设计和制备具有优异稳定性和高活性的催化剂对于提高锂-氧气电池的性能至关重要.由于其可调节的结构及促进氧还原反应和析氧反应动力学的有效性,异质结构催化剂引起了广泛的研究兴趣.在这项工作中,CuCo_(2)S_(4)/CoS_(1.097)多元金属硫...设计和制备具有优异稳定性和高活性的催化剂对于提高锂-氧气电池的性能至关重要.由于其可调节的结构及促进氧还原反应和析氧反应动力学的有效性,异质结构催化剂引起了广泛的研究兴趣.在这项工作中,CuCo_(2)S_(4)/CoS_(1.097)多元金属硫化物被证明是锂-氧气电池氧电极反应的有效电催化剂.密度泛函理论计算表明,CuCo_(2)S_(4)/CoS_(1.097)的电子结构在异相界面处受到调控,有利于优化氧电极反应过程中间体的吸附,最终加速氧电极反应动力学.实验结果表明,基于CuCo_(2)S_(4)/CoS_(1.097)的锂-氧气电池在100 m A g^(-1)下具有26,727.8 m A h g^(-1)的高比容量和超过267次循环的出色耐久性.该工作为锂-氧气电池高性能正极材料的设计和构造提供了新视角.展开更多
The development of cationic vacancies has been extensively examined as an effective strategy to improve the activity of electrocatalysts.However,it is a challenge to effectively introduce cationic vacancies on the mat...The development of cationic vacancies has been extensively examined as an effective strategy to improve the activity of electrocatalysts.However,it is a challenge to effectively introduce cationic vacancies on the material surface.Their specific effects on the electrochemical performance of lithium-oxygen(Li-O_(2))batteries are rarely reported.In this work,vanadium pentoxide with abundant vanadium vacancies(V_(2-x)O_(5))is in situ prepared on the V_(2)C MXene(V_(2-x)O_(5)@V_(2)C MXene)surface,and their bifunctional catalytic activity toward the oxygen electrode reaction in Li-O_(2)batteries is systematically examined.The results show that the V_(2-x)O_(5)@V_(2)C MXene-based Li-O_(2)battery exhibits excellent performance.It delivers a high energy efficiency of 83.4%at 100 mA g^(-1) and excellent cycling performance of more than 500 cycles.Furthermore,density functional theory calculations confirm that the presence of cationic vanadium vacancies can provide abundant active sites to reduce the reaction barrier and optimize the adsorption of reactants,increasing the oxygen electrode reactions in the Li-O_(2)battery.This work provides a meaningful view that modulating the electronic structure by creating cationic metal vacancies can improve the electrocatalytic activity of transition metal oxides.展开更多
基金supported by the National Natural Science Foundation of China(21905033 and 52271201)the Science and Technology Department of Sichuan Province(2022YFG0100)the State Key Laboratory of Vanadium and Titanium Resources Comprehensive Utilization(2020P4FZG02A)。
文摘设计和制备具有优异稳定性和高活性的催化剂对于提高锂-氧气电池的性能至关重要.由于其可调节的结构及促进氧还原反应和析氧反应动力学的有效性,异质结构催化剂引起了广泛的研究兴趣.在这项工作中,CuCo_(2)S_(4)/CoS_(1.097)多元金属硫化物被证明是锂-氧气电池氧电极反应的有效电催化剂.密度泛函理论计算表明,CuCo_(2)S_(4)/CoS_(1.097)的电子结构在异相界面处受到调控,有利于优化氧电极反应过程中间体的吸附,最终加速氧电极反应动力学.实验结果表明,基于CuCo_(2)S_(4)/CoS_(1.097)的锂-氧气电池在100 m A g^(-1)下具有26,727.8 m A h g^(-1)的高比容量和超过267次循环的出色耐久性.该工作为锂-氧气电池高性能正极材料的设计和构造提供了新视角.
基金supported by the National Natural Science Foundation of China(21905033)the Science and Technology Department of Sichuan Province(2019YJ0503)the State Key Laboratory of Vanadium and Titanium Resources Comprehensive Utilization(2020P4FZG02A)。
文摘The development of cationic vacancies has been extensively examined as an effective strategy to improve the activity of electrocatalysts.However,it is a challenge to effectively introduce cationic vacancies on the material surface.Their specific effects on the electrochemical performance of lithium-oxygen(Li-O_(2))batteries are rarely reported.In this work,vanadium pentoxide with abundant vanadium vacancies(V_(2-x)O_(5))is in situ prepared on the V_(2)C MXene(V_(2-x)O_(5)@V_(2)C MXene)surface,and their bifunctional catalytic activity toward the oxygen electrode reaction in Li-O_(2)batteries is systematically examined.The results show that the V_(2-x)O_(5)@V_(2)C MXene-based Li-O_(2)battery exhibits excellent performance.It delivers a high energy efficiency of 83.4%at 100 mA g^(-1) and excellent cycling performance of more than 500 cycles.Furthermore,density functional theory calculations confirm that the presence of cationic vanadium vacancies can provide abundant active sites to reduce the reaction barrier and optimize the adsorption of reactants,increasing the oxygen electrode reactions in the Li-O_(2)battery.This work provides a meaningful view that modulating the electronic structure by creating cationic metal vacancies can improve the electrocatalytic activity of transition metal oxides.
