Advanced preparation and application of bimetallic materials in lithium-sulfur batteries:A review

Lithium-sulfur(Li-S)batteries are considered highly promising as next-generation energy storage systems due to high theoretical capacity(2600 Wh kg^(-1))and energy density(1675 mA h g^(-1))as well as the abundant natural reserves,low cost of elemental sulfur,and environmentally friendly properties.However,several challenges impede its commercialization including low conductivity of sulfur itself,the severe“shuttle effect”caused by lithium polysulfides(LiPSs)during charge–discharge processes,volume expansion effects and sluggish reaction kinetics.As a solution,polar metal particles and their compounds have been introduced as the main hosts for sulfur cathode due to their robust catalytic activity and adsorption capability,effectively suppressing the“shuttle effect”of Li PSs.Bimetallic alloys and their compounds with multi-functional properties exhibit remarkable electrochemical performance more readily when compared to single-metal materials.Well-designed bimetallic materials demonstrate larger specific surface areas and richer active sites,enabling simultaneous high adsorption capability and strong catalytic properties.The synergistic effect of the“adsorption-catalysis”sites accelerates the adsorptiondiffusion-conversion process of Li PSs,ultimately achieving a long-lasting Li-S battery.Herein,the latest progress and performance of bimetallic materials in cathodes,separators,and interlayers of Li-S batteries are systematically reviewed.Firstly,the principles and challenges of Li-S batteries are briefly analyzed.Then,various mechanisms for suppressing“shuttle effects”of Li PSs are emphasized at the microscale.Subsequently,the performance parameters of various bimetallic materials are comprehensively summarized,and some improvement strategies are proposed based on these findings.Finally,the future prospects of bimetallic materials are discussed,with the hope of providing profound insights for the rational design and manufacturing of high-performance bimetallic materials for LSBs.

Design of functionalized fluorescent ionic liquid and its application for achieving significant improvements in Al^3t detecting

Specific fluorophore was introduced into ionic liquid based on its tunability,thus a kind of novel fluorescent ionic liquid probe[P66614][HQS]was designed,synthesized and characterized.Compared with non-fluorescent HQS,ionic liquid[P66614][HQS]emitted a certain amount of fluorescence,which could be attributed to the well-delocalized frontier orbitals and its charge transfer character,as demonstrated by quantum chemical calculation.Considering the interaction of[P66614][HQS]with metal ions,the application for detecting specific substance as a chemical sensor,such as Al3+was investigated.Compared with the traditional probe HQS,significant improvements in Al^3+detecting was achieved by[P66614][HQS]with stronger binding ability,better sensitivity and selectivity.The better performance of[P66614][HQS]was contributed to the changed charge distribution,leading to the stronger binding interaction.We believe that this new fluorescent ionic liquid exhibited unique properties in detecting Al^3+in aqueous solution,which would broaden the application of ionic liquids.