Covalent organic frameworks(COFs)are promising materials for mitigating polysulfide shuttling in lithium-sulfur(Li-S)batteries,but enhancing their ability to convert polysulfides across a wide temperature range remain...Covalent organic frameworks(COFs)are promising materials for mitigating polysulfide shuttling in lithium-sulfur(Li-S)batteries,but enhancing their ability to convert polysulfides across a wide temperature range remains a challenge,Herein,we introduce a redox-active COF(RaCOF)that functions as both a physical barrier and a kinetic enhancer to improve the temperature adaptability of Li-S batteries,The RaCOF constructed from redox-active anthraquinone units accelerates polysulfide conversion kinetics through reversible C=O/C-OLi transformations within a voltage range of 1,7 to 2.8 V(vs.Li^(+)/Li),optimizing sulfur redox reactions in ether-based electrolytes.Unlike conventional COFs,RaCOF provides bidentate trapping of polysulfides,increasing binding energy and facilitating more effective polysulfide management.In-situ XRD and ToF-SIMS analyses confirm that RaCOF enhances polysulfide adsorption and promotes the transformation of lithium sulfide(Li_(2)S),leading to better sulfur cathode reutilization.Consequently,RaCOF-modified Li-S batteries demonstrate low self-discharge(4.0%decay over a 7-day rest),excellent wide-temperature performance(stable from-10 to+60℃),and high-rate cycling stability(94%capacity retention over 500 cycles at 5.0 C).This work offers valuable insights for designing COF structures aimed at achieving temperature-adaptive performance in rechargeable batteries.展开更多
基金funding supporting from the National Natural Science Foundation of China(22309003,22379001)the Natural Science Research Project of Anhui Province Education Department(2023AH051119)+3 种基金the open project funding from Shanghai Key Laboratory of Multi phase Materials Chemical Engineering(MMCE2024001)the National Key Research and Development Program of China(2022YFB2402201)the Shanghai Pilot Program for Basic Research-Hehai University 21TQ1400100(21TQ009)the Fundamental Research Funds for the Central Universities(20720220010).
文摘Covalent organic frameworks(COFs)are promising materials for mitigating polysulfide shuttling in lithium-sulfur(Li-S)batteries,but enhancing their ability to convert polysulfides across a wide temperature range remains a challenge,Herein,we introduce a redox-active COF(RaCOF)that functions as both a physical barrier and a kinetic enhancer to improve the temperature adaptability of Li-S batteries,The RaCOF constructed from redox-active anthraquinone units accelerates polysulfide conversion kinetics through reversible C=O/C-OLi transformations within a voltage range of 1,7 to 2.8 V(vs.Li^(+)/Li),optimizing sulfur redox reactions in ether-based electrolytes.Unlike conventional COFs,RaCOF provides bidentate trapping of polysulfides,increasing binding energy and facilitating more effective polysulfide management.In-situ XRD and ToF-SIMS analyses confirm that RaCOF enhances polysulfide adsorption and promotes the transformation of lithium sulfide(Li_(2)S),leading to better sulfur cathode reutilization.Consequently,RaCOF-modified Li-S batteries demonstrate low self-discharge(4.0%decay over a 7-day rest),excellent wide-temperature performance(stable from-10 to+60℃),and high-rate cycling stability(94%capacity retention over 500 cycles at 5.0 C).This work offers valuable insights for designing COF structures aimed at achieving temperature-adaptive performance in rechargeable batteries.
