锂硒电池ZIF-L衍生氮掺杂碳纳米片/碳布自支撑电极的电化学性能研究OA北大核心CSTPCD

Selenium(Se)is considered as a new generation energy storage material of lithium-selenium(Li-Se)battery due to its high volume specific capacity(3253 mAh·cm-3)and high electronic conductivity(1 × 10 5 S·m-1).To address the problems of volume expansion,fast capacity decay,and low utilization of active materials during its charging-discharging process,a ZIF-L derived nitrogen-doped nanosheets/selenium(Se@NC/CC)flexible self-supported composite electrode is designed in this study for lithium-selenium battery by growing two-dimensional zinc-based metallic organic framework(ZIF-L)on carbon cloth(CC).The rich microporous structure in the nitrogen-doped carbon nanosheets can effectively alleviate the volume expansion during the reaction process,and the doping of heteroatoms N helps to adsorb Li2Se and reduce the loss of active substances.In particular,it is found that there is strong chemical bonding between Se and C in the Se@NC/CC electrode,which also helps to reduce the loss of active materials and improve the performance.Electrochemical results show that the initial discharge specific capacity of the Se@NC/CC electrode is 574 mAh·g-1 at a current density of 0.5C(1.0C=675 mAh·g-1),demonstrating a high initial discharge specific capacity.At a current density of 2.0C,the initial discharge specific capacity is 453.3 mAh·g-1,which maintains at 406.2 mAh·g-1after cycling for 500 cycles and it also displays excellent rate performance compared to literature.Such a flexible self-supported selenium cathode designed in this study provides a new research route on the design of selenium host materials for advanced alkali metal-selenium batteries.