Physico-Chemical Doubly Confinement and Chloride Ion Activation Enabled Two-Electron Conversion Zn-I2 Battery

Aqueous zinc-iodine (Zn-I2) batteries are emerging as promising alternatives to lithium-ion batteries, boasting high theoretical capacity along with abundant natural resources and environmental safety. The redox chemistry of iodine in these batteries, exploiting its multiple valence states, offers potential for intricate multi-electron conversion reactions. However, challenges such as iodine's volatility and poor conductivity hinder direct use as a cathode material, impacting battery efficiency and cycle life. Strategies involving physico-chemical adsorption in carbon-based hosts show promise by enhancing iodine loading and stability. A synthesized porous carbon material, enriched with carbonate functional groups, achieved a remarkable iodine loading efficiency of 66.69 wt.%. When applied as the cathode in a Zn-I2&Cl battery configuration, incorporating two-electron conversion of iodine via chloride ions activation, it demonstrated a specific capacity exceeding 200mAh g-1 at 1C, with stable cycling performance over 600 cycles at 5C. This approach underscores the critical role of tailored cathode materials in advancing Zn-I2 battery technology.