Nitrogen, phosphorus co-doped carbon cloth as self-standing electrode for lithium-iodine batteries

Rechargeable lithium-iodine (Li-I2) battery is a promising energy storage system because of the high energy and power density. However, the shuttle effects of iodine species and the unstable features of l2 block the practical applications of Li-I2 batteries. Herein, a dual heteroatom doped porous carbon cloth is fabricated as the host material for lithium iodide (Lil). Specifically, the self-standing nitrogen, phosphorus co-doped carb on cloth with high Lil loading exhibits a large specific capacity (221 mAh·g^-1 at 1 C), excelle nt rate capability (95.8% capacity rete ntion at 5 C) and superior I ong cycli ng stability (2,000 cycles with a capacity rete ntion of 96%). Electrochemical kin etic an alysis con firms the domi nant contribution of capacitive effects at high sean rates, which is responsible for the good high-rate performance. The improved electrochemical performance mainly stems from two unique features of nitrogen, phosphorus co-doped porous carbon cloth. Heteroatom doping provides extra active sites for strong adsorption of iodine species while the highly porous structure with large surface area favors the capacitive effects at high rates. This work provides a facile yet efficient approach to regulating both redox reaction and capacitive effects via adjusting surface composition and pore structure of carbon materials for en hanced battery performance.