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

• A novel bimodal porous carbon (BPC) with high surface area was prepared.
• The BPC as matrix to load selenium for lithium–selenium battery cathodes
• The Se–BPC composite shows excellent rate capability and high capacity retention.
• The Se–BPC composite presents a durable cycling performance at high rate of 2 C.

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 (45.1 wt.% Se) composite displays an initial discharge capacity of 552 mAh g− 1 and a reversible discharge capacity of 264 mAh g− 1 after 80 cycles at 1 C charge/discharge rate. In particular, the Se–BPC composite presents a durable cycling performance at high rate of 2 C. 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.