Confining iodine into a biomass-derived hierarchically porous carbon as cathode material for high performance zinc–iodine battery

The practical application of aqueous zinc-iodine (Zn-I2) battery is mainly hindered by the limited electrical conductivity, sluggish kinetics and severe shuttle effect. In this regard, herein, we designed a biomass-derived hierarchically porous carbon (marked as BCHP) as an iodine host material for high-performance Zn-I2 battery. The hierarchically porous structure of BCHP is favourable for iodine confinements, electrolyte permeation as well as electron/ion transfers. As a result, the I-BCHP electrode exhibits superior electrochemical performance. A high discharge capacity of 100 mAh g−1 is still retained for over 150 cycles at a current density of 100 mA g−1. Our study provides an economical and effective scheme for the significant improvement of Zn-I2 battery performance.