Nitrogen-doped litchi-shell derived porous carbon as an efficient iodine host for zinc-iodine batteries

Zinc-iodine batteries (ZIBs) have attracted widespread attention because of their efficient capacity for ion transport and safety. However, the shuttle effect and physical properties of iodine species tremendously hinder their practical applications. Herein, we report a nitrogen-doped biomass litchi-shell derived porous carbon (marked as N-LPC) as the iodine host for ZIBs. The porous-rich structure of N-LPC is favorable for iodine loading and electron/ion transfers. Furthermore, the doping of heteroatomic nitrogen provides abundant anchoring sites to achieve strong interaction with iodine, thus the self-discharge can be suppressed effectively. Accordingly, the N-LPC/I2 composite cathode exhibits a specific capacity of 127 mAh/g at 100 mA g−1, as well as excellent rate capability and cycle stability. This study provides a strategy for discovering the cost-effective carbonaceous iodine host material.