A bimodal porous carbon with high surface area supported selenium cathode for advanced Li–Se batteries

Abstract

A novel bimodal porous carbon (BPC) with high surface area was prepared by a simple hydrothermal route and KOH activation process, and the Se–BPC composite was synthesized for lithium–selenium batteries by the melt-diffusion method. It is found that the elemental selenium was dispersed inside the pores of BPC based on the analyses. Electrochemical tests reveal that the Se–BPC composite has a large reversible capacity and high rate performance as cathode materials. The Se–BPC (45.1wt.% Se) composite displays an initial discharge capacity of 552mAhg−1 and a reversible discharge capacity of 264mAhg−1 after 80cycles at 1C charge/discharge rate. In particular, the Se–BPC composite presents a durable cycling performance at high rate of 2C. These outstanding electrochemical features of Se–BPC composite cathode should be attributed to the uniform BPC with high surface area and bimodal porous structure. The bimodal porous carbon would be a promising carbon matrix to develop high performance lithium–selenium batteries.