Stable Solid Electrolyte Interface Research Articles

Co-solvent electrolyte-induced zinc anode surface reconstruction for high performance zinc ion batteries

The progress of rechargeable zinc (Zn) ion batteries (RZBs) has been significantly impeded by the occurrence of side reactions and dendritic issues on Zn anodes, which are attributed to the intricate reaction kinetics observed in aqueous electrolytes. Herein, we propose a co-solvent electrolyte comprising a combination of N, N-dimethylformamide (DMF) and Dimethyl sulfoxide (DMSO). This electrolyte reconstructs the surface of the Zn anode and generates a dense and robust solid electrolyte interface (SEI), which promotes uniform Zn2+ deposition and enhances Zn2+ transport kinetics. The DFT further shows that the electrolyte has a unique solvated structure which enables uniform Zn2+ deposition and the creation of stable SEI. By utilizing these advantages, the co-solvent electrolyte is capable of enduring uninterrupted cycling for more than 4000 h at a current density of 1 mA cm−2, and for over 2000 h at a current density of 5 mA cm−2. Furthermore, the Zn||NH4V4O10 full cell demonstrated exceptional electrochemical performance with regard to charge/discharge capacity and cycle stability. This study showcases the effectiveness of non-aqueous electrolytes, which will enable the progress of secure and high-capacity RZBs.

Vertically Fluorinated Graphene Encapsulated SiOx Anode for Enhanced Li+ Transport and Interfacial Stability in High-Energy-Density Lithium Batteries.

Achieving high energy density has always been the goal of lithium-ion batteries (LIBs). SiOx has emerged as a compelling candidate for use as a negative electrode material due to its remarkable capacity. However, the huge volume expansion and the unstable electrode interface during (de)lithiation, hinder its further development. Herein, we report a facile strategy for the synthesis of surface fluorinated SiOx (SiOx@vG-F), and investigate their influences on battery performance. Systematic experiments investigations indicate that the reaction between Li+ and fluorine groups promotes the in situ formation of stable LiF-rich solid electrolyte interface (SEI) on the surface of SiOx@vG-F anode, which effectively suppresses the pulverization of microsized SiOx particles during the charge and discharge cycle. As a result, the SiOx@vG-F enabled a higher capacity retention of 86.4 % over 200 cycles at 1.0 C in the SiOx@vG-F||LiNi0.8Co0.1Mn0.1O2 full cell. This approach will provide insights for the advancement of alternative electrode materials in diverse energy conversion and storage systems.

Unraveling chemical origins of dendrite formation in zinc-ion batteries via in situ/operando X-ray spectroscopy and imaging

To prevent zinc (Zn) dendrite formation and improve electrochemical stability, it is essential to understand Zn dendrite growth, particularly in terms of morphology and relation with the solid electrolyte interface (SEI) film. In this study, we employ in-situ scanning transmission X-ray microscopy (STXM) and spectro-ptychography to monitor the morphology evolution of Zn dendrites and to identify their chemical composition and distribution on the Zn surface during the stripping/plating progress. Our findings reveal that in 50 mM ZnSO4, the initiation of moss/whisker dendrites is chemically controlled, while their continued growth over extended cycles is kinetically governed. The presence of a dense and stable SEI film is critical for inhibiting the formation and growth of Zn dendrites. By adding 50 mM lithium chloride (LiCl) as an electrolyte additive, we successfully construct a dense and stable SEI film composed of Li2S2O7 and Li2CO3, which significantly improves cycling performance. Moreover, the symmetric cell achieves a prolonged cycle life of up to 3900 h with the incorporation of 5% 12-crown-4 additives. This work offers a strategy for in-situ observation and analysis of Zn dendrite formation mechanisms and provides an effective approach for designing high-performance Zn-ion batteries.

Realizing High-Flux Li+ conduction and stable solid electrolyte interface by Iodine- and Amino-Functionalized MOFs doping in Solid-State electrolytes

Realizing High-Flux Li+ conduction and stable solid electrolyte interface by Iodine- and Amino-Functionalized MOFs doping in Solid-State electrolytes

Biological small molecule interface-modification fostering resilient interfacial chemistry for silicon-based anodes

Silicon-based materials, particularly at the microscale, are prone to rapid capacity fade due to substantial volume fluctuations during the charge-discharge cycles, significantly impeding their commercial viability. Constructing a stable solid electrolyte interface (SEI) is an effective means to improve the performances of silicon-based anodes. Here small biomolecules, tryptophan (Trp) and phytic acid (PA), are introduced as interface modifiers to optimize the interfacial chemistry of micron-silicon anodes. By engaging in the SEI formation process, these small biomolecules effectively regulate the chemical composition and mechanical properties of the formed SEI, fostering a more cohesive and durable interface. The simultaneous addition of PA and Trp has been observed to yield a synergistic effect, creating a tightly bonded and resilient SEI that confers markedly improved battery performances upon the co-modified micron silicon anodes. Density functional theory calculations reveal charge interactions between these small biomolecules and silicon particles, facilitating effective adsorption onto the silicon surface. Simultaneous adsorption of Trp and PA on silicon surface can significantly enhance adsorption strength, providing a compelling explanation for the observed synergistic effect of Trp and PA co-modification.

Hydrophobic Interface Engineering for Highly Reversible and Stable Zn Anodes

AbstractRechargeable aqueous zinc batteries (AZIBs) with merits of high safety and high theoretical capacity are regarded as next‐generation energy storage devices. However, their practical application is hindered by the instable Zn anodes associated with the dendrite growth, parasite corrosion and side reactions. Developing a stable solid electrolyte interface is crucial for improving the cycling stability of Zn anodes. Herein, a hydrophobic interface is constructed on Zn anode through a simple heptafluorobutyrate acid etching route. The hydrophobic interface containing organic C─F, O─C═O and inorganic Zn─F bonds effectively address the issues of dendrites growth and parasitic reactions. Consequently, symmetric cells with acid‐treated Zn‐HA anodes achieve a prolonged lifespan of over 2000 h at 4.0 mA cm−2 and 1100 h at 10.0 mA cm−2. When paired with MnO2 cathode, the full cells deliver lower overpotential and outstanding cycling stability. This strategy provides a simple and feasible method to construct stable Zn anode for achieving high performance AZIBs.

In Situ Fabrication of Solvent-Free Solid Polymer Electrolytes for Wide-Temperature All-Solid-State Lithium Metal Batteries.

All-solid-state lithium metal batteries (ASSLMBs) have been regarded as promising candidates to settle the safety issues of liquid electrolytes for rechargeable lithium batteries. However, the currently reported gel polymer electrolytes still have flammable liquid solvents, thus leading to the potential safety hazard. Here, solvent-free deep eutectic solid polymer electrolytes (SPEs) are designed and fabricated via an in situ polymerization, which are composed of a poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP) electrospun membrane, succinonitrile (SN), poly(ethylene glycol) diacrylate (PEGDA200, Mn = 200 g mol-1), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), and lithium difluoro(oxalato)borate (LiDFOB). The deep eutectic solvent (DES) with SN/LiTFSI provides a superior room-temperature ionic conductivity, while the PEGDA200 precursor acts as cross-linking network to form SPEs under thermal initiation for free radical polymerization, and LiDFOB can form a stable solid electrolyte interface (SEI) layer. The PVDF-HFP electrospun membrane with a three-dimensional nanofibrous network structure for SN/PEGDA200/LiTFSI/LiDFOB SPEs exhibits a wide electrochemical stability window, high lithium-ion transference number, and good compatibility with the lithium metal anode. Furthermore, the obtained SPEs assembled with Li//LiMn0.6Fe0.4PO4, Li//LiFePO4, and Li//LiNi0.8Co0.1Mn0.1O2 asymmetric cells show excellent cycling performance and rate capability at a wide temperature. This strategy provides a promising path in designing high-energy-density ASSLMBs for practical application.

Engineering Moderately Lithiophilic Paper-Based Current Collectors with Variable Solid Electrolyte Interface Films for Anode-Free Lithium Batteries.

Compared to traditional lithium metal batteries, anode-free lithium metal batteries use bare current collectors as an anode instead of Li metal, making them highly promising for mass production and achieving high-energy density. The current collector, as the sole component of the anode, is crucial in lithium deposition-stripping behavior and greatly impacts the rate of Li depletion from the cathode. In this study, to investigate the lithiophilicity effect of the current collector on the solid electrolyte interface (SEI) film construction and cycling performance of anode-free lithium batteries, various lightweight paper-based current collectors were prepared by electroless plating Cu and lipophilic Ag on low-dust paper (LDP). The areal densities of the as-prepared LDP@Cu, LDP@Cu-Ag, and LDP@Ag were approximately 0.33 mg cm-2. The use of lipophilic Ag-coated collectors with varying loadings allowed for the regulation of lipophilicity. The impacts of these collectors on the distribution of SEI components and Li depletion rate in common electrolytes were investigated. The findings suggest that higher loadings of lipophilic materials, such as Ag, on the current collector increase its lipophilicity but also lead to significant Li depletion during the cycling process in full-cell anode-free Li metal batteries. Thus, moderately lithiophilic current collectors, such as LDP@Cu-Ag, show more potential for Li deposition and striping and stable SEI with a low speed of Li depletion.

Introducing nanodiamond-modified electrolyte to realize high capacity and rate performance of sodium ion batteries

The solid electrolyte interface (SEI) acts as a channel for sodium ions from electrolyte to anode, its structure and chemical properties are crucial to the Coulombic efficiency, cycling stability, and even safety of rechargeable batteries. In this work, using bio-carbon as an anode, and nanodiamond (ND) as electrolyte additive, the relation between ND and SEI properties and sodium storage performance is explored. It is found that ND is transferred to the surface of bio-carbon anode and induces the formation of stable and inorganic-rich SEI (such as NaF and Na2O). Besides, the introduction of ND significantly increases the ionic conductivity. The sodium-ion batteries with ND-electrolyte exhibit a superior reversible capacity of 340 mA g−1 after 400 cycles at 0.5 A g−1, long-term cycling stability (183 mA g−1 over 1000 cycles at 5 A g−1), and remarkable rate performance (157 mA h g−1 at 10 A g−1), which is attributed to the fact that the presence of ND could provide additional storage sites and improve the stability of SEI. This study provides valuable guidance for improving the electrochemical performance of electrode materials by regulating the SEI in the optimal electrolyte.

In-situ construction of solid electrolyte interphase for stable zinc anode via synergy of electrochemical reduction and chemical precipitation

Aqueous zinc ion batteries (ZIBs) feature high theoretical capacity, low cost, and high safety, but they suffer from moderate reversibility arising from electrolyte decomposition, Zn corrosion/passivation, and dendrite growth. To address this issue, an effective strategy is to construct a functional solid electrolyte interface (SEI) in situ. However, this is substantially challenging owing to the severe hydrogen evolution reaction (HER) and a lack of substances that can be decomposed to form SEI in the aqueous electrolytes. Herein, we propose the fabrication of a stable SEI in situ via a synergistic electrochemical reduction-chemical precipitation approach. By chemically capturing the hydroxide ions (OH−) from HER, fatty acid methyl ester ethoxylate (FMEE), as an aqueous electrolyte additive, undergoes ester group hydrolysis following by a combination with Zn2+ to form insoluble fatty acid-zinc, enabling intelligent growth of a SEI on the Zn anode surface. As a result, the enhanced Zn anode exhibits a prolonged cycling life of up to 2700 h at 1 mA/cm2 and 1 mAh/cm2. The Zn-V2O5 full cell with the designed electrolyte demonstrates excellent rate capability and significantly improved cycling stability. This study presents a simple and practical strategy for in-situ formation of SEI in aqueous electrolytes, advancing the development of high-performance aqueous batteries.

Systematic Investigations of Surface Oxygen Functional Groups on Spherical Hard Carbon for Sodium-Ion Batteries

The surface activity of hard carbons and its effect on the formation of a stable solid electrolyte interface (SEI) in sodium ion batteries has gained significant interest in the scientific community over the last years. The surface of hard carbons thus plays a pivotal role within the cell, as it constitutes the interface between the bulk material and the electrolyte. Following pyrolysis of the carbon-rich precursor at high temperatures, various oxygen functional groups (OFGs) and defects, such as five- or seven-membered rings, are present on the surface of the resulting hard carbons. The influence of OFGs on the surface is however controversially discussed. On the one hand, irreversible reactions of sodium ions with OFGs lower the initial coulombic efficiency (ICE), which leads to a decreased energy density. On the other hand, OFGs may also serve as nucleation sites for the SEI leading to a more conductive interfacial phase for sodium ions. Although many approaches of additional oxygen functionalization on the surface of hard carbons have already been reported, they mostly employ harsh reaction conditions disregarding the morphological impact on the carbon surface.In our studies, oxo-functionalized polycyclic aromatic hydrocarbons (PAHs) are adsorbed on the surface to serve as model OFGs on surface oxygen deficient hard carbons. The versatility of functionalized pyrenes in combination with nondestructive adsorption enables independent investigations on the oxygen functionalization of the hard carbon surface. In the first step, native surface oxygen groups are cleaved from the pristine hard carbon through a high-temperature post-treatment in hydrogen atmosphere. Afterwards, selective re-introduction of surface OFGs is achieved through adsorption of oxo-functionalized pyrene derivatives such as 1-hydroxypyrene or 1-pyrenecarboxylic acid to simulate hydroxy or carboxylic surface functionalities. Additionally, various spatially configurations of surface OFGs can be mimicked by elongating the distance between the oxygen functionality and the pyrene backbone through a short alkyl chain (e.g. 1-pyrenebutyric acid).Our systematic approach of selectively re-introducing surface OFGs allows the discrimination between different surface OFGs and their influence on the SEI. The surface of our modified hard carbons is characterized by X-Ray photoelectron spectroscopy (XPS) and Raman spectroscopy to evaluate the oxygen content and determine the defect concentration. The electrochemical performance is assessed by rate performance tests and cyclic voltammetry in three-electrode half-cells with sodium metal as counter and reference electrode. Initial findings validate the correlation between surface oxygen functionalization determined by XPS and the electrochemical formation potential of the SEI during the first cycle. After high-temperature treatment in a hydrogen atmosphere, the surface oxygen content decreases from ~5% to 2%, leading to a significant lowering of the plateau capacity. Simultaneously, the ICE decreases from 79% to 55%. Cyclic voltammetry of deoxygenated hard carbon reveals that the SEI formation potential is shifted from ~1.0 V vs. Na towards lower potentials of ~0.3 V vs. Na indicating that different decomposition products are formed. Furthermore, rate performance is substantially deteriorated by the development of a modified SEI. Ex-situ XPS of cycled electrodes and electrochemical impedance spectroscopy are used to identify differences in the SEI composition and link them to the electrochemical performance of our spherical hard carbons.Figure: 1-Pyrenebutyric acid adsorbed on the surface of hard carbon highlighting the different possible spatially orientations of the oxygen functional group. Figure 1

Improved Silicon/Graphite Composite Anode for High-Energy Li-Ion Battery

High-specific capacity of Silicon (~ reaching up to 3600 mAh/g corresponds to Li15Si4) and relatively higher lithiation potential (~0.4V Vs Li+; helpful in avoiding plating) makes it an ideal candidate for high-energy Li-ion batteries (LIBs). However, it is faced with severe issues like high crystallographic expansion (~320%), slow lithium diffusion, and high reactivity with electrolyte at higher SOCs. All of it leads to particle cracking, isolation, and electrode delamination resulting into poor cycle life performance. To harness the true potential of Silicon, we proposed an improvised Si/Gr composite anode balancing the high-specific capacity and cycle life. We investigated a novel binder formulation for Si-rich/Gr composite to enable high-specific capacity without compromising on life cycle. We demonstrated a robust and stable solid-electrolyte interface (SEI) formation by optimizing the electrolyte additive and formation protocol. Coupling our Si/Gr anode with high-energy Ni-rich cathode at appropriate capacity ratio (N/P) provides high-energy density (> 400 Wh/Kg) for LIBs.

Non-Flammable Electrolyte for Large-Scale Ni-Rich Li-Ion Batteries: Reducing Thermal Runaway Risks

This research explores the properties and applications of flame-retardant esters (FREs), specifically triethyl phosphate (TEP) and tributyl phosphate (TBP), within electrolyte systems. The investigation assesses their roles as additives (30%v/v) and primary solvents (80%v/v) in conjunction with carbonate-based electrolytes (1.0 M LiPF6 in EC:DEC:EMC) and a novel non-flammable electrolyte formulation (1.2 M LiPF6 in 70%v/v TEP with 30%v/v fluoroethylene carbonate, FEC). Results indicate that incorporating FREs as additives adversely affects cell performance and maintain flammability risks, necessitating alternative strategies for achieving nonflammability. However, utilizing FREs as primary solvents alongside carbonate solvents shows promise for developing non-flammable electrolytes, despite concerns such as reductive decomposition that may limit suitability for certain battery cells. Conversely, the incorporation of 70%v/v FREs with 30%v/v FEC in the new electrolyte formulation yields a stable solid electrolyte interface, inhibiting FRE decomposition and sustaining battery cycling performance. This combination offers a potential solution for producing non-flammable electrolytes, serving as a viable alternative to solid-state electrolytes. The compatibility of the 1.2 M LiPF6 in TEP:FEC, 70:30 %v/v formulation with existing battery manufacturing processes further enhances its applicability. Figure 1

Ion Conduction Mechanism and Interfacial Stability in Fluorine Containing Lithium Argyrodite Electrolytes for Solid-State Lithium-Sulfur Batteries

Solid-state lithium-sulfur batteries (SSLSBs) hold great potential as a safe and energy-dense storage technology for wide variety of applications. Among solid-state electrolytes, halogen-doped lithium argyrodites have become an attractive category. This is attributed to their notable features, including high lithium-ion conductivity (~10-3 S/cm), favorable elastic stiffness (~ 30 GPa), and low flammability, making them promising candidates for enhancing the performance of SSLSBs.Despite their potential, SSLSBs based on sulfide faces challenges due to a limited atomic-scale understanding of ion-conduction, charge transport, structural evolution, and interfacial reactions such as dendrite growth, electrolyte decomposition. Here we employ a combination of density functional theory calculations, and ab initio molecular dynamics simulations to address this challenge for fluorinated argyrodites. Specifically, using accurate materials modeling, we design fluorine-containing argyrodite electrolytes that simultaneously offer enhanced (a) Li-ion conduction facilitated by unique Li-disorder induced by fluorine and other halogen co-dopants, and (b) stability against Li-anode owing to formation of a stable solid-electrolyte interface containing conductive species (Li3P), alongside LiCl and LiF. We will discuss these results in the context of accelerating design of novel solid-state electrolytes for long-lived, stable, and high-energy density SSLSBs.

Diffusion of Carbon Quantum Dots on Lithium Liquid Metal for Artificial SEI

AbstractThe unstable solid electrolyte interface (SEI) formed on the surface of Li metal can induce dendrite growth, resulting in capacity fading, battery short circuit, and other problems, thus hindering the practical application of Li metal battery. In order to obtain stable and effective SEI, it is an effective strategy to construct an ideal artificial SEI (ASEI) by regulating the composition and structure of the interface. Among the inorganic materials used in the construction of ASEI, carbon quantum dots (CQDs) stand out as promising material due to their small size and abundant active sites. Herein, benefiting from the fluidity, surface smoothness, and high reactivity of liquid metal, combined with the use of N‐doped CQDs as dispersing particles, a surface modification method to achieve uniform dispersion of particles within the liquid metal is proposed. This technique offers a low‐cost solution for achieving uniform dispersion of little quantities of N‐doped CQDs (single dose < 0.1 mg cm−2) while ensuring enhanced interface adhesion to realize the construction of dense, strong and uniform ASEI. The corresponding symmetrical cells show lower voltage polarization and outstanding cycling stability than the bare Li electrode.

Mitigating the capacity fading of silicon nanoparticles through double carbon coatings and cobalt doping

Silicon (Si) is considered a highly promising anode material for lithium-ion batteries (LIBs), attributing to its suitable working potential and high specific capacity. Nevertheless, the enormous volume expansion during the lithiation, poor electron conductivity, and low lithium-ion (Li+) diffusion rate limit the application of Si anodes. Here, we design a novel single carbon layer and carbon nanotubes (CNT) coated Si nanoparticle (Si NP@C@CNT composites), in which the single carbon layer derived from citric acid separates between Si nanoparticle (Si NP), effectively avoiding the aggregation of Si NP, while the external carbon framework (CF) composed of CNT boosts the electrical contact between Si NP. Such micro-morphology structure can reduce the stresses during lithiation and promote the formation of stable solid electrolyte interface. Besides, the metallic cobalt (Co) and CNT can effectively enhance electrode conductivity and promote rapid electron transfer. The electrochemical testing results indicate that Si NP@C@CNT anode presents faster electrochemical reaction kinetics with excellent cycle stability (1055.1 mAh g−1 after 300 cycles at 0.5 A g−1) and rate performance (809.9 mAh g−1 at 5 A g-1). The special capacities and capacity retention of Si NP@C@CNT composites are 885.3 mAh g−1 and 85.9% after 1000 cycles at 1 A g−1. In addition, the constructed full-cell NCM811// Si NP@C@CNT shows well reversible capacity. This research provides a novel idea for Si -based anode with excellent cycling stability, high electron transfer and fast Li+ diffusion ability for LIBs.

Joule heating for structure reconstruction of hard carbon with superior sodium ion storage performance

Hard carbon anode for sodium ion batteries still remains many challenges including insufficient cycling life and initial Coulombic efficiency (ICE), weak rate capability and poor compatibility in common ester electrolytes. Here, we propose a Joule heating post-treatment including multifield sintering method to reconstruct the structure of hard carbon from thick graphene layers to more disordered vortex layer structure composed of thin and curved graphite-like domains. The molecular dynamics simulation and differential charge density distribution demonstrate the crucial effect of electric field in strengthening the interaction between the polar molecule groups and the graphene layer, leading to the distortion and expanding of graphene layer. This is a universal and highly efficient strategy to modify various hard carbons within minutes. The optimized hard carbon anode exhibits exceptional rate capability and cycling stability with a high retention rate of 88.4% after 15,000 cycles at 10C in ether electrolyte. It also displays remarkably improved reversible capacity, initial Coulombic efficiency ICE of 89.5% and cycling stability in ester electrolyte. It is revealed by in-situ electrochemical impedance spectroscopy and atomic force microscopy that the spontaneous formation of a thin, stable and inorganic substance-rich solid electrolyte interface layer with significantly improved mechanical property is largely responsible for the outstanding sodium-ion transport kinetics and long lifespan.

Fabrication of a Porous Copper/Graphite/Zirconium Oxide Hybrid Anode via Screen Printing for Lithium‐Ion Batteries

AbstractRedesigning anode structures in Li‐ion batteries (LIBs) has been a focus of research aimed at surpassing the energy density of conventional LIBs. Although anode‐free LIBs present a promising architecture, their low Coulombic efficiency is a major drawback. This paper introduces a novel hybrid anode that integrates the current collector (CC) and active materials into a single, cohesive porous structure, which supports both de/intercalation and de/plating reactions. The hybrid anode consists of a porous Cu matrix with embedded ZrO2 powders and graphite; the quantity of graphite is only a third of that present in a traditional graphite anode. The porous structure and additives enhance the electrochemical performance of the hybrid anode by minimizing the Li–electrolyte interactions, forming a stable solid–electrolyte interface and Li4Zr3O8 passivation layer, and reducing the nucleation overpotential. Especially, the unique surface morphology, characterized by a negative curvature between sintered Cu particles, lowers the diffusion potential, which further reduces the nucleation overpotential. Additionally, the periodic mesh‐imprinted top surface, created via screen printing, promotes uniform Li plating. The results demonstrate that the cycling performance and energy density offered by the fabricated hybrid anode are superior to those of conventional graphite anodes.

Sustainable conversion of vine shoots and pig manure into high-performance anode materials for sodium-ion batteries

Sodium-ion batteries (SIBs) are considered promising candidates for future grid energy storage, with hard carbons emerging as key commercial anode materials. This study presents a novel approach to synthesize N-doped hard carbons via co-hydrothermal treatment of vine shoots and pig manure and subsequent thermal annealing of the resulting hydrochar. This method enhances the development of micro- and ultra-microporosity in the synthesized hard carbons, with nitrogen, and to a lesser extent phosphorus and sulfur, introduced as doping elements. Furthermore, the incorporation of hydrochloric acid during the hydrothermal step promotes biomass hydrolysis, leading to increased mesoporosity and the formation of microsphere clusters. In the realm of electrochemical performance, an investigation into various ester- and ether-based electrolytes has revealed NaPF6 in diglyme as the best formulation, thanks to its thinner and more stable solid electrolyte interface (SEI). Using this electrolyte, the best-performing electrode showed an initial Coulombic efficiency (ICE) of 73 %, with reversible capacities of 239, 180, 86, and 57 mAh g−1 at 0.1, 1, 5, and 10 A g−1, respectively. In addition, the electrode exhibited a remarkable capacity retention of 88 % after 250 cycles as well as a compatible behavior when paired with a NVPF-based cathode.

Revealing the dynamic interface evolutions of electrochemical pre-lithiated graphite electrodes in practical workplace atmospheres

The electrochemical pre-lithiation (EC-PrLi) method using half-cell configuration exhibits great potential in constructing a uniform and stable solid electrolyte interface (SEI) in lithium-ion batteries (LIBs). The exposure procedures for EC-PrLi electrodes are inevitable during electrode transfer and cell fabrication, the SEI structure and stability of pre-lithiated electrodes are significantly affected for the high reactivity of SEI in ambient air. Hence, the stability of pre-lithiated electrodes is one of the most significant indexes reflecting the possibility for large-scale applications. Here, graphite electrodes are chosen for EC-PrLi, revealing for the first time the dynamic interface evolution of pre-lithiated graphite electrodes exposed to practical environments (glove box:GB and dry room:DR). The SEI of the lithiated electrode (D-12) exposed to a more realistic environment (DR) evolves into unstable and thin (∼1.5 nm) poor-LiOH SEI. The electrochemical performance changes of lithiated electrodes exposed to different conditions are being revealed. The lithiated graphite electrode (D-12) exhibits poor rate characteristics (314.6 mAh g−1 at 0.05 C and 22.8 mAh g−1 at 1.0 C) and cycling stability (capacity retention rate of 81.3 %). This work reveals the dynamic interface evolution of EC-PrLi graphite electrodes in practical environments, providing guidance for the broader application of pre-lithiation technology in practical.