Taming the anchor and conversion of polyselenides with a self-reinforcing host in lithium–selenium batteries

Abstract

Energy-dense lithium–selenium (Li–Se) batteries have attracted increasing attention, while their practical application is still hindered, highly relating to the volume expansion and shuttle of Li polyselenides (LiPSes). Herein, a concurrent anchoring/converting strategy is proposed to restrain the dissolution and realize the rapid conversion of LiPSes. A prototypical regulator comprises of polar catalysts embedded in the interconnected porous muti-walled carbon network (i.e., CoSnO3 nanocubes/CNTs), which promises fast electron/ion transportation and inhibits volumetric effect. Moreover, CoSnO3 as redox accelerator enables the stretched Se−Se bonds to decrease the LiPSes bidirectional conversion barrier, achieving accelerated reaction kinetics. Consequently, the self-reinforcing optimized cathode exhibits superior initial capacity of 730 mAh/g, greatly enlarged capacity after 200 cycles (increase by ∼ 32 % than that of the cell with CNTs), and superior rate capacity (153 mAh/g at 2C). This work uncovers the roles of electronic/ionic conductivity and adsorption/catalysis in Li–Se batteries, providing a guidance for taming the utilization and kinetics of cathode from material perspectives.