Lithium-sulfur(Li-S)batteries hold great promise for the next generation of high energy density systems.However,sluggish sulfur conversion and the shuttle effect of polysulfides severely limit their commercial applica...Lithium-sulfur(Li-S)batteries hold great promise for the next generation of high energy density systems.However,sluggish sulfur conversion and the shuttle effect of polysulfides severely limit their commercial applications.Herein,a multifunctional covalent organic framework(Ni-COF)with extendedπ-d conjugated structure was synthesized and used for separator modification to overcome the obstacles in Li-S batteries.Ni-COF inherits the advantages of both COFs and conductive metal-organic frameworks,while compensating for their respective disadvantages.The abundant oxygen-containing groups in Ni-COF act as chemical adsorption sites to inhibit the shuttle effect of polysulfides.The designedπ-d conjugated structure enhances electrical conductivity and provides high-density metal catalytic sites,thereby facilitating the conversion of polysulfides and enhancing the reaction kinetics of Li-S batteries.Consequently,the Li-S batteries with Ni-COF@PP separator exhibit remarkable rate performance of 719 mA h g^(-1)at 4 C,along with a low attenuation rate of 0.087%per cycle over 300 cycles at 1 C.This study proposes a novel strategy for the rational design of COFs in Li-S batteries.展开更多
基金supported by the National Natural Science Foundation of China(22209155 and 52201283)China Postdoctoral Science Foundation(2024M752941,2022TQ0291,and 2022M712869)+1 种基金Henan Postdoctoral Science Foundation(HN2024059)Frontier Exploration Projects of Longmen Laboratory(LMQYTSKT021).
文摘Lithium-sulfur(Li-S)batteries hold great promise for the next generation of high energy density systems.However,sluggish sulfur conversion and the shuttle effect of polysulfides severely limit their commercial applications.Herein,a multifunctional covalent organic framework(Ni-COF)with extendedπ-d conjugated structure was synthesized and used for separator modification to overcome the obstacles in Li-S batteries.Ni-COF inherits the advantages of both COFs and conductive metal-organic frameworks,while compensating for their respective disadvantages.The abundant oxygen-containing groups in Ni-COF act as chemical adsorption sites to inhibit the shuttle effect of polysulfides.The designedπ-d conjugated structure enhances electrical conductivity and provides high-density metal catalytic sites,thereby facilitating the conversion of polysulfides and enhancing the reaction kinetics of Li-S batteries.Consequently,the Li-S batteries with Ni-COF@PP separator exhibit remarkable rate performance of 719 mA h g^(-1)at 4 C,along with a low attenuation rate of 0.087%per cycle over 300 cycles at 1 C.This study proposes a novel strategy for the rational design of COFs in Li-S batteries.
