbonate electrolyte for enabling high-voltage lithium metal batteries

High-voltage(>4.0 V) lithium metal battery(LBM) is considered to be one of the most promising candidates for next-generation high-energy batteries. However, the commercial carbonate electrolyte delivers a poor compatibility with Li metal anode, and its organic dominated solid electrolyte interphase(SEI) shows a low interfacial energy and a slow Li⁺diffusion ability. In this work, an inorganic LiF-Li₃N rich SEI is designed to enable high-voltage LBM by introducing nano-cu...     

Unique double-layer solid electrolyte interphase formed with fluorinated ether-based electrolytes for high-voltage lithium metal batteries

Li metal batteries using high-voltage layered oxides cathodes are of particular interest due to their high energy density. However, they suffer from short lifespan and extreme safety concerns, which are attributed to the degradation of layered oxides and the decomposition of electrolyte at high voltage, as well as the high reactivity of metallic Li. The key is the development of stable electrolytes against both highvoltage cathodes and Li with the formation of robust interphase films on the surf...     

Polar interaction of polymer host–solvent enables stable solid electrolyte interphase in composite lithium metal anodes

The lithium(Li) metal anode is an integral component in an emerging high-energy-density rechargeable battery.A composite Li anode with a three-dimensional(3 D) host exhibits unique advantages in suppressing Li dendrites and maintaining dimensional stability.However,the fundamental understanding and regulation of solid electrolyte interphase(SEI),which directly dictates the behavior of Li plating/stripping,are rarely researched in composite Li metal anodes.Herein,the interaction between a polar p...     

Heterogeneous electrolyte membranes enabling double-side stable interfaces for solid lithium batteries

The solid polymer electrolyte(SPE)is one of the most promising candidates for building solid lithium bat-teries with high energy density and safety due to its a...     

Electrolyte and interphase engineering through solvation structure regulation for stable lithium metal batteries

Lithium metal batteries (LMBs) are considered to be one of the most promising high-energy-density battery systems. However, their practical application in carbonate electrolytes is hampered by lithium dendrite growth, resulting in short cycle life. Herein, an electrolyte regulation strategy is developed to improve the cyclability of LMBs in carbonate electrolytes by introducing LiNO₃ using trimethyl phosphate with a slightly higher donor number compared to NO₃⁻ as a solubilizer. This not only allows the formaion of Li⁺-coordinated NO₃⁻ but also achieves the regulation of electrolyte solvation structures, leading to the formation of robust and ion-conductive solid-electrolyte interphase films with inorganic-rich inner and organic-rich outer layers on the Li metal anodes. As a result, high Coulombic efficiency of 99.1% and stable plating/stripping cycling of Li metal anode in Li||Cu cells were realized. Furthermore, excellent performance was also demonstrated in Li||LiNi_0.83Co_0.11Mn_0.06O₂ (NCM83) full cells and Cu||NCM83 anode-free cells using high mass-loading cathodes. This work provides a simple interphase engineering strategy through regulating the electrolyte solvation structures for high-energy-density LMBs.     

Stable lithium metal anode enabled by a robust artificial fluorinated hybrid interphase

One of the key challenges for achieving stable lithium(Li) metal anode is the construction of the rational solid electrolyte interphase(SEI),but its realization still faces enormous challenges.In this work,a robust artificial fluorinated hybrid interphase consisting of lithium-bismuth(Li₃Bi) alloy and lithium-fluoride(LiF) was designed to regulate Li deposition without Li dendrite growth.The obtained hybrid interphase showed the high Li⁺ diffusion rate(3.5 × 10^-4...     

In situ construction of a stable composite solid electrolyte interphase for dendrite-free Zn batteries

Building a stable solid electrolyte interphase(SEI) has been regarded to be highly effective for mitigating the dendrite growth and parasitic side reactions of Zn anodes. Herein, a robust inorganic composite SEI layer is in situ constructed by introducing an organic cysteine additive to achieve long lifetime Zn metal batteries. The chemisorbed cysteine derivatives are electrochemically reduced to trigger a local alkaline environment for generating a gradient layered zinc hydroxide based multicom...     

A review on the failure and regulation of solid electrolyte interphase in lithium batteries

Solid electrolyte interphase (SEI) has been widely recognized as the most important and the least understood component in lithium batteries.Considering the intr...     

Electrode-compatible fluorine-free multifunctional additive regulating solid electrolyte interphase and solvation structure for high-performance lithium-ion batteries

The rapid development and widespread application of lithium-ion batteries(LIBs) have increased demand for high-safety and high-performance LIBs. Accordingly, various additives have been used in commercial liquid electrolytes to severally adjust the solvation structure of lithium ions, control the components of solid electrolyte interphase, or reduce flammability. While it is highly desirable to develop low-cost multifunctional electrolyte additives integrally that address both safety and perform...     

Polyaniline encapsulated silicon nanocomposite as high-performance anode materials for lithium ion batteries

Polyaniline encapsulated silicon (Si/PANI) nanocomposite as anode materials for high-capacity lithium ion batteries has been prepared by an in situ chemical polymerization of aniline monomer in the suspension of Si nanoparticles. The obtained Si/PANI nanocomposite demonstrates a reversible specific capacity of 840 mAh g^?1 after 100 cycles at a rate of 100 mA g^?1 and excellent cycling stability. The enhanced electrochemical performance can be due to that the polyaniline (PANI) matrix offers a continuous electrically conductive network as well as enhances the compatibility of electrode materials and electrolyte as a result of suppressing volume stress of Si during cycles and preventing the agglomeration of Si nanoparticles.     

In-situ nanoscale insights into the evolution of solid electrolyte interphase shells: revealing interfacial degradation in lithium metal batteries

The solid electrolyte interphase(SEI) has caught considerable attention as a pivotal factor affecting lithium(Li) metal battery performances. However, the understanding of the interfacial evolution and properties of the on-site formed SEI shells on Li deposits during cycling is still at a preliminary stage. Here, we provide a straightforward visualized evidence of SEI shells' evolution during Li deposition/stripping to reveal anode degradation via in-situ atomic force microscopy(AFM). Nucleation and growth of quasi-spherical Li particles are observed on a Cu substrate, followed by Li stripping and collapse of SEI shells. In the subsequent cycling, new Li deposits tend to nucleate at pristine sites with fresh SEI shells forming on Li. The previously collapsed SEI shells accumulate to increase interface impedance, eventually leading to capacity degradation. Revealing the electrochemical processes and interfacial degradation at the nanoscale will enrich fundamental comprehension and further guide improvement strategies of Li metal anodes.     

Ag-modified hydrogen titanate nanowire arrays for stable lithium metal anode in a carbonate-based electrolyte

In the investigation of the next-generation battery anode,Li metal has attracted increasing attention owing to its ultrahigh specific capacity and low reduction potential.However,its low columbic efficiency,limited cycling life,and serious safety hazards have hindered the practical application of rechargeable Li metal batteries.Although several strategies have been proposed to enhance the electrochemical performance of Li metal anodes,most are centered around ether-based electrolytes,which are volatile and do not provide a sufficiently large voltage window.Therefore,we aimed to attain stable Li deposition/stripping in a commercial carbonate-based electrolyte.Herein,we have successfully synthesized hydrogen titanate(HTO)nanowire arrays decorated with homogenous Ag nanoparticles(NPs)(Ag@HTO)via simple hydrothermal and silver mirror reactions.The 3 D cross-linked array structure with Ag NPs provides preferable nucleation sites for uniform Li deposition,and most importantly,when assembled with the commercial LiNi_0.5Co0.2Mn_0.3O₂ cathode material,the Ag@HTO could maintain a capacity retention ratio of 81.2% at 1 C after 200 cycles,however the pristine Ti foil failed to do so after only 60 cycles.Our research therefore reveals a new way of designing current collectors paired with commercial high voltage cathodes that can create high energy density Li metal batteries.     

Investigation of polysulfone film on high-performance anode with stabilized electrolyte/electrode interface for lithium batteries

Lithium metal has been considered to be the most promising anode material for the new generation of energy-storage system.However,challenges still stand in protecting lithium metal from spontaneous reactions with electrolytes and preventing the dendritic propagation,both of which would lead to undesirable decrease in Coulombic efficiency.Polysulfone(PSf)membrane with high rigidity and free-volume cavities of approximately 0.3 nm was employed to provide a stable interface on the surface of anodic electrode.The isotropic channels were constructed by the interconnected and uniformly distributed free volumes in the polymer matrix,and were expected to be swelled by solvent molecules and anions of lithium salt and to allow Li~+ions to pass through onto the electrode surface.As a result,dendrite-free morphology of deposited lithium was observed.The stabilized interface arose from the PSf film was verified by the promoted performances of Cu|Li cells and steady voltage polarization of Li|Li cells.The full cell with PSf coated anode exhibited excellent cyclability(85% capacity retention rate over 400 cycles at 1C)and an outstanding rate capability(117 m Ah g~(-1) at 5C).The beneficial performances were further verified by the EIS results.This work provides a new strategic idea to settle the dendritic problems of Li metal anodes.     

Hierarchically porous Cu current collector with lithiophilic CuxO interphase towards high-performance lithium metal batteries

Lithium metal is one of the most promising anode materials for next-generation electrochemical energy storage due to low electrochemical potential and high spec...     

Towards high-performance lithium metal anodes via the modification of solid electrolyte interphases

Li metal has been regarded as one of the most promising anodes for high-energy-density storage systems due to its high theoretical capacity and lowest electrochemical potential.Unfortunately,an unstable and non-uniform solid electrolyte interphase(SEI)deriving from the spontaneous reaction between Li metal anode and electrolyte causes uneven Li deposition,resulting in the growth of Li dendrites and low Coulombic efficiency,which have greatly hindered the practical application of Li metal batteries.Thus,the construction of a stable SEI is an effective approach to suppress the growth of Li dendrites and enhance the electrochemical performances of Li metal anode.In this review,we firstly introduce the formation process of inferior SEI of Li metal anode and the corresponding challenges caused by the unstable SEI.Next,recent progresses to modify SEI layer through the regulation of electrolyte compositions and exsitu protective coating are summarized.Finally,the remained issues,challenges,and perspectives are also proposed on the basis of current research status and progress.     

Co3O4@graphene composites as anode materials for high-performance lithium ion batteries

This paper reports on the synthesis of Co(3)O(4)@graphene composites (CGC) and their applications as anode materials in lithium ion batteries (LIBs). Through a chemical deposition method, Co(3)O(4) nanoparticles (NPs) with sizes in the range of 10-30 nm were homogeneously dispersed onto graphene sheets. Due to their high electrical conductivity, the graphene sheets in the CGC improved the electrical conductivity and the structure stability of CGC. CGC displayed a superior performance in LIBs with a large reversible capacity value of 941 mA hg(-1) in the initial cycle with a large current density and an excellent cyclic performance of 740 mA hg(-1) after 60 cycles, corresponding to 88.3% of the theoretical value of CGC, owing to the interactions between graphene sheets and Co(3)O(4) NPs anchored on the graphene sheets. This synthesis approach may find its application in the design and synthesis of novel electrode materials used in LIBs.     

Moderately concentrated electrolyte enabling high-performance lithium metal batteries with a wide working temperature range

The electrolyte integrated with lithium metal anodes is subjected to the issues of interfacial compatibility and stability, which strongly influence the performances of high-energy lithium metal batteries. Here, we report a new electrolyte recipe viz. a moderately concentrated electrolyte comprising of 2.4 M lithium bis(fluorosulfonyl)imide(LiFSI) in a cosolvent mixture of fluorinated ethylene carbonate(FEC) and dimethyl carbonate(DMC) with relatively high ion conductivity. Owing to the preferen...     

Anchoring polysulfide with artificial solid electrolyte interphase for dendrite-free and low N/P ratio Li-S batteries

Lithium sulfur batteries are regarded as a promising candidate for high-energy-density energy storage devices. However, the lithium metal anode in lithium-sulfur batteries encounters the problem of lithium dendrites and lithium metal consumption caused by polysulfide corrosion. Herein we design a dualfunction PMMA/PPC/LiNO₃ composite as an artificial solid electrolyte interphase(PMCN-SEI) to protect Li metal anode. This SEI offers multiple sites of C=O for polysulfide anchoring to con...