Electrochemical behaviors and electrochemical performances of lithium-selenium battery using selenium/carbon as cathode in different electrolytes

Abstract

Lithium-selenium (Li-Se) battery with high theoretical volume energy density (3253 mA h cm -3 ) is a very promising next-generation energy storge system, however, it still faces the problems of polyselenide generation and dissolution, as well as low active material utilization. Herein, electrochemical performance of Se/carbon cathode for Li-Se battery in three kinds of electrolytes, e.g. , ether-based, ester-based and solvate electrolyte, were studied to discuss the possibility of capacity as well as cycle life regulation. The Se/carbon cathode showed significant overcharging in the ether-based electrolyte owing to a severe polyselenide shuttle problem, and displayed a moderate electrochemical performance in ester-based electrolyte. Due to the no free solvent property of the solvate electrolyte, the Se/carbon cathode obtained extremely high Se utilization with an initial specific capacity of 621 mA h g -1 and a reversible capacity of 516 mA h g -1 at 1.0 C current rate after 200 cycles.