In‐situ confining selenium within bubble – like carbon nanoshells for ultra‐stable Li−Se batteries

Abstract

AbstractLithium‐selenium (Li−Se) batteries are promising energy storage devices. However, the long‐term durability and high‐rate performance of the Se cathode have been limited by significant volume expansion and the troublesome shuttle effect of polyselenides during repeated charging/discharging processes. To revolutionize these issues, we applied a top‐down strategy through the in‐situ trapping of amorphous Se within bubble‐like carbon (BLC) frameworks, which can radically minimize the presence of surface‐absorbed Se while enhancing Se loading capacity. This ingenious technique successfully encapsulates all Se species within carbon nanoshells, creating a distinct half‐filled core‐shell structure known as Se@void@BLC. This in‐situ trapping approach ensures the efficient management of Se volume changes during repeated discharge and charge cycles. Moreover, an extraordinary Se loading capacity of up to 65.6 wt% is reached. Using the Se@void@BLC as cathode for Li−Se battery, we achieve a high initial Columbic efficiency of 84.2 %, a high reversible capacity of 585 mAh g−1, and an ultralow capacity decay of only 0.0037 % per cycle during 4000 cycles at 10 A g−1.