Selenium/pomelo peel-derived carbon nanocomposite as advanced cathode for lithium-selenium batteries

Fruit waste pomelo peel was employed as raw material to prepare a highly porous and partial graphitized carbon material (pomelo peel-derived carbon (PPDC)). Se/PPDC nanocomposite was fabricated through ball milling and melt diffusion of selenium and PPDC mixture powder. The characterization results showed that selenium with 47 % loading content were confined homogenously in the small pores (< 4 nm) of the PPDC matrix. As a novel cathode material for rechargeable lithium batteries, Se/PPDC exhibited high specific capacity, good cycling stability, and C-rate performance when using sodium alginate (SA) as binder and low-cost LiPF6-EC-DEC as electrolyte. During the initial 30 cycles, a steady capacity of 650 mAh g(-1) approaching to theoretic specific capacity was obtained at a current density of 150 mA g(-1). At a high current density of 900 mA g(-1), Se/PPDC delivered a reversible capacity of 410 mAh g(-1) with nearly 100 % coulombic efficiency. The advanced electrochemical performance of Se/PPDC demonstrated that PPDC would be a promising porous carbon substrate to develop space-confined selenium cathode for rechargeable lithium batteries.