Structural engineering of cathodes for improved Zn-ion batteries

Aqueous zinc-ion batteries (ZIBs) are attracting considerable attention because of their low cost,high safety and abundant anode material resources.However,the ...     

Redox-active zinc thiolates for low-cost aqueous rechargeable Zn-ion batteries

Aqueous zinc-ion batteries (AZIBs) are promising candidates for large-scale electrical energy storage due to the inexpensive, safe, and non-toxic nature of zinc. One key area that requires further development is electrode materials that store Zn²⁺ ions with high reversibility and fast kinetics. To determine the viability of low-cost organosulfur compounds as OEMs for AZIBs, we investigate how structural modification affects electrochemical performance in Zn-thiolate complexes 1 and 2. Remarkably, modification of one thiolate in 1 to sulfide in 2 reduces the voltage hysteresis from 1.04 V to 0.15 V. While 1 exhibits negligible specific capacity due to the formation of insulating DMcT polymers, 2 delivers a capacity of 107 mA h g⁻¹ with a primary discharge plateau at 1.1 V vs. Zn²⁺/Zn. Spectroscopic studies of 2 suggest a Zn²⁺ and H⁺ co-insertion mechanism with Zn²⁺ as the predominant charge carrier. Capacity fading in Zn-2 cells likely results from the formation of (i) soluble H⁺ insertion products and (ii) non-redox-active side products. Increasing electrolyte concentration and using a Nafion membrane significantly enhances the stability of 2 by suppressing H⁺ insertion. Our findings provide insight into the molecular design strategies to reduce the polarization potential and improve the cycling stability of the thiolate/disulfide redox couple in aqueous battery systems.

This study demonstrates the viability of the thiolate/disulfide redox couple in AZIB applications, and provides an in-depth study on the electrochemical mechanism of Zn-thiolates electrode materials.     

Aqueous Zn-ion batteries: Cathode materials and analysis

Reversible aqueous Zn-ion electrochemistry has revived the interest in aqueous batteries, thanks to the attractive features conferred by the energy dense metallic zinc anode and safe and inexpensive aqueous electrolytes. Ultimately, the practical development of the technology would depend significantly on the cathode hosts’ electrochemistry, which is strongly influenced by the structural and functional attributes of host materials. We introspect that here while reviewing different inorganic host chemistries and some notable findings that can potentially shape future developments. An assessment of the energy density and its relation to the inactive components of the cell is also presented. Finally, we take a critical look at the evolving ambiguity around the analysis of the charge storage mechanism and raise a few questions on mechanistic understanding and lack thereof, which are crucial to address shortcomings in the cathode performance.     

A single-ion conducting covalent organic framework for aqueous rechargeable Zn-ion batteries

Despite their potential as promising alternatives to current state-of-the-art lithium-ion batteries, aqueous rechargeable Zn-ion batteries are still far away from practical applications. Here, we present a new class of single-ion conducting electrolytes based on a zinc sulfonated covalent organic framework (TpPa-SO₃Zn_0.5) to address this challenging issue. TpPa-SO₃Zn_0.5 is synthesised to exhibit single Zn²⁺ conduction behaviour via its delocalised sulfonates that are covalently tethered to directional pores and achieve structural robustness by its β-ketoenamine linkages. Driven by these structural and physicochemical features, TpPa-SO₃Zn_0.5 improves the redox reliability of the Zn metal anode and acts as an ionomeric buffer layer for stabilising the MnO₂ cathode. Such improvements in the TpPa-SO₃Zn_0.5–electrode interfaces, along with the ion transport phenomena, enable aqueous Zn–MnO₂ batteries to exhibit long-term cyclability, demonstrating the viability of COF-mediated electrolytes for Zn-ion batteries.

A zinc sulfonated covalent organic framework is presented as a new single-ion conducting electrolyte for aqueous rechargeable Zn-ion batteries.     

Pre-constructed SEI on graphite-based interface enables long cycle stability for dual ion sodium batteries

Lithium batteries have been widely used in all over the world for its high energy density, long-term cycle stability. While the resources of lithium metal and transition metal are limited, which restrict their applications in the grid energy storage. Dual ion sodium batteries (DISBs) possess higher energy density, especially owning high power density for its higher operating voltage (> 4.5 V). Nevertheless, the poor oxidation tolerance of carbonate electrolyte and the co-intercalation of solvents accompanied with anions are main obstacles to make the DISBs commercialization. Herein, a physical barrier (artificial SEI film) is pre-constructed in the Na||graphite batteries to solve these thorny problems. With the CSMG (covered SEI on modified graphite), batteries deliver higher capacity 40 mAh/g even under the current density of 300 mA/g and the capacity retention maintains very well after 100 cycles at a high operating voltage. Moreover, the function mechanism was revealed by in-situ XRD, demonstrating that the pre-constructed SEI can effectively suppress the irreversible phase transition and exfoliation of graphite, resulting from the co-intercalation of anions. Additionally, the work voltage windows of carbonate electrolyte are significantly broadened by establishing electrode/electrolyte interphase. This method opens up an avenue for the practical application of DISBs on the grid energy storage and other fields.     

Bifunctional electrolyte regulation towards low-temperature and high-stability Zn-ion hybrid capacitor

Aqueous Zinc-based energy storage devices are considered as one of the potential candidates in future power technologies. Nevertheless, poor low temperature performance and uncontrollable Zn dendrite growth lead to the limited energy storage capability. Herein, an anti-hydrolysis, cold-resistant, economical, safe, and environmentally friendly electrolyte is developed by utilizing water, ethylene glycol(EG),and ZnCl₂ with high ionic conductivity(7.9 mS cm^-1 in glass fiber me...     

含氧空位的氟掺杂二氧化锰助力稳定锌离子电池

将无机盐NH₄F加入到MnO₂的前驱体溶液中,通过高效、简单的一步水热法制备了具有氧缺陷的F掺杂α-MnO₂纳米棒(记为F-MnO₂)。氧空位和F掺杂对提高F-MnO₂的导电性、促进离子扩散、提高倍率性能起着至关重要的作用。另外,由于F掺杂,形成了F—Mn键,这可以有效地抑制放电产物中Mn³⁺的Jahn-Teller畸变,从而提高结构的稳定性。得益于这些协同效应,组装的Zn||F-MnO₂全电池在0.5 A·g^-1下,首圈放电比容量高达274 mAh·g^-1,且具有较长的循环寿命和优异的倍率性能。同时,通过循环伏安(CV)和恒流充放电(GCD)曲线证明了F-MnO₂的储能机制为H⁺和Zn²⁺的共嵌入/脱出过程。     

Wet spinning of fiber-shaped flexible Zn-ion batteries toward wearable energy storage

High-performance flexible one-dimensional(1D) electrochemical energy storage devices are crucial for the applications of wearable electronics. Although much progress on various 1D energy storage devices has been made, challenges involving fabrication cost, scalability, and efficiency remain. Herein, a highperformance flexible all-fiber zinc-ion battery(ZIB) is fabricated using a low-cost, scalable, and efficient continuous wet-spinning method. Viscous composite inks containing cellulose nanofibe...     

Cell-nucleus structured electrolyte for low-temperature aqueous zinc batteries

Rechargeable aqueous zinc(Zn) batteries hold great promise for large-scale energy storage,but their implementation is plagued by poor Zn reversibility and unsatisfactory low-temperature performance.Herein,we design a cell-nucleus structured electrolyte by introducing low-polarity 1,2-dimethoxyethane(DME) into dilute 1 M zinc trifluoromethanesulfonate(Zn(OTf)₂) aqueous solution,which features an OTf^--rich Zn²⁺-primary solvation sheath(PSS,inner nucleus) and the DM...     

Prussian blue analogues as aqueous Zn-ion batteries electrodes: Current challenges and future perspectives

The urgency of integrating renewable energy sources in the power grid has pushed the development of aqueous metal-ion batteries because of their low cost, nontoxicity, high safety, and environmentally friendliness. Among the variety of aqueous metal-ion batteries that are currently under development, aqueous Zn-ion batteries (A-ZIBs) have recently gained a great attention because of their high specific energy and high reversibility in aqueous solutions, together with the low cost and high abundancy of the zinc. In this article, the authors intend to present an overview of the Prussian blue analogue materials, which are among the most promising materials for positive electrodes in A-ZIBs because of their easier synthesis route, reversible ion-insertion, high safety, and low toxicity, highlighting their strength points and open challenges.     

Non-solvating fluorosulfonyl carboxylate enables temperature-tolerant lithium metal batteries

Advanced electrolyte engineering is an important strategy for developing high-efficacy lithium(Li) metal batteries(LMBs). Unfortunately, the current electrolytes limit the scope for creating batteries that perform well over temperature ranges. Here, we present a new electrolyte design that uses fluorosulfonyl carboxylate as a non-solvating solvent to form difluoroxalate borate(DFOB-) anion-rich solvation sheath,to realize high-performance working of temperature-tolerant LMBs. With this optimized...     

Anti-aggregation growth and hierarchical porous carbon encapsulation enables the C@VO2 cathode with superior storage capability for aqueous zinc-ion batteries

Self-aggregation and sluggish transport kinetics of cathode materials would usually lead to the poor electrochemical performance for aqueous zinc-ion batteries (AZIBs).In this work,we report the construction of C@VO₂composite via anti-aggregation growth and hierarchical porous carbon encapsulation.Both of the morphology of composite and pore structure of carbon layer can be regulated by tuning the adding amount of glucose.When acting as cathode applied for AZIBs,the C@VO₂-3...     

High electrochemical stability of polyvinylidene fluoride (PVDF) porous membranes using phase inversion methods for lithium-ion batteries

Journal of Solid State Electrochemistry - Polyvinylidene fluoride (PVDF) porous membranes were prepared by non-solvent-induced phase separation (NIPS) method. The membranes were made by different...     

A superior catalyst for low-temperature NO reduction with NH3

Mn-Ce mixed-oxide catalyst yields nearly 100% NO conversion at 100-150 degrees C at a high space velocity of 42,000 h(-1). SO2 and H2O (at high concentrations) have only slight effects on the activity.     

Realizing high-performance Zn-ion batteries by a reduced graphene oxide block layer at room and low temperatures

Rechargeable aqueous Zn-ion batteries (ZIBs) have attracted great attention due to their costeffectiveness,high safety,and environmental friendliness.However,some issues associated with poor structural instability of cathode materials and fast self-discharge hinder the further development of ZIBs.Herein,a new configuration is introduced by placing a reduced graphene oxide film as a block layer between the separator and the V_2O_5·nH_2O cathode.This layer prevents the free diffusion of dissolved active materials to the anode and facilitates the transport of Zn ion and electrons,largely improving the cyclic stability and alleviating the self-discharge.Accordingly,the optimized battery delivers a remarkable capacity of 191 mAh g~(-1) after 500 cycles at 2 A g~(-1).Moreover,a high capacity of 106 mAh g~(-1) is achieved after 100 cycles at-20℃.The strategy proposed is expected to be applicable to other electrode systems,thus offering a new approach to circumvent the critical challenges facing aqueous batteries.     

Methods for enhancing the capacity of electrode materials in low-temperature lithium-ion batteries

Lithium-ion batteries(LIBs) have evolved into the mainstream power source of ene rgy sto rage equipment by reason of their advantages such as high energy density,high power,long cycle life and less pollution.With the expansion of their applications in deep-sea exploration,aerospace and military equipment,special working conditions have placed higher demands on the low-temperature performance of LIBs.However,at low temperatures,the severe polarization and inferior electrochemical activity of electrode materials cause the acute capacity fading upon cycling,which greatly hindered the further development of LIBs.In this review,we summarize the recent important progress of LIBs in low-temperature operations and introduce the key methods and the related action mechanisms for enhancing the capacity of the various cathode and anode materials.It aims to promote the development of high-performance electrode materials and broaden the application range of LIBs.     

A low-cost bromine-fixed additive enables a high capacity retention zinc-bromine batteries

In recent years,more and more efforts are devoting to clean energy,renewable energies in particular to achieving net zero carbon dioxide emissions[1].However,renewable energies,like solar power and wind power,are generally intermittent and random,hindering their wide application[2,3].To address this problem,there is an urgent need in effective and reliable energy storage device.     

Diluent decomposition-assisted formation of Li F-rich solid-electrolyte interfaces enables high-energy Li-metal batteries

Passivation by the inorganic-rich solid electrolyte interphase(SEI),especially the LiF-rich SEI,is highly desirable to guarantee the durable lifespan of Li metal batteries(LMBs).Here,we report a diluent with the capability to facilitate the formation of LiF-rich SEI while avoiding the excess consumption of Li salts.Dissimilar to most of reported inert diluents,heptafluoro-l-methoxypropane(HM) is firstly demonstrated to cooperate with the decomposition of anions to generate LiF-rich SEI via relea...     

Advances in sodium-ion batteries at low-temperature: Challenges and strategies

With the continuing boost in the demand for energy storage,there is an increasing requirement for batteries to be capable of operation in extreme environmental conditions.Sodium-ion batteries(SIBs) have emerged as a highly promising energy storage solution due to their promising performance over a wide range of temperatures and the abundance of sodium resources in the earth’s crust.Compared to lithiumion batteries(LIBs),although sodium ions possess a larger ionic radius,they are more easily deso...