The Polymer Society of Korea

Abstract

Zinc–iodine batteries offer a high theoretical iodine capacity (211 mAh g⁻¹) and a higher energy density than conventional cathodes. However, polyiodide dissolution causes active material loss and capacity decay. This issue limited ion and electron transport in porous carbon hosts. Here, we propose a pore-engineered hierarchical carbon host to improve iodine stability and charge transfer. As the synthesis temperature increased, mesopore development enhanced surface area and diffusion pathways. This acceleration in redox kinetics led to a host with a high specific surface area of 2657 m² g⁻¹ and a mesopore volume of 0.5491 cm³ g⁻¹. These features maximize the number of active sites and facilitate ion diffusion, achieving 163.4 mAh g⁻¹ after 3400 cycles at 30 C. These results confirm that rational pore structure control suppresses polyiodide dissolution. This offers a practical design strategy for high-performance zinc-iodine batteries.