Unravelling the anionic stability of an ether-based electrolyte with a hard carbon or metallic sodium anode for high-performance sodium-ion batteries.

In hard carbon (HC) anodes, elucidating the relationship between the solid electrolyte interphase formation and the solvated Na+ co-intercalation mechanism is crucial, particularly considering different anionic salts in ether-based electrolytes. Here, we comprehensively explore the impact of different anionic salts on the electrochemical performance of HC/Na half-cell and elucidate the underlying mechanism through experimental studies and theoretical calculations. The surface morphology of the HC anode and its interphasial property are further investigated to evaluate the differences endowed by the presence of various anionic salts in diglyme (2G). The HC/Na half-cells with NaPF6-2G and sodium trifluoromethanesulfonate (NaCF3SO3)-2G display superior electrochemical performance with faster kinetics and lower interfacial resistance than those with NaClO4-2G, sodium bis-(fluorosulfonyl) imide (NaFSI)-2G and sodium bis-(trifluoromethanesulfonyl) imide (NaTFSI)-2G. NaClO4-2G forms a relatively thick interphase layer with high resistance at the electrode/electrolyte interface owing to its insufficient stability. NaFSI-2G and NaTFSI-2G exhibit severe side reactions with Na metal, producing a thick interphase layer on the HC surface with high interfacial resistance from excess electrolyte decomposition, thus deteriorating the electrochemical performance. In summary, the study on the stability of different anionic salts in ether-based electrolyte for the HC anode with the intercalation mechanism provides valuable insights for screening appropriate conductive salts for high-performance sodium-ion batteries, especially when considering Na metal counter/reference electrodes.

Fluorinated ester additive to regulate nucleation behavior and interfacial chemistry of room temperature sodium-sulfur batteries.

Room temperature sodium-sulfur (RT Na-S) batteries are considered as advanced energy storage technology due to their low cost and high theoretical energy density. However, challenges such as the growth of sodium dendrite and dissolution of sodium polysulfides significantly hinder the electrochemical performance. Herein, we developed a propylene carbonate (PC)-based electrolyte with Methyl 2-Fluoroisobutyrate (MFB) as an additive. The ester group in the MFB additive is capable of participating in and reconfiguring the coordination of their Na+ solvated structures, thereby lowering the desolvation barrier and regulating the Na anode's interfacial reaction and nucleation behavior. The polar C-F bond at the other end helps to reduce the lowest unoccupied molecular orbital (LUMO) energy of the MFB additive, enabling the preferential decomposition of MFB to form the F-rich inorganic phase strong polar solid electrolyte interphase (SEI), contributing to the inhibition of Na dendrite growth, the accumulation of dead Na. In addition, NaF-riched cathode electrolyte interphase (CEI) was also observed on sulfur-based cathode, which can effectively inhibited the shuttle effect. Consequently, the developed RT Na-S battery exhibit excellent electrochemical performance.

New-Concept Metal-Based Artificial SEI Film of Polyimide Anode Material in Dual-Ion Batteries.

Organic material polyimides (PI) are widely used in secondary batteries due to green safety, renewables, and structural designability. However, problems such as low conductivity and structural damage of polyimide electrode materials seriously limit its practical application. Herein, an innovative in situ modification method with CaCl2 is used to construct pure Al metal-based artificial SEI film on the surface of PI to improve the electrochemical performance of organic dual-ion batteries. Compared with the pure PI material, it has a noticeable improvement in cycle performance. Importantly, characterization results of the physicochemical analysis show that the pure Al metal-based artificial SEI film formed in situ on the surface of the PI material plays a key role in isolating and improving the electrochemical performance of PI anode materials. The innovative approach offers an efficacious strategy to construct pure metal-based artificial SEI films for the practical implementation of organic batteries.

The influence of P-toluenesulfonyl isocyanate on the solvation structure and solid electrolyte interphase formation on graphite anode under high temperatures.

The formation and stability of the solid electrolyte interphase (SEI) play a crucial role in determining the performance and lifespan of lithium-ion batteries (LIBs) at evaluated temperatures. Electrolyte additives have emerged as promising candidates for modulating the formation kinetics and stability of the SEI layer. In this study, molecular dynamics (MD) and ab initio molecular dynamics (AIMD) simulations were employed to investigate the influences of P-toluenesulfonyl isocyanate (PTSI) as an electrolyte additive in the LiPF6/EC/DMC electrolyte on the SEI formation process on the graphite anode under high temperatures. MD simulations revealed that PTSI induces modifications in the solvation structure, resulting in two ethylene carbonate (EC) and two dimethyl carbonate (DMC) molecules in the first solvation shell of Li+. Furthermore, the PTSI additive suppressed the decomposition of solvent molecules and PF6 anions in the LiPF6/EC/DMC/PTSI electrolyte under high temperatures according to the AIMD simulations, contributing to a more stable SEI layer. Moreover, this suppression can be attributed to the reduced reactivity of solvent molecules and salt anions, as evidenced by the enhanced bond strength and decreased bond length. These microscopic insights provide a multi-faceted understanding of the functionality of PTSI additives, facilitating the rational design of novel additives.

Li-Ga Alloy-Contained Hybrid Solid Electrolyte Interphase Induced by In Situ Polymerization for High-Performance Lithium Metal Batteries.

Construction of quasi-solid-state lithium metal batteries (LMBs) by in situ polymerization is considered a key strategy for the next generation of energy storage systems with high specific energy and safety. Poly(1,3-dioxolane) (PDOL)-based electrolytes have attracted wide attention among researchers, benefiting from the low cost and high ionic conductivity. However, interfacial deterioration and uncontrollable growth of lithium dendrites easily appeared in LMBs due to the high reactivity of lithium metal, resulting in the failure of LMBs. In this work, a strategy is developed of using Ga(OTF)3 as the initiator to obtain a PDOL-based gel electrolyte (GaPD). In addition, a hybrid stable solid electrolyte interphase (SEI) of lithium fluoride/Li2O/Li-Ga alloys is observed on the surface of lithium metal. Combined with density functional theory calculations, the hybrid SEI shows high affinity toward Li+, indicating that a uniform deposition of Li+ could be achieved. Therefore, the Li/GaPD/Li cell operates stably for 1600 h at room temperature. In addition, the LiFePO4/GaPD/Li cell retains a capacity retention rate of 90.2% over 200 cycles at 1 C. This work provides a reference for the practical application of in situ polymerization technology in high-performance and safe LMBs.

Li2MoO4 tailored Anion-enhanced Solvation Sheath Layer Promotes Solution-phase Mediated Li-O2 Batteries.

The high overpotential of Li-O2 batteries (LOBs) is primarily triggered by sluggish charge transfer kinetics at the reaction interfaces. A typical LiBr redox mediator (RM) catalyst can effectively reduce the battery's overpotential. However, it is prone to shuttling and corroding the Li anode, leading to RM loss and reduced energy efficiency. To address these challenges, we introduced Li2MoO4 into the LiBr-containing electrolyte to promote the solution-phase mediated LOBs. This addition tailors the anion-enhanced Li+ solvation sheath layer and forms a robust anion-derived solid electrolyte interphases (SEI) on the Li anode. The robust SEI effectively mitigates the corrosion of soluble Br3-/Br2 and attacks by highly reactive oxygen species. Additionally, the dispersed and high-density Li2MoO4 exhibits strong adsorption capabilities for O2/LiO2 and Br-related species during the discharge/charge process, thereby promoting the growth and decomposition of Li2O2 in the solution phase and inhibiting the shuttle effect of Br-related species in LOBs. Consequently, the LOBs demonstrate exceptional cycling stability (415 cycles) and high energy efficiency (86.2%), paving the way for the sustainable development and practical application of these battery systems.

Ferroelectric Dipoles Tailoring Solid-Electrolyte-Interphase Chemistry to Enable Reversible Lithium Metal Batteries.

Solid-electrolyte interphase (SEI) plays a decisive role in building reliable Li metal batteries. However, the scarcity of anions in Helmholtz layer (HL) caused by electrostatic repulsion usually leads to the inferior SEI derived from solvents, resulting in dendrites and 'dead' Li. Therefore, regulating the distribution of anions in electric double layer (EDL) and continuously introducing more anions into HL to tailor anions-derived SEI is crucial for achieving stable Li plating/stripping. Herein, by jointly utilizing the controlled defects of reduced graphene oxide (rGO) and the oriented dipoles of ferroelectric BaTiO3 (BTO), the rGO-BTO composite layer sustainedly brings more TFSI- and NO3- into anion-defecient HL, promoting favorable decomposition of anions and guiding the generation of robust and fast-Li+-transport SEI containing more inorganics LiF and Li3N species. Thus, the resulting Li deposit shows smooth and dense morphologies without dendrites, leading to high average Coulombic efficiency. The Li//Cu@rGO-BTO (10 mAh cm-2 plated Li) cell exhibits an enhanced Li plating/stripping stability (2700 h) and a higher rate capability. The LiFePO4 full cell (N/P=~6.3) using rGO-BTO displays an enhanced capacity retention (82.0% @ 430 cycles). This work provides a new insight on the construction of robust SEI by regulating the distribution of anions within EDL.

Revitalizing Lithium Metal Batteries: Strategies for Tackling Dead Lithium Formation and Reactivation.

Lithium (Li) metal batteries (LMBs) are among the most promising candidates for future battery technology due to their high theoretical capacity and energy density. However, the formation of dendritic Li, characterized by needle-like structures, poses serious safety issues. To address this, numerous methods are developed to prevent Li dendrite formation. Another significant challenge in LMBs is the formation of inactive Li, known as dead Li, which significantly impacts their Coulombic efficiency and overall performance. This review explores the issues surrounding dead Li in LMBs, specifically focusing on electrically isolated Li metal and the repeatedly generated solid electrolyte interphase (SEI). Advanced techniques for characterizing inactive Li are discussed, alongside various strategies designed to activate or suppress dead Li, thus restoring battery capacity. The review summarizes recent advancements in research related to the activation, reuse, and prevention of dead Li, offering valuable insights for enhancing the efficiency and safety of LMBs. This comprehensive overview provides fundamental guidance for the practical application of Li metal anodes and similar metal batteries.

Non-consumable gamma-cyclodextrin additive constructing anti-solvation interphase realizing dendrites free and high-performance lithium metal batteries.

Relying on surpassing high theoretical capacity (3,865 mAh/g) and the lowest relative electrode potential (0 V vs. metallic Li), lithium metal batteries (LMBs) have been regarded as the "holy grail" of next-generation energy storage technology. Whereases, the instability of pristine solid electrolyte interphase (SEI) layers and the disorderly growth of lithium dendrites are still significant challenges to the commercialisation of LMBs. In this study, a novel approach is introduced to homogenise Li deposition by incorporating an environmentally friendly electrolyte additive, gamma-cyclodextrin (γ-CD), in ether-based electrolytes. Through host-guest interactions, γ-CD additives not only form inclusion complexes to improve Li+ transference number to 0.86 but also encapsulate TFSI- anions and other solvent molecules within the "cavity effect" to relieve unfavourable solvent effect. Electrochemical characterisations demonstrate that introducing 1 wt% γ-CD elevates the oxidation decomposition voltage of ether electrolytes to 4.15 V, thereby inhibiting the decomposition of ether electrolytes and reducing the fracture of SEI layers. According to reduce the nucleate potential, the Li//Cu half battery exhibits improved stability for 100 cycles, with an improved average Coulombic efficiency (CE) maintained above 98.4 %. Even if applied at high current densities of 5.0 mA cm-2 for a capacity of 1.0 mAh cm-2, the Li//Li symmetric battery can cycle for over 800 h, and the Li//Li4Ti5O12 (LTO) full battery retains 98.8 % of the initial capacity after 1,400 cycles.

The Introduction of a BaTiO3 Polarized Coating as an Interface Modification Strategy for Zinc-Ion Batteries: A Theoretical Study.

Aqueous zinc-ion batteries (AZIBs) have become a promising and cost-effective alternative to lithium-ion batteries due to their low cost, high energy, and high safety. However, dendrite growth, hydrogen evolution reactions (HERs), and corrosion significantly restrict the performance and scalability of AZIBs. We propose the introduction of a BaTiO3 (BTO) piezoelectric polarized coating as an interface modification strategy for ZIBs. The low surface energy of the BTO (110) crystal plane ensures its thermodynamic preference during crystal growth in experimental processes and exhibits very low reactivity toward oxidation and corrosion. Calculations of interlayer coupling mechanisms reveal a stable junction between BTO (110) and Zn (002), ensuring system stability. Furthermore, the BTO (110) coating also effectively inhibits HERs. Diffusion kinetics studies of Zn ions demonstrate that BTO effectively suppresses the dendrite growth of Zn due to its piezoelectric effect, ensuring uniform zinc deposition. Our work proposes the introduction of a piezoelectric material coating into AZIBs for interface modification, which provides an important theoretical perspective for the mechanism of inhibiting dendrite growth and side reactions in AZIBs.

Monofluorinated Phosphate with Unique P-F Bond for Nonflammable and Long-Life Lithium-Ion Batteries.

Lithium-ion batteries (LIBs) with conventional carbonate-based electrolytes suffer from safety concerns in large-scale applications. Phosphates feature high flame retardancy but are incompatible with graphite anode due to their inability to form a passivated solid electrolyte interphase (SEI). Herein, we report a monofluorinated co-solvent, diethyl fluoridophosphate (DEFP), featuring a unique P-F bond that allows a trade-off between safety and electrochemical performance in LIBs. The P-F bond in DEFP weakens ion-dipole interactions with Li+ ions, lowering the desolvation barrier, and simultaneously reduces the lowest unoccupied molecular orbital (LUMO) of DEFP, promoting the formation of a robust and inorganic-rich SEI. Additionally, DEFP exhibits improved thermal stability due to both robust SEI and the inherent flame-retardant properties of the P-F bond. Consequently, the optimized DEFP-based electrolyte exhibits improved cyclability and rate capacity in LiNi0.8Co0.1Mn0.1O2 || graphite full cells compared with triethyl phosphate-based electrolytes and commercial carbonate electrolytes. Even at a low E/C ratio of 3.45 g Ah-1, the 1.16 Ah NCM811||Gr pouch cells achieve a high capacity retention of 94.2% after 200 cycles. This work provides a promising approach to decouple phosphate safety and graphite compatibility, paving the way for safer and high-performance lithium-ion batteries.

Selective Methylation of Cyclic Ether Towards Highly Elastic Solid Electrolyte Interphase for Silicon-based Anodes.

Silicon (Si)-based anodes offer high theoretical capacity for lithium-ion batteries but suffer from severe volume changes and continuous solid electrolyte interphase (SEI) degradation. Here, we address these challenges by selective methylation of 1,3-dioxolane (DOL), thus shifting the unstable bulk polymerization to controlled interfacial reactions and resulting in a highly elastic SEI. Comparative studies of 2-methyl-1,3-dioxolane (2MDOL) and 4-methyl-1,3-dioxolane (4MDOL) reveal that 4MDOL, with its larger ring strain and more stable radical intermediates due to hyperconjugation effect, promotes the formation of high-molecular-weight polymeric species at the electrode-electrolyte interface. This elastic, polymer-rich SEI effectively accommodates volume changes of Si and inhibits continuous side reactions. Our designed electrolyte enables Si-based anode to achieve 85.4% capacity retention after 400 cycles at 0.5 C without additives, significantly outperforming conventional carbonate-based electrolytes. Full cells also demonstrate stable long-term cycling. This work provides new insights into molecular-level electrolyte design for high-performance Si anodes, offering a promising pathway toward next-generation lithium-ion batteries with enhanced energy density and longevity.

Inorganic-Enriched Solid Electrolyte Interphases: A Key to Enhance Sodium-Ion Battery Cycle Stability?

The characteristics of solid electrolyte interphase (SEI) at both the cathode and anode interfaces are crucial for the performance of sodium-ion batteries (SIBs). The research demonstrates the merits of a balanced organic component, specifically the organic sodium alkyl sulfonate (ROSO2Na) featured in this work, in conjunction with the inorganic sodium fluoride (NaF), to enhance the interfacial stability. Using a customized electrolyte, it has optimized the interphase, curbing excess NaF production, and created a thin and uniform NaF/ROSO2Na-rich SEI layer. It offers exceptional protection against interface deterioration, transition metal dissolution, and concurrently ensures a consistent reduction in interfacial impedance. This creative approach results in a substantial improvement in the performance of both the Na0.9Ni0.4Fe0.2Mn0.4O2 cathode and the hard carbon anode. The cathode demonstrates remarkable average Coulombic efficiency exceeding 99.9% and a capacity retention of 81% after 500 cycles. Furthermore, the Ah-level pouch cell has shown outstanding performance with an 87% capacity retention after 400 cycles. Moving beyond the prevailing focus on inorganic-rich SEI, these results highlight the effectiveness of the customized organic-inorganic hybrid SEI formulation in improving SIB technology, offering an adaptable solution that ensures superior interfacial stability.

In Situ Formation of Stable Dual-Layer Solid Electrolyte Interphase for Enhanced Stability and Cycle Life in All-Solid-State Lithium Metal Batteries.

All-solid-state lithium metal batteries have emerged as a promising solution to overcoming the energy density and safety challenges associated with conventional lithium-ion batteries. Solid polymer electrolytes, particularly those based on poly(vinylidene fluoride) (PVDF) and dimethylformamide (DMF), demonstrate significant potential. However, interfacial side reactions between residual DMF solvents and lithium metal present substantial challenges. In this study, we investigate the in situ formation of solid electrolyte interphase protective layers to mitigate these side reactions. By incorporating F-rich additives, such as fluoroethylene carbonate and lithium difluorophosphate, we successfully establish a dual-layer inorganic SEI structure characterized by an outer LiF layer and an inner Li2O layer. Consequently, our approach extends the cycle life of lithium symmetric batteries to 3000 h. Additionally, the Li||LiFePO4 solid-state battery demonstrates exceptional stability, enduring 400 cycles at a 1C rate with an impressive capacity retention of 84%. This strategic methodology effectively leverages the benefits of residual solvents, ensuring both enhanced battery efficiency and long-term operational stability for PVDF-based all-solid-state lithium metal batteries.

Electrochemically and chemically in-situ interfacial protection layers towards stable and reversible Zn anodes.

Aqueous zinc metal batteries (AZMBs) have received widespread attention for large-scale sustainable energy storage due to their low toxicity, safety, cost-effectiveness. However, the technology and industrialization of AZMBs are greatly plagued by issues of Zn anode such as persistent dendrites and parasitic side reactions, resulting in rapid capacity degradation or battery failure. Electrochemically or chemically in-situ interfacial protection layers have very good self-adaption features for stability and reversibility of Zn anodes, which can also be well matched to current battery manufacturing. However, the in-situ interfacial strategies are far from the practical design for effective Zn anodes. Therefore, a targeted academic discussion that serves the development of this field is very urgent. Herein, the comprehensive insights on electrochemically and chemically in-situ interfacial protection layers for Zn anode were proposed in this review. It showcased a systematic summary of research advances, followed by detailed discussions on electrochemically and chemically in-situ interfacial protection strategies. More importantly, several crucial issues facing in-situ interfacial protection strategies have been further put forward. The final section particularly highlighted a systematic and rigorous scheme for precise designing highly stable and reversible in-situ interface for practical zinc anodes.

Exploring the Impact of In Situ-Formed Solid-Electrolyte Interphase on the Cycling Performance of Aluminum Metal Anodes.

Unwanted processes in metal anode batteries, e.g., non-uniform metal electrodeposition, electrolyte decomposition, and/or short-circuiting, are not fully captured by the electrolyte bulk solvation structure but rather defined by the electrode-electrolyte interface and its changes induced by cycling conditions. Specifically, for aluminum-ion batteries (AIBs), the role of the solid-electrolyte interphase (SEI) on the Al0 electrodeposition mechanism and associated changes during resting or cycling remain unclear. Here, we investigated the current-dependent changes at the electrified aluminum anode/ionic liquid electrolyte interface to reveal the conditions of the SEI formation leading to irreversible cycling in the AIBs. We identified that the mechanism of anode failure depends on the nature of the counter electrode, where the areal capacity and cycling current for Al0 electrodeposition dictates the number of successful cycles. Notwithstanding the differences behind unstable aluminum anode cycling in symmetrical cells and AIBs, the uniform removal of electrochemically inactive SEI components, e.g., oxide-rich or solvent-derived organic-rich interphases, leads to more efficient cycling behavior. These understandings raise the importance of using specific conditioning protocols for efficient cycling of the aluminum anode in conjugation with different cathode materials.

Achieving Higher Critical Current Density in LGPS-Based Lithium Metal Batteries via a Synergistic Interlayer for Physical Inhibition and Chemical Scavenging of Lithium Dendrites.

Li10.35Ge1.35P1.65S12 (LGPS) electrolyte has garnered attention due to its high ionic conductivity and processability. However, its strong incompatibility with lithium metal hinders its practical application. Conventional interlayer strategy isolates Li from LGPS, avoiding the detrimental side reactions, but lithium dendrite penetration is still a problem. To address the aforementioned challenges, we develop a PVDF-HFP-supported PDOL-based interlayer (PDOL/PVDF-HFP), which stabilizes the LGPS/Li interface by synergistically physically inhibiting and chemically scavenging lithium dendrites. The multifunctional feature of the interlayer comes from the use of a bifunctional initiator, InCl3. On the one hand, InCl3 induces the polymerization of DOL, forming a physical separator and protecting lithium from LGPS; on the other hand, in situ reactions between In3+/Cl- and Li form a LiCl/LiF/LiIn hybrid SEI, homogenizing the surface Li+ flux and suppressing lithium dendrite formation and penetration. In addition, an unexpected dynamic microdendrite scavenging is realized by virtue of the side reactions of LGPS/Li, which converts the undesirable reaction to be an advantage in our design. Benefiting from the comprehensive advantages of such design, the constructed sulfide-based solid-state batteries achieve a super low interfacial impedance of 5.1 Ω, a high critical current density (CCD) value over 5 mA/cm2, and a super long cycling stability over 8000 h. Our synergistic interlayer strategy would open an effective avenue for solving interfacial challenges for practical sulfide-based solid-state batteries.

Negative Effect of the Calendering Process on the Interphase Formation and Electrochemical Behavior of Reduced Graphene Oxide Electrodes.

Many studies on electrode material development for rechargeable batteries have focused on improving the intrinsic physicochemical and electrochemical properties of active materials, but the electrochemical performances of batteries are exhibited by the overall electrode unit consisting of active materials, conductive additives, and a binder. Additionally, the electrodes have undergone an essential calendering process to enhance the physical contact between those components. Therefore, the electrochemical behavior and performance of a cell should be analyzed at the electrode level, as the inherent properties of active materials might be changed in electrode preparation, including the calendaring process and real-operating environments. In this study, we aimed to understand the electrochemical properties of the reduced graphene oxide (RGO)-containing electrodes rather than the RGO-active materials by studying the changes in the RGO electrode before and after the calendering process. Specifically, the study investigates the effect of the calendering process on the electrochemically active interphase formation and electrochemical properties of the RGO electrode. We found that the calendering process deteriorates the electrochemical properties of RGO electrodes by impeding enough electrolyte wetting, limiting the formation of thin and stable solid-electrolyte interphase, and leaving unreacted RGO sheets. Additional experiments with carbon-coated silicon/RGO composite electrodes demonstrate that after the calendering process, the sequential participation of Si/C particles in the electrochemical reaction resulted in much more severe capacity degradation over repeated cycling processes. The studies suggest that fine-controlling the number of RGO sheets and maintaining enough distance between those sheets even after the calendering process are required for the utilization of RGO in rechargeable batteries.

Cationic Covalent Organic Framework-Modified Polypropylene Separator for High-Performance Lithium Metal Batteries.

As an important component of lithium batteries, the wettability and thermal stability of the separator play a significant role in cell performance. Despite the availability of numerous commercial separators, issues such as low ion selectivity and poor thermal stability continue to limit the efficiency and reliability of the batteries. Herein, two cationic covalent organic frameworks (Br-COF and TFSI-COF) with abundant imidazole cationic groups were designed to modify commercial polypropylene (PP) separators. The strong lithium-ion affinity of the cationic COF enables the effective dissociation of lithium salt ion clusters, simplifying the solvent structure of lithium ions to promote lithium ions transport. Additionally, solvent anions can be anchored to the cationic COF by electrostatic interactions, reducing side reactions on the lithium metal anode surface to form a favorable SEI layer, which can effectively inhibit the growth of lithium dendrites. The rapid dissociation of anions in lithium salts with some organic solvents and cationic COFs was revealed by a molecular dynamics simulation. A LiF-rich SEI layer on the lithium metal anode surface was formed, which can speed up Li+ transport at interfaces, leading to consistent lithium deposition and outstanding battery performance. The ordered porous structure of the cationic COF provides interconnected and continuous channels, improving the wettability between the liquid electrolyte and separators, which is conducive to ion transport. When paired with a LiFePO4 cathode and electrolyte (1.0 M LiTFSI in DEC: EC: DMC = 1:1:1), the LiFePO4/TFSI-COF@PP/Li cell demonstrates a prominent cycling capacity of 148.0 mAh g-1 at 0.5 C with a Coulombic efficiency of 98.0% in the first cycle, and the capacity retention is 82.0% after 100 cycles, showing good cycling stability. Thus, this investigation provides inspiration for the expansion of cationic COF-modified separators for next-generation lithium metal batteries.

Ultra-Stable Aqueous Zinc Anodes: Enabling High-Performance Zinc-Ion Batteries via a ZnSiF6-Derived Protective Interphase.

Zinc-ion batteries (ZIBs) hold immense promise as next-generation energy storage solutions, however, the practical application of zinc anodes is hindered by dendrite formation and parasitic side reactions. Engineering a stable solid- eletrolyte interphase (SEI) is crucial for addressing these issues. This study proposes a novel strategy to enhance Zn anode performance by incorporating a ZnSiF6 additive into a standard ZnSO4 (ZSO) electrolyte. The ZnSiF6 additive facilitates the formation of a stable, fluorine-rich SEI on the Zn anode surface. Characterization reveals a hierarchical SEI structure, primarily composed of porous alkali zinc sulfate (ZHS) with embedded ZnF2. This unique architecture promotes rapid zinc ion desolvation and efficient transport, enhances corrosion resistance, and mitigates hydrogen evolution. Consequently, ZnSiF6-modified cells exhibit exceptional cycling stability, exceeding 3000 hours at 0.5 mA cm-2 and 560 hours at 10 mA cm-2, significantly outperforming ZSO-based cells. The modified cells also achieve high areal capacities (10 mAh cm-2), indicating superior zinc utilization. This work provides key insights for designing stable electrode/electrolyte interfaces, contributing to the development of high-performance aqueous ZIBs.