Anode Surface Research Articles

Tailoring Zn2+ Flux by an Ion Acceleration Layer Modified Separator for High-Rate Long-Lasting Zn Metal Anodes.

A large concentration gradient originating from sluggish ion transport on the surface of Zn metal anodes will result in uneven Zn2+ flux, giving rise to severe dendrite growth, especially at high current density. Herein, an ion acceleration layer is introduced by a facile separator engineering strategy to realize modulated Zn2+ flux and dendrite-free deposition. Zinc hexacyanoferrate as the modifying agent featuring strong zincophilicity and rapid diffusion tunnel can enable fast trap for Zn2+ near the electrode surface and immediate transport onto deposition sites, respectively. The ion acceleration effect is substantiated by improved ion conductivity, decreased activated energy, and promoted Zn2+ transference number, which can moderate concentration gradient to guide homogenous Zn2+ flux distribution. As a result, the separator engineering guarantees Zn||Zn symmetrical cells with long-term stability of 2700 h at 2 mA cm-2, and 1770 h at a large current density of 10 mA cm-2. Moreover, cycling stability and rate capability for full cells with different cathodes can be substantially promoted by the modified separator, validating its superior practical feasibility. This study supplies a new scalable approach to tailoring ion flux near the electrode surface to enable robust Zn metal anodes at a high current density.

Hard carbon anode materials for hybrid sodium-ion/metal batteries with high energy density

Interest in sodium-ion batteries (SIBs) as a lower-cost alternative to lithium-ion batteries (LIBs) is growing in both scientific and industrial fields. However, uneven premature sodium deposition and dendrite formation during cycling pose a serious safety threat, significantly limiting the application of SIBs. Achieving reversible and dendrite-free sodium metal deposition and dissolution on the anode surface is key to developing anode-less sodium batteries, the next generation of SIBs with energy densities comparable to those of LIBs. In anode-less systems, sodium ions not only intercalate into the anode's structure but also deposit on its surface, thereby multiplying the specific capacity. Here, we evaluate state-of-the-art hard carbon (HC) used in traditional SIBs as a potential anode material for anode-less sodium batteries. We present comprehensive research on sodium-ion/metal storage, depending on the type of carbon anode material, particle size and morphology of hard carbons, and the electrolyte and additives used. Half-cells with microspherical HC and a fluoroethylene carbonate-based electrolyte operated for over 3000 h, yielding an average discharge capacity of 550 mAh g−1, nearly twice that of HC in classic SIBs. Anode-less Na3V2(PO4)3||HC full cells demonstrated up to 25 % higher energy density and working potential compared to traditional full cells.

Cyclosulfate additive inhibits Li dendrite disorder growth to achieve stable cycles of Li metal battery

ABSTRACT The high reactivity of lithium metal leads to the uncontrolled growth of lithium dendrites during the charging and discharging process of lithium metal batteries, which results in the poor cycle performance of batteries. In this paper, we innovatively utilized 1, 3-propanediol cyclic sulfate (PCS) as an additive to successfully construct a smooth and dense SEI layer containing sulfur element on the lithium metal anode surface. Under the action of PCS, the cells show excellent performance. After 200 cycles, cells with baseline electrolyte (BE) + 1 wt.% PCS still has a high capacity of of 148mAh g−1 and 81.38% capacity retention compared with cells with BE. In-situ optical microscopy is pioneeringly applied to showcase the generation and growth of lithium dendrites which showed that PCS participated in the formation of the SEI layer, indicating that this optimized SEI layer has better conductivity of Li+ and chemical stability, thus inhibiting malignant lithium deposition and electrolyte decomposition above the lithium metal anode.

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.

Exploring the Mechanisms of LiNiO2 Cathode Degradation by the Electrolyte Interfacial Deprotonation Reaction.

Nickel-rich layered oxides stand as ideal cathode candidates for high specific capacity and energy density next-generation lithium-ion batteries. However, increasing the Ni content significantly exacerbates structural degradation under high operating voltage, which greatly restricts large-scale commercialization. While strategies are being developed to improve cathode material stability, little is known about the effects of electrolyte-electrode interaction on the structural changes of cathode materials. Here, using LiNiO2 in contact with electrolytes with different proton-generating levels as model systems, we present a holistic picture of proton-induced structural degradation of LiNiO2. Through ab initio molecular dynamics calculations based on density functional theory, we investigated the mechanisms of electrolyte deprotonation, protonation-induced Ni dissolution, and cathode degradation and the impacts of dissolved Ni on the Li metal anode surfaces. We show that the proton-transfer reaction from electrolytes to cathode surfaces leads to dissolution of Ni cations in the form of NiOOHx, which stimulates cation mixing and oxygen loss in the lattice accelerating its layered-spinel-rock-salt phase transition. Migration of dissolved Ni2+ ions to the anode side causes their reduction into the metallic state and surface deposition. This work reveals that interactions between the electrolyte and cathode that result in protonation can be a dominant factor for the structural stability of Ni-rich cathodes. Considering this factor in electrolyte design should be of benefit for the development of future batteries.

Magnetic, conductive nanoparticles as building blocks for steerable micropillar-structured anodic biofilms

In bioelectrochemical systems (BES), biofilm formation and architecture are of crucial importance, especially for flow-through applications. The interface between electroactive microorganisms and the electrode surface plays an important and often limiting role, as the available surface area influences current generation, especially for poor biofilm forming organisms. To overcome the limitation of the available electrode surface, nanoparticles (NPs) with a magnetic iron core and a conductive, hydrophobic carbon shell were used as building blocks to form conductive, magnetic micropillars on the anode surface. The formation of this dynamic three-dimensional electrode architecture was monitored and quantified in situ using optical coherence tomography (OCT) in conjunction with microfluidic BES systems. By cyclic voltammetry the assembled three-dimensional anode extensions were found to be electrically conductive and increased the available electroactive surface area. The NPs were used as controllable carriers for the electroactive model organisms Shewanella oneidensis and Geobacter sulfurreducens, resulting in a 5-fold increase in steady-state current density for S. oneidensis, which could be increased 22-fold when combined with Poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) aggregates. In the case of G. sulfurreducens, the steady-state current density was not increased, but was achieved four times faster. The study presents a controllable, scalable and easy-to-use method to increase the electrode surface area in existing BES by applying a magnetic field and adding conductive magnetic NPs. These findings can most likely also be transferred to other electroactive microorganisms.

In Situ Forming Asymmetric Gel Polymer Electrolyte Enhances the Performance of High-Voltage Lithium Metal Batteries.

With the rapid evolution of electric vehicle technology, concerns regarding range anxiety and safety have become increasingly pronounced. Battery systems with high specific energy and enhanced security, featuring ternary cathodes paired with lithium (Li) metal anodes, are poised to emerge as next-generation electrochemical devices. However, the asymmetric configuration of the battery structure, characterized by the robust oxidative behavior of the ternary cathodes juxtaposed with the vigorous reductive activity of the Li metal anodes, imposes elevated requisites for the electrolytes. Herein, a well-designed gel polymer electrolyte with asymmetric structure was successfully prepared based on the Ritter reaction of cyanoethyl poly(vinyl alcohol) (PVA-CN) and cationic ring-opening polymerization of s-Trioxane. With the aid of the sieving effect of separator, the in situ asymmetric gel polymer electrolyte has good compatibility with both the high-voltage cathodes and Li anodes. The amide groups generated by PVA-CN after the Ritter reaction and additional cyano groups can tolerate high voltages up to 5.1 V, matching with ternary cathodes without any challenges. The functional amide and cyano groups participate in the formation of the cathode electrolyte interface and stabilize the cathode structure. Meanwhile, the in situ formed ether-based polyformaldehyde electrolyte is beneficial for promoting uniform Li deposition on anode surfaces. Li-Li symmetric cells demonstrate sustained stability over 2000 h of cycling at a current density of 1 mA cm-2 for 1 mAh cm-2. Furthermore, the capacity retention rate of Li(Ni0.6Mn0.2Co0.2)O2-Li cells with 0.5 C cycling after 300 cycles is 92.2%, demonstrating excellent cycle stability. The electrolyte preparation strategy provides a strategy for the progress of high-performance electrolytes and promotes the rapid development of high-energy-density Li metal batteries.

Customizing H2O‐Poor Electric Double Layer and Boosting Texture Exposure of Zn (101) Plane towards Super‐High Areal Capacity Zinc Metal Batteries

The catastrophic dendrite hyperplasia and parasitic reactions severely impede the future deployment of aqueous Zn‐ion batteries. Controlling zinc orientation growth is considered to be an effective method to overcome the aforementioned concerns, especially for regulating the (002) plane of deposited Zn. Unfortunately, Zn (002) texture is difficult to obtain stable cycling under high deposition capacity resulting from its large lattice distortion and nonuniform distribution in electric field. Herein, different from traditional cognition, a crystallization orientation regulation tactic is proposed to boost Zn (101) texture exposure and inhibit zinc dendrite proliferation during plating/stripping. Experimental results and theoretical calculations demonstrate the malate molecules preferentially adsorb on the Zn (002) facet, leading to the texture exposure of distinctive Zn (101) plane. Meanwhile, the –COOH and –OH groups of malate molecules exhibit strong adsorption on the Zn anode surface and chelate with Zn2+, achieving H2O‐poor electrical double layer. Very impressively, the multifunctional malate additive enlists zinc anode to survive for 600 h under a harsh condition of 15 mAh cm−2/15 mAh cm−2. Moreover, the symmetric cell harvests highly‐reversible cycling life of 6600 h at 5 mA cm−2/1.25 mAh cm−2, remarkably outperforming the ZnSO4 electrolyte. The assembled Zn//MnO2 full cells also demonstrate prominent electrochemical reversibility.

Customizing H2O-Poor Electric Double Layer and Boosting Texture Exposure of Zn (101) Plane towards Super-High Areal Capacity Zinc Metal Batteries.

The catastrophic dendrite hyperplasia and parasitic reactions severely impede the future deployment of aqueous Zn-ion batteries. Controlling zinc orientation growth is considered to be an effective method to overcome the aforementioned concerns, especially for regulating the (002) plane of deposited Zn. Unfortunately, Zn (002) texture is difficult to obtain stable cycling under high deposition capacity resulting from its large lattice distortion and nonuniform distribution in electric field. Herein, different from traditional cognition, a crystallization orientation regulation tactic is proposed to boost Zn (101) texture exposure and inhibit zinc dendrite proliferation during plating/stripping. Experimental results and theoretical calculations demonstrate the malate molecules preferentially adsorb on the Zn (002) facet, leading to the texture exposure of distinctive Zn (101) plane. Meanwhile, the -COOH and -OH groups of malate molecules exhibit strong adsorption on the Zn anode surface and chelate with Zn2+, achievingH2O-poorelectrical double layer. Very impressively, the multifunctional malate additive enlists zinc anode to survive for 600 h under a harsh condition of 15 mAh cm-2/15 mAh cm-2. Moreover, the symmetric cell harvests highly-reversible cycling life of 6600 h at 5 mA cm-2/1.25 mAh cm-2, remarkably outperforming the ZnSO4 electrolyte. The assembled Zn//MnO2 full cells also demonstrate prominent electrochemical reversibility.

Dual-phase interface engineering via parallel modulation strategy for highly reversible Zn metal batteries

The reversibility and stability of aqueous Zn metal batteries (AZMBs) are largely limited by Zn dendrites and interfacial parasitic reactions. Herein, we propose a parallel modulation strategy to boost the reversibility of the Zn anode by introducing N,N,N’,N’-tetramethylchloroformamidinium hexafluorophosphate (TCFH) as an additive in the electrolyte. TCFH is composed of PF6− and TN+ with opposite charges. PF6− can spontaneously induce the in-situ generation of ZnF2 solid electrolyte interface (SEI) on the anode, which can improve the transport kinetics of Zn2+ at the interface, thus promoting the rapid and uniform deposition of Zn as well as inhibiting the growth of dendrites. In addition, TN+ is enriched at the anode surface during Zn deposition through the anchoring effect, which brings a reconfiguration of the ion/molecule distribution. The anchored-TN+ reduces the concentrations of H2O and SO42−, sufficiently restraining the parasitic reaction. Thanks to the dual-phase interface engineering constructed of PF6− and TN+ in parallel, the symmetric cell with the proposed electrolyte survives long cycling stability over 750 h at 20 mA cm−2, 10 mAh cm−2. This study offers a distinct viewpoint to the multidimensional optimization of Zn anodes for high-performance AZMBs.

In-situ construction of high-performance artificial solid electrolyte interface layer on anode surfaces for anode-free lithium metal batteries

The electrochemical performance of lithium metal batteries (LMBs) was hampered by the uncontrolled growth of lithium (Li) dendrites. To address this issue, the extensive application of artificial solid electrolyte interphase (SEI) coatings on anode surfaces emerged as an effective solution. Electrospinning, as an innovative technique for fabricating artificial SEI layers on the surface of copper (Cu) foil, effectively mitigated Li volume strain during cycling. In this study, an electrospun organic–inorganic composite nanofiber membrane was in-situ fabricated on Cu foil, serving as an artificial SEI layer (CuWs) for anode-free LMBs (AF-LMBs) to enhance battery performance. Lithiophilic polyvinylpyrrolidone was used as the polymer matrix, and Cu nitrate served as the inorganic functional particles capable of in-situ redox reactions. The CuWs with their three-dimensional (3D) network structure accommodated electrode volume changes and suppressed Li dendrite growth during Li deposition and stripping. Additionally, CuWs facilitated the in-situ generation of Li nitrate (LiNO3), which helped stabilize SEI layer and enhance Li utilization. The release sites of LiNO3 on the nanofibers enabled the in-situ reduction of metallic Cu, providing nucleation sites for Li deposition and forming the 3D ion–electron hybrid conductive networks. This CuWs layer reduced interfacial resistance and nucleation barriers, promoting uniform Li+ distribution on the anode surface. Li-Cu cells incorporating CuWs exhibited remarkable cycling stability, enduring over 460 cycles at 1.0 mA cm−2 and 1.0 mAh cm−2 with an average Coulombic efficiency of over 98.6 %. In Li-poor cells, the LFP|PE|CuWs achieved stable cycling for more than 30 cycles at 1.0 C, with a capacity retention rate of 92.0 %. These findings demonstrated that the CuWs membrane significantly enhanced the electrochemical performance of Li-poor cells and provided a novel artificial SEI protective strategy for advanced AF-LMBs with high energy density.

Dual-functions of the carbon-confined oxygen on the capacitance and cycle stability enhancements of Zn-ion capacitors

Zinc-ion capacitors (ZICs) are promising energy storage devices due to their balance between the energy and power densities inherited from Zn-ion batteries and supercapacitors, respectively. However, the low specific capacitance of carbon cathode materials and the dendrite growth on Zn anode have set fatal drawbacks to their energy density and cycle stability. Herein, we demonstrate that, in 1 M Zn(CF3SO3)2/DMF (N, N-dimethylformamide) electrolyte, confining oxygen in carbon cathode materials via high-energy ball milling can synergistically introduce additional pseudocapacitance on the cathode side while suppressing the dendrite growth on Zn anode side, which jointly lead to high energy density (94 Wh kg−1 at 448 W kg−1) and long cycle stability of ZICs. The hydroxyl group in carbon cathode can be transformed to C—O—Zn together with the release of protons during the initial discharge, which in turn stimulates the defluorination of CF3SO3− anions and formation of ZnF2 on both cathode and anode. The ZnF2 formed on the surface of the Zn anode suppresses the dendrite growth by regulating the Zn2+ deposition/stripping in a reticular structure, resulting in the excellent cycle stability. This work provides a facile strategy to rationally design and construct high energy and stable ZICs through engineering the oxygen-bearing functional groups in carbon cathode materials.

Ruddlesden-Popper perovskite anode with high sulfur tolerance and electrochemical activity for solid oxide fuel cells

Solid oxide fuel cells (SOFCs) are regarded as attractive electrochemical energy conversion devices owing to their exceptional efficiencies and superb fuel flexibility. However, their widespread implementations are remarkably restricted by the inferior sulfur tolerance of state-of-the-art nickel-based cermet anodes under practical conditions. Herein, a layered NaLaTiO4 (NLTO) perovskite oxide with Ruddlesden-Popper structure is designed as a new anode for SOFCs operating on sulfur-containing fuels. After impregnating NLTO into a samaria-doped ceria (SDC) scaffold, such impregnated nanocomposite anode exhibits high electrochemical activity, sulfur tolerance and stability in H2S-containing fuels due to the polar layered structure, abundant oxygen vacancies, superior surface basicity and water storage capability, leading to the efficient removal of the deposited/adsorbed sulfur on the surface of this nanocomposite anode. The electrochemical activity of the NLTO-based composite anode for fuel oxidation is further improved by adding nickel nanoparticles through impregnation, showing enhanced power outputs and considerable operational stability in H2S-containing fuels. This study provides a new, high-performing and sulfur-resistant anode for SOFCs, which may promote the commercialization of this technology.

Achieving Dendrite-Free Zinc Deposition by Large-Size Anion-Reinforced Solvated Structures for Highly Reversible Zinc Anode

The electrochemical instability of zinc anode caused by surface side reactions and irregular zinc deposition severely hinders the practical application of aqueous zinc ion batteries (AZIBs). In this work, diethylenetriaminepentaacetic acid, pentasodium salt (DTPA) was used as a novel electrolyte additive to modulate the electrochemical stability of Zn anode. The DTPA anion can strongly coordinate with Zn2+, thus enabling the formation of a unique large-size anion-enhanced solvation structure of electrolyte. In this, not only the generation of by-products on Zn anode can be effectively inhibited, but more importantly, the deposition kinetics of Zn2+ can be well regulated to induce even and stable zinc deposition. In addition, DTPA is more prone to chemically adsorbed on the surface of Zn anode than H2O, contributing to the resistance of electrochemical corrosion. Synergistically, the Zn anode demonstrates excellent cycling stability (3850 h at 1 mA cm−2, 1 mAh cm−2, and 500 h at 10 mA cm−2, 10 mAh cm−2), enhanced coulombic efficiency (99.83% upon 3500 cycles at 5 mA cm−2, 1 mAh cm−2), and high reversibility of 1050 h even at a stringent discharge depth of 80%. Particularly, the full cell assembled with NaV3O8·1.5H2O (NaVO) cathode can also operate stably for 1800 cycles at 2 A g−1 with a high capacity retain of 90.8%. This work may pave a new route to achieve high-performance AZIBs by regulating the deposition process of Zn2+ based on large-size anion-enhanced solvation structure of electrolyte.

Zincophilic Nanospheres Assembled as Solid-Electrolyte Interphase on Zn Metal Anodes for Reversible High-rate Zn-Ion Storage.

Aqueous Zn-ion batteries (ZIBs) are considered to be one of the most promising energy storage devices in the post-lithium-ion era with fast ionic conductivity, safety, and low cost. However, excessive accumulation of zinc dendrites will fracture and produce dead zinc, resulting in the unsatisfied utilization rate of Zn anodes, which greatly restricts the lifespan of the battery and reduces the reversibility. In this paper, by constructing a protective layer of ZnSnO3 hollow nanospheres in situ growth on the surface of the Zn anode, more zincophilic sites are established on the electrode surface. It demonstrates that uniform deposition of Zn ions by deepening the binding energy with Zn ion and its unique hollow structure shortens the diffusion distance of Zn ions and enhances the reaction kinetics. The assembled Zn-ion hybrid supercapacitor (ZHSC) of ZnSnO3@Zn//AC achieved a long-term lifespan with 4000 cycles at a current density of 10mAcm-2 with a Coulombic efficiency of 99.31% and capacity retention of 79.6%. This work offers a new path for advanced Zn anodes interphase supporting the long cycle life with large capacities and improving electrochemical reversibility.

Functionalized fillers as “ions relay stations” enabling Li+ ordered transport in quasi-solid electrolytes for high-stability lithium metal batteries

Quasi–solid–state lithium–metal batteries (QSLMBs) are promising candidates for next–generation battery systems due to their high energy density and enhanced safety. However, their practical application has been hindered by low ionic conductivity and the growth of lithium dendrites. To achieve ordered transport of Li+ ions in quasi–solid electrolytes (QSEs), improve ionic conductivity, and homogenize Li+ fluxes on the surface of the lithium metal anode (LMA), we propose a novel method. This method involves constructing “ion relay stations” in QSEs by introducing cyano–functionalized boron nitride nanosheets into pentaerythritol tetraacrylate (PETEA) –based polymer electrolytes. The functionalized boron nitride nanosheets promote the dissociation of lithium salts through ion–dipole interactions, optimizing the solvated structure to facilitate the orderly transport of Li+ ions, resulting in an ionic conductivity of 2.5 × 10−3 S cm−1 at 30 °C. Notably, this strategy regulates the Li+ distribution on the surface of the LMA, effectively inhibiting the growth of lithium dendrites. Li||Li symmetrical cells using this type of electrolyte maintain stability for over 2000 h at 2 mA cm−2 and 2 mAh cm−2. Additionally, with a high LiNi0.8Co0.1Mn0.1O2 (NCM811) loading of 8.5 mg cm−2, the cells exhibit excellent cycling performance, retaining a high capacity after 400 cycles. This innovative QSE design strategy represents a significant advancement towards the development of high–performance QSLMBs.

A Clay-Based Quasi-Solid-State electrolyte with high cation selective channels for High-Performance aqueous Zinc-Ion batteries

A clay-based quasi-solid-state electrolyte was prepared using dimethyl sulfoxide (DMSO) intercalated kaolinite as the raw material to suppress the adverse effects of free water molecules on aqueous zinc-ion batteries (AZIBs). Based on the inherent water absorption and retention properties of clay kaolinite, as well as the interlayer modification, this clay-based quasi-solid-state electrolyte not only achieved a low water content but also exhibited a strong water binding effect, which restricted the HER and side reactions involving water participation. Furthermore, the intercalation of DMSO increased the number of negative charges on the surface of kaolinite, resulting in the formation of a continuous spatial electrostatic field area around the kaolinite particles, which played a role in cation selectivity. The ionic transference number of the quasi-solid-state electrolyte reached 0.91. Additionally, the intercalation of DMSO broadened the interlayer ionic transport channels of kaolinite, further enhancing the transport efficiency of Zn2+ in the quasi-solid-state electrolyte, achieving uniform deposition of Zn2+ on the surface of the Zn anode, and suppressing dendrite growth to maintain a stable quasi-solid-state electrolyte/Zn anode interface. Zn||MnO2 battery assembled with this electrolyte demonstrated a discharge specific capacity of 301 mAh/g at a current density of 60 mA g−1. The Zn||MnO2 battery could be stably cycled for 1000 cycles at a current density of 150 mA g−1, and after 1000 cycles, the battery still maintained a discharge specific capacity of 248.2 mAh/g with a capacity retention rate of 84.8 %, showing excellent capacity performance and cycle stability. The Zn||MnO2 pouch battery could still provide stable power under heavy pressure, bending, and continuous tapping and had the potential for use in flexible batteries.

Li2CO3/LiF-Rich Solid Electrolyte Interface Stabilized Lithium Metal Anodes for Durable Li-CO2 Batteries

Lithium carbon dioxide (Li-CO2) batteries are considered a promising next-generation energy storage device due to their high theoretical energy density and potential carbon neutralization. Despite numerous iterative advancements in cathode catalysts for Li-CO2 batteries, the cycling stability still to be hindered by the growth of lithium dendrites during cycling, primarily due to uneven deposition and the side reaction of sufficient CO2 with the Li metal anode. In this work, bisalt electrolyte (BE) consisting of LiPF6 and LiTFSI is used as a localized anode surface stabilizer to achieve durable Li-CO2 batteries. The introduction of PF6− promotes the decomposition and reduction of TFSI−, leading to the formation of LiF-rich inorganic SEI (Li2CO3/LiF-rich) with enhanced Li+ affinity and good electronic insulating properties. This effectively inhibits lithium dendrite formation while also insulating CO2 and electrolytes from contacting the lithium anode. Consequently, the Li symmetric battery incorporating the novel BE exhibits a long cycling life of 912 hours (∼3.8 times of the cell with a single-salt electrolyte (SE)). The BE based Li-CO2 battery achieves an ultra-long cyclelife of 2720 hours (∼2.6 times of SE battery) and outstanding rate capability. In addition, the assembled belt-shaped Li-CO2 batteries could stably power a digital watch for 1267 hours.

Halogenated Solvation Structure and Preferred Zn (002) Deposition via Trace Additive towards High Reversibility for Aqueous Zinc-Ion Batteries

Tremendous progress has been achieved in cathode materials for aqueous zinc-ion batteries (AZIBs), however their practical applications are hindered by the poor cycling stability of Zn anode. Herein, amphiphilic choline bromine (ChBr) is introduced as additive into highly-concentrated ZnSO4 aqueous electrolyte, which not only regulates the traditional Zn2+ solvation structure but also establishes an electrostatic shielding layer at electrolyte-anode interface. Compared to the pristine 3 M ZnSO4 electrolyte, ChBr-modified ZnSO4 electrolyte (ZSO-ChBr) is proven effective in promoting the reversibility of zinc plating/stripping and the preferred growth of Zn (002) plane, as well as suppressing the hydrogen evolution and side reactions on Zn anode surface. As a result, Zn||Zn symmetric cell in optimal ZSO-ChBr electrolyte could harvest a remarkable lifespan over 6000 h at 5 mA cm−2 and 1 mAh cm−2, besides a highly-reversible zinc plating/stripping process over 1500 cycles was achieved in Zn||Cu asymmetric cell. Moreover, the Zn||MnO2 full cell could exhibit an excellent rate capability and the cycling stability with a capacity retention of 80% after 400 cycles. This work provides an integrated strategy of electrolyte engineering to elevate the desolvation kinetics of Zn2+ at anode-electrolyte interface and enhance the cycling stability of Zn anode, effectively improving the electrochemical performances of aqueous zinc-ion batteries (AZIBs) and promoting the development of various energy storage systems.