Electrodeposition chemistry for high-performance I2 cathode

The weak composite driving force of current physical composite technologies cannot maximize the accommodation ability of introduced conductive substrate I2 element and leads to ineffective loading. Insufficient interaction and sluggish charge transfer are not conducive to efficient conversion chemistry and the cycle durability of I2 composite electrodes. Herein, a one-step electrodeposition method is developed to realize the binder-free I2 electrodes using small I− as the precursor. Its exceptional conversion chemistry with high reversibility is verified in a typical aqueous Zn system. Specifically, the obtained carbon cloth-I2 cathode exhibits favorable conversion completion and delivers a high 195 mAh g−1 capacity at 0.5 A g−1. Upon an ultrahigh current density of 4.5 A g−1, satisfactory capacity retention of up to 60% can be achieved. More importantly, with 19% capacity decay, the battery can stably cycle for 2000 cycles with a coulombic efficiency of nearly 100%. The anti-self-discharging function gets significantly enhanced and is accompanied by a low voltage decay rate of 13 mV h−1, benefiting from strong interaction. This universal electrodeposition is excepted to lead the I2 electrodes nearer to commercial requirements.