Unstable Solid Electrolyte Interphase Research Articles

Synergetic regulation of SEI mechanics and crystallographic orientation for stable lithium metal pouch cells

The advancement of Li-metal batteries is significantly impeded by the presence of unstable solid electrolyte interphase and Li dendrites upon cycling. Herein, we present an innovative approach to address these issues through the synergetic regulation of solid electrolyte interphase mechanics and Li crystallography using yttrium fluoride/polymethyl methacrylate composite layer. Specifically, we demonstrate the in-situ generation of Y-doped lithium metal through the reaction of composite layer with Li metal, which reduces the surface energy of the (200) plane, and tunes the preferential crystallographic orientation to (200) plane from conventional (110) plane during Li plating. These changes effectively passivate Li metal, thereby significantly reducing undesired side reactions between Li and electrolytes by 4 times. Meanwhile, the composite layer with suitable modulus (~1.02 GPa) can enhance mechanical stability and maintain structural stability of SEI. Consequently, a 4.2 Ah pouch cell with high energy density of 468 Wh kg−1 and remarkable capacity stability of 0.08% decay/cycle is demonstrated under harsh condition, such as high-areal-capacity cathode (6 mAh cm−2), lean electrolyte (1.98 g Ah−1), and high current density (3 mA cm−2). Our findings highlight the potential of reactive composite layer as a promising strategy for the development of stable Li-metal batteries.

Thickness Variation of Conductive Polymer Coatings on Si Anodes for the Improved Cycling Stability in Full Pouch Cells.

Si-dominant anodes for Li-ion batteries provide very high gravimetric and volumetric capacity but suffer from low cycling stability due to an unstable solid electrolyte interphase (SEI). In this work, we improved the cycling performance of Si/NCM pouch cells by coating the Si anodes with the conductive polymer poly(3,4-ethylenedioxythiophene) (PEDOT) prior to cell assembly via an electropolymerization process. The thicknesses of the PEDOT coatings could be adjusted by a facile process parameter variation. Glow-discharge optical emission spectroscopy was used to determine the coating thicknesses on the electrodes prior to the cell assembly. During electrochemical testing, improvements were observed closely linked to the PEDOT coating thickness. Specifically, thinner PEDOT coatings exhibited a higher capacity retention and lower internal resistance in the corresponding pouch cells. For the thinnest coatings, the cell lifetime was 18% higher compared to that of uncoated Si anodes. Postmortem analyses via X-ray photoelectron spectroscopy and cross-sectional scanning electron microscopy revealed a better-maintained microstructure and a chemically different SEI for the PEDOT-coated anodes.

Development of Si-Based Anodes for All-Solid-State Li-Ion Batteries

All-solid-state Li-ion batteries (ASSBs) promise higher safety and energy density than conventional liquid electrolyte-based Li-ion batteries (LIBs). Silicon (Si) is considered one of the most promising anode materials due to its high specific capacity (3590 mAh g−1) but suffers from poor cycling performance because of large volumetric effects leading to particle pulverization, unstable solid electrolyte interphase (SEI), and electric disconnection. In ASSBs, additional issues such as poor solid–solid contacts and interfacial side reactions between Si and solid-state electrolytes (SSEs) are also hindering their practical application. This review first outlines the prospects and recent research achievements of Si-based anodes with special focuses on various Si structures and composite materials, then analyzes the issues of electrochemical–mechanical effects, and finally summarizes key factors and promising strategies for further improving Si-based anodes for high-performance ASSBs.

A locally solvent-tethered polymer electrolyte for long-life lithium metal batteries

Solid polymer electrolytes exhibit enhanced Li+ conductivity when plasticized with highly dielectric solvents such as N,N-dimethylformamide (DMF). However, the application of DMF-containing electrolytes in solid-state batteries is hindered by poor cycle life caused by continuous DMF degradation at the anode surface and the resulting unstable solid-electrolyte interphase. Here we report a composite polymer electrolyte with a rationally designed Hofmann-DMF coordination complex to address this issue. DMF is engineered on Hofmann frameworks as tethered ligands to construct a locally DMF-rich interface which promotes Li+ conduction through a ligand-assisted transport mechanism. A high ionic conductivity of 6.5 × 10−4 S cm−1 is achieved at room temperature. We demonstrate that the composite electrolyte effectively reduces the free shuttling and subsequent decomposition of DMF. The locally solvent-tethered electrolyte cycles stably for over 6000 h at 0.1 mA cm−2 in Li | |Li symmetric cell. When paired with sulfurized polyacrylonitrile cathodes, the full cell exhibits a prolonged cycle life of 1000 cycles at 1 C. This work will facilitate the development of practical polymer-based electrolytes with high ionic conductivity and long cycle life.

Stable sodium metal anode enabled by interfacial room‐temperature liquid metal engineering for high‐performance sodium–sulfur batteries with carbonate‐based electrolyte

AbstractSodium (Na) metal is a competitive anode for next‐generation energy storage applications in view of its low cost and high‐energy density. However, the uncontrolled side reactions, unstable solid electrolyte interphase (SEI) and dendrite growth at the electrode/electrolyte interfaces impede the practical application of Na metal as anode. Herein, a heterogeneous Na‐based alloys interfacial protective layer is constructed in situ on the surface of Na foil by self‐diffusion of liquid metal at room temperature, named “HAIP Na.” The interfacial Na‐based alloys layer with good electrolyte wettability and strong sodiophilicity, and assisted in the construction of NaF‐rich SEI. By means of direct visualization and theoretical simulation, we verify that the interfacial Na‐based alloys layer enabling uniform Na+ flux deposition and suppressing the dendrite growth. As a result, in the carbonate‐based electrolyte, the HAIP Na||HAIP Na symmetric cells exhibit a remarkably enhanced cycling life for more than 650 h with a capacity of 1 mAh cm−2 at a current density of 1 mA cm−2. When the HAIP Na anode is paired with sulfurized polyacrylonitrile (SPAN) cathode, the SPAN||HAIP Na full cells demonstrate excellent rate performance and cycling stability.

Binary Solvent Induced Stable Interphase Layer for Ultra-Long Life Sodium Metal Batteries.

Sodium foil, promising for high-energy-density batteries, faces reversibility challenges due to its inherent reactivity and unstable solid electrolyte interphase (SEI) layer. In this study, a stable sodium metal battery (SMB) is achieved by tuning the electrolyte solvation structure through the addition of co-solvent 2-methyl tetrahydrofuran (MTHF) to diglyme (Dig). The introduction of cyclic ether-based MTHF results in increased anion incorporation in the solvation structure, even at lower salt concentrations. Specifically, the anion stabilization capabilities of the environmentally sustainable MTHF co-solvent lead to a contact-ion pair-based solvation structure. Time-of-flight mass spectroscopy analysis reveals that a shift toward an anion-dominated solvation structure promotes the formation of a thin and uniform SEI layer. Consequently, employing a NaPF6-based electrolyte with a Dig:MTHF ratio of 50% (v/v) binary solvent yields an average Coulombic efficiency of 99.72% for 300 cycles in Cu||Na cell cycling. Remarkably, at a C/2 cycling rate, Na||Na symmetric cell cycling demonstrates ultra-long-term stability exceeding 7000 h, and full cells with Na0.44MnO2 as a cathode retain 80% of their capacity after 500 cycles. This study systematically examines solvation structure, SEI layer composition, and electrochemical cycling, emphasizing the significance of MTHF-based binary solvent mixtures for high-performance SMBs.

Three-dimensional faveolate porous N-doped carbon skeleton embodied with nano Bi toward stable less-Na sodium metal batteries

Sodium metal batteries (SMBs) have been widely investigated recently due to the low price of Na metal, satisfactory energy density and similar chemical properties to lithium. However, SMBs also face challenges like low Na utilization, dendrite growth, dead sodium accumulation, unstable solid electrolyte interphase and massive bubble generation. To improve their safety and cycling stability, herein, we fabricate a porous hybrid framework, i.e., fine Bi nanoparticles anchored in porous N-doped carbon matrix (Bi@PNC), as a modified layer upon Cu collector toward stable SMBs. Upon electrochemical activation, the nanoscale Bi-derived Na–Bi alloy with high sodiophilicity reduces the nucleation overpotential of Na, inhibits the formation of Na dendrites, and decreases the loss of Na during cycling. Thanks to these striking merits, the half cells assembled with Na undergo 1600 cycles (3200 h) at 1 mA cm−2, 1 mAh cm−2 with the average Coulombic efficiency of 99.95%. The optimized Bi@PNC based symmetric cells still maintain the overpotential of ∼9.2 mV under 1 mA cm−2 and depth of discharge of 16.7% after cycling for 2420 h. Furthermore, the assembled less-Na full SMBs exhibit superb electrochemical properties. Our strategy here provides meaningful avenue to construct stable less-Na metallic anodes for advanced SMBs.

The Influence of Cathode Degradation Products on the Anode Interface in Lithium-Ion Batteries.

Degradation of cathode materials in lithium-ion batteries results in the presence of transition metal ions in the electrolyte, and these ions are known to play a major role in capacity fade and cell failure. Yet, while it is known that transition metal ions migrate from the metal oxide cathode and deposit on the graphite anode, their specific influence on anode reactions and structures, such as the solid electrolyte interphase (SEI), is still quite poorly understood due to the complexity in studying this interface in operational cells. In this work we combine operando electrochemical atomic force microscopy (EC-AFM), electrochemical quartz crystal microbalance (EQCM), and electrochemical impedance spectroscopy (EIS) measurements to probe the influence of a range of transition metal ions on the morphological, mechanical, chemical, and electrical properties of the SEI. By adding representative concentrations of Ni2+, Mn2+, and Co2+ ions into a commercially relevant battery electrolyte, the impacts of each on the formation and stability of the anode interface layer is revealed; all are shown to pose a threat to battery performance and stability. Mn2+, in particular, is shown to induce a thick, soft, and unstable SEI layer, which is known to cause severe degradation of batteries, while Co2+ and Ni2+ significantly impact interfacial conductivity. When transition metal ions are mixed, SEI degradation is amplified, suggesting a synergistic effect on the cell stability. Hence, by uncovering the roles these cathode degradation products play in operational batteries, we have provided a foundation upon which strategies to mitigate or eliminate these degradation products can be developed.

3D Host Design Strategies Guiding “Bottom–Up” Lithium Deposition: A Review

AbstractLithium metal batteries (LMBs) have the potential to be the next‐generation rechargeable batteries due to the high theoretical specific capacity and the lowest redox potential of lithium metal. However, the practical application of LMBs is hindered by challenges such as the uncontrolled growth of lithium dendrites, unstable solid electrolyte interphase (SEI), and excessive volume change of Li metal. To solve these issues, the design of high‐performance lithium metal anodes (LMAs) with various 3D structures is critical. Targeting at realizing the “bottom–up” Li deposition to fully utilize the 3D architecture, in recent years, strategies such as gradient host materials construction, magnetic field modulation, SEI component design, and so on have attracted intensive attention. This review begins with a fundamental discussion of the Li nucleation and deposition mechanism. The recent advances in the aspects of construction strategies and modification methods that enable the “bottom–up” Li deposition within advanced 3D host materials, with a particular emphasize on their design principles are comprehensively overviewed. Finally, future challenges and perspectives on the design of advanced hosts toward practical LMAs are proposed.

Construction of robust solid-electrolyte interphase via electrode additive for high-performance Sn-based anodes of sodium-ion batteries

Alloy-based Sn anode for sodium-ion batteries has attracted tremendous attention due to its low working voltage, high specific capacity, and good availability. Its application is hindered, however, by inferior cycling stability due to its huge volume changes and unstable solid-electrolyte interphase (SEI) film. Herein, tetraphenylphosphonium bis(trifluoromethanesulfonyl)imide (TPPTFSI) is introduced into the electrode and spontaneously adsorbed on the surfaces of commercial Sn microparticles (μ-Sn) to improve the electrochemical performance of the Sn anode. In the first cycle, the TPP+ component of TPPTFSI decomposes to form an organic component of the SEI film, thereby enhancing its flexibility. Meanwhile, the TFSI− component is converted into an inorganic constituent of the SEI, improving its robustness and ionic conductivity. Therefore, the cycling performance of the μ-Sn is enhanced significantly. The modified electrode, TPPTFSI-Sn, delivers a capacity of 619.7 mAh g−1 after 2000 cycles at 2.0 A g−1, while the control sample can only survive for 30 cycles. Importantly, the full cell also exhibits excellent performance, including rate performance and cycling stability. Its simple operation and remarkable electrochemical performance improvement indicate the promising prospects of this strategy for advanced electrodes in SIBs.

Engineering a lithium silicate-based artificial solid electrolyte interphase for enhanced rechargeable lithium metal batteries

The main motivation for replacing lithium-ion batteries with lithium metal batteries is to achieve a higher energy density by using the metallic lithium anode. One of the major challenges with rechargeable lithium metal batteries is the formation of lithium dendrites and dead lithium during repeated cycling. Another challenge is the formation of the unstable solid electrolyte interphase (SEI) on the surface of the lithium metal electrode, which can reduce battery efficiency and cycle life. In the present work, two different lithium silicates (Li2Si2O5 and Li2SiO3) are successfully synthesized and implemented as an artificial SEI layer via a simple dry coating method. The lithium silicate coating acts as a protective barrier that prevents direct contact between the lithium metal and the electrolyte, which can cause undesirable side reactions and reduce the efficiency and lifetime of the battery. The lithium silicate artificial SEI layer improves the stability of lithium metal batteries by reducing unwanted surface reactions, optimizing ion transport kinetics, and protecting the lithium metal anode from mechanical deformation and unstable SEI formation during extended cycling. This laminated lithium anode structure can be an effective design for the future development of rechargeable lithium metal batteries.

Hybrid Dynamic Covalent Network-Based Protecting Layer for Stable Li-Metal Batteries.

Metallic lithium (Li) is considered as the "Holy Grail" anode material for next-generation energy storage systems due to its extremely high theoretical capacity and low electrochemical potential. Before the commercialization of the Li electrode, dendritic Li growth and the unstable solid electrolyte interphase layer should be conquered. Herein, a hybrid covalent adaptable polymer network (HCAPN) is prepared via the random copolymerization of poly(ethylene glycol) methyl ether methacrylate and -acetoacetoxyethyl methacrylate, followed by chemical cross-linking with polyethylenimine (PEI) and amine-modified silicon dioxide (SiO2). Such a hybrid network, where PEI and amine-modified SiO2 formed a vinylogous urethane-based dynamic covalent bond with the copolymer, respectively, shows improved mechanical properties, solvent resistance, and excellent healability/recyclability. As the protecting layer on the Li electrode, the assembled HCAPN@Li||HCAPN@Li symmetric cell shows a long cycle life of 800 h with low overpotential at a current density of 1 mA cm-2, and superior electrochemical performance can be achieved in the HCAPN@Li||LiFePO4 full cell (capacity retention of 77% over 400 cycles at 1.5 C) and HCAPN@Li||NCM811 cell (capacity retention of 79% after 300 cycles). Surface morphology analysis is also performed for physical insight into their role as protecting layer. This work provides a new perspective for constructing a hybrid dynamic covalent network-based polymer protecting layer for inhibiting Li dendrite growth.

Stoichiometric Ti3C2Tx Coating for Inhibiting Dendrite Growth in Anode‐Free Lithium Metal Batteries

Lithium metal batteries (LMBs) and anode‐free LMBs (AFLMBs) present a solution to the need for batteries with a significantly superior theoretical energy density. However, their adoption is hindered by low Coulombic efficiency (CE) and rapid capacity fading, primarily due to the formation of unstable solid electrolyte interphase (SEI) layer and Li dendrite growth as a result of uneven Li plating. Here, we report on the use of a stoichiometric Ti3C2Tx (S‐Ti3C2Tx) MXene coating on the copper current collector to enhance the cyclic stability of an anode‐free lithium metal battery. The S‐Ti3C2Tx coating provides abundant nucleation sites, thereby lowering the overpotential for Li nucleation, and promoting uniform Li plating. Additionally, the fluorine (−F) termination of S‐Ti3C2Tx participates in the SEI formation, producing a LiF‐rich SEI layer, vital for stabilizing the SEI and improving cycle life. Batteries equipped with S‐Ti3C2Tx@Cu current collectors displayed reduced Li consumption during stable SEI formation, resulting in a significant decrease in capacity loss. AFLMBs with S‐Ti3C2Tx@Cu current collectors achieved a high initial capacity density of 4.2 mAh cm−2, 70.9% capacity retention after 50 cycles, and an average CE of 98.19% in 100 cycles. This innovative application of MXenes in the energy field offers a promising strategy to enhance the performance of AFLMBs and could potentially accelerate their commercial adoption.

Regulating Ion‐Dipole Interactions in Weakly Solvating Electrolyte towards Ultra‐Low Temperature Sodium‐Ion Batteries

AbstractSodium‐ion batteries (SIBs) are recognized as promising energy storage devices. However, they suffer from rapid capacity decay at ultra‐low temperatures due to high Na+ desolvation energy barrier and unstable solid electrolyte interphase (SEI). Herein, a weakly solvating electrolyte (WSE) with decreased ion‐dipole interactions is designed for stable sodium storage in hard carbon (HC) anode at ultra‐low temperatures. 2‐methyltetrahydrofuran with low solvating power is incorporated into tetrahydrofuran to regulate the interactions between Na+ and solvents. The reduced Na+‐dipole interactions facilitate more anionic coordination in the first solvation sheath, which consistently maintains anion‐enhanced solvation structures from room to low temperatures to promote inorganic‐rich SEI formation. These enable WSE with a low freezing point of −83.3 °C and faster Na+ desolvation kinetics. The HC anode thus affords reversible capacities of 243.2 and 205.4 mAh g−1 at 50 mA g−1 at −40 and −60 °C, respectively, and the full cell of HC||Na3V2(PO4)3 yields an extended lifespan over 250 cycles with high capacity retention of ~100 % at −40 °C. This work sheds new lights on the ion‐dipole regulation for ultra‐low temperature SIBs.

Regulating Ion-Dipole Interactions in Weakly Solvating Electrolyte towards Ultra-Low Temperature Sodium-Ion Batteries.

Sodium-ion batteries (SIBs) are recognized as promising energy storage devices. However, they suffer from rapid capacity decay at ultra-low temperatures due to high Na+ desolvation energy barrier and unstable solid electrolyte interphase (SEI). Herein, a weakly solvating electrolyte (WSE) with decreased ion-dipole interactions is designed for stable sodium storage in hard carbon (HC) anode at ultra-low temperatures. 2-methyltetrahydrofuran with low solvating power is incorporated into tetrahydrofuran to regulate the interactions between Na+ and solvents. The reduced Na+-dipole interactions facilitate more anionic coordination in the first solvation sheath, which consistently maintains anion-enhanced solvation structures from room to low temperatures to promote inorganic-rich SEI formation. These enable WSE with a low freezing point of -83.3 °C and faster Na+ desolvation kinetics. The HC anode thus affords reversible capacities of 243.2 and 205.4 mAh g-1 at 50 mA g-1 at -40 and -60 °C, respectively, and the full cell of HC||Na3V2(PO4)3 yields an extended lifespan over 250 cycles with high capacity retention of ~100 % at -40 °C. This work sheds new lights on the ion-dipole regulation for ultra-low temperature SIBs.

Enabling Uniform and Stable Lithium-Ion Diffusion at the Ultrathin Artificial Solid-Electrolyte Interface in Siloxene Anodes.

Constructing a stable and robust solid electrolyte interphase (SEI) has a decisive influence on the charge/discharge kinetics of lithium-ion batteries (LIBs), especially for silicon-based anodes which generate repeated destruction and regeneration of unstable SEI films. Herein, a facile way is proposed to fabricate an artificial SEI layer composed of lithiophilic chitosan on the surface of two-dimensional siloxene, which has aroused wide attention as an advanced anode for LIBs due to its special characteristics. The optimized chitosan-modified siloxene anode exhibits an excellent reversible cyclic stability of about 672.6 mAh g-1 at a current density of 1000mA g-1 after 200 cycles and 139.9 mAh g-1 at 6000mA g-1 for 1200 cycles. Further investigation shows that a stable and LiF-rich SEI film is formed and can effectively adhere to the surface during cycling, redistribute lithium-ion flux, and enable a relatively homogenous lithium-ion diffusion. This work provides constructive guidance for interface engineering strategy of nano-structured silicon anodes.

Low-Temperature and Fast-Charge Sodium Metal Batteries.

Low-temperature operation of sodium metal batteries (SMBs) at the high rate faces challenges of unstable solid electrolyte interphase (SEI), Na dendrite growth, and sluggish Na+ transfer kinetics, causing a largely capacity curtailment. Herein, low-temperature and fast-charge SMBs are successfully constructed by synergetic design of the electrolyte and electrode. The optimized weak-solvation dual-salt electrolyte enables high Na plating/stripping reversibility and the formation of NaF-rich SEI layer to stabilize sodium metal. Moreover, an integrated copper sulfide electrode is in situ fabricated by directly chemical sulfuration of copper current collector with micro-sized sulfur particles, which significantly improves the electronic conductivity and Na+ diffusion, knocking down the kinetic barriers. Consequently, this SMB achieves the reversible capacity of 202.8mAhg-1 at -20°C and 1C (1C = 558mAg-1 ). Even at -40°C, a high capacity of 230.0mAhg-1 can still be delivered at 0.2C. This study is encouraging for further exploration of cryogenic alkali metal batteries, and enriches the electrode material for low-temperature energy storage.

Enhancing low-temperature electrolyte performance through intermittent discharge for improved LiODFB additive film formation

The challenge of improving low-temperature performance in lithium-ion batteries (LIBs) is attributed to the formation of an unstable solid electrolyte interphase (SEI) film. Lithium difluoro(oxalate)borate (LiODFB) has demonstrated potential in enhancing capacity retention and reducing impedance at low temperatures by establishing a high ion conductivity and stable SEI layer. Previous research indicates that the BOF2− anion, a soluble product of film formation additive of LiODFB hinder salt decomposition by aggregating on the electrode surface. This study presents a strategy to intensify the film formation process of LiODFB additives by introducing an optimal standing time during intermittent discharge processes. Three specific stages of soluble product diffusion are discussed. Diffusion starts from the outer layer of adsorption composed of soluble substances, gradually extends to the inner layer of adsorption, and finally establishes a new connection with the electrode. A brief standing time proves insufficient for inner adsorption layer diffusion, while excessively extended standing time fails to accelerate LiODFB decomposition. A standing time of 2300 s is selected to promote a stable SEI layer. This strategy elevates the capacity retention rate of cells at –20 °C from 66.59 % to 84.44 %. The study offers a method to address battery performance degradation in low-temperature conditions.

Multiple protective layers for suppressing Li dendrite growth and improving the cycle life of anode-free lithium metal batteries

Anode-free lithium metal batteries (AFLMBs) have sparked considerable attention in recent years because of their potential for high energy density; however, they suffer from severe Li dendrite growth and unstable solid electrolyte interphase (SEI), which typically result in rapid capacity decay. Herein, we demonstrate a long-life anode-free pouch cell by designing a dual-coating protective layer (Cu-Sn@SFPH) electrode with Sn-coated Cu (denoted as Cu-Sn) as the bottom layer and SrF2 nanoparticles strengthened by poly (vinylidene fluoride)-co-hexafluoropropylene (PVDF-HFP) as the top layer. The in-situ formed LiF-rich SEI enables fast Li+ transfer, while the lithiophilic Li-Sn and Li-Sr alloy layers serve as nucleation seeds for uniform Li deposition. The dual-coated Cu electrode in the Cu-Sn@SFPH||Li cell exhibits remarkable cycling stability for more than 3,200 h at a capacity of 2 mAh cm−2. The NCM111||Cu-Sn@SFPH pouch cell demonstrates outstanding performance with a capacity retention of 72.1 % and an average Coulombic efficiency (CE) of 99.9 % for 120 cycles. Under practical conditions, with NCM cathodes and a lean electrolyte volume, this design strategy opens a new approach to AFLMBs.

Orderly Arranged Dipoles Regulate Anion-Derived Solid-Electrolyte Interphase for Stable Lithium Metal Chemistry.

Lithium (Li) metal batteries are considered the most promising high-energy-density electrochemical energy storage devices of the next generation. However, the unstable solid-electrolyte interphase (SEI) derived from electrolytes usually leads to high impedance, Li dendrites growth, and poor cyclability. Herein, the ferroelectric BaTiO3 with orderly arranged dipoles (BTOV) is integrated into the polypropylene separator as a functional layer. Detailed characterizations and theoretical calculations indicate that surface oxygen vacancies drive the phase transition of BaTiO3 materials and promote the ordered arrangement of dipoles. The strong dipole moments in BTOV can adsorb TFSI- and NO3 - anions selectively and promote their preferential reduction to form a SEI film enriched with inorganic LiF and LiNxOy species, thus facilitating the rapid transfer of Li+ and restraining the growth of Li dendrites. As a result, the Li-Li cell with the BTOV functional layer exhibits enhanced Li plating/stripping cycling with an ultra-long life of over 7000h at 0.5mAcm-2/1.0mAhcm-2. The LiFePO4 || Li (50µm) full cells display excellent cycling performance exceeding 1760 cycles and superior rate performance. This work provides a new perspective for regulating SEI chemistry by introducing ordered dipoles to control the distribution and reaction of anions.