Porous carbon derived from corncob as cathode host for Li–Se battery

Corncob was employed as low-cost carbon source to prepare spongy porous carbon by KOH activation and carbonization. The corncob-derived porous carbon (CPC) had multi-level pore structure, with microporous and mesoporous surface and microporous interior. So, CPC had a large specific surface area of 1155 m 2 ·g −1 and micropore volume of 0.431 cm 3 ·g −1 . Se/CPC was fabricated through ball milling and melt diffusion of selenium and CPC mixture powder. Used as cathode active material of Li–Se battery, Se/CPC had a Se loading of 59.83% and maintained a 3D porous structure, providing electrochemical reaction area and volume expansion space. In Li–Se batteries in carbonate electrolyte, the Se/CPC cathode showed a reversible capacity of 608.3 mAh·g −1 , close to theoretical value (675 mAh·g −1 ) at 0.1 C (1 C = 675 mA·g −1 ). After 100 cycles at 0.2 C, 213.2 mA h g −1 remained, while the coulomb efficiency maintained at about 100%. Rate capacity of the Se/CPC at different current densities kept 89.99% of its initial capacity (0.1 C). Thus, the application of corncob to Li–Se batteries provides cheap and environmentally friendly creativities for the preparation of space-confined selenium cathode.