Zinc-ion storage mechanisms in poly(o-phenylenediamine): insights into structural advantages and electrochemical performance

Zinc-ion organic batteries (ZOBs) are emerging as a viable energy storage alternative, valued for their superior safety features and economic viability. Poly(o-phenylenediamine) (PoPDA), recognized for its cost efficiency, has emerged as a potential cathode candidate in ZOB systems. However, the rapid decline in specific capacity and the limited cycle life of PoPDA-based electrodes have hindered the advancement and utilization of these electrodes. In this research, high molecular weight poly(o-phenylenediamine) (PoPDA_H) was synthesized through in situ chemical oxidative polymerization to serve as an efficient cathode material for zinc-ion organic batteries (ZOBs). This composite exhibited a high capacity of 258 mAh g⁻¹ at 0.1 A g⁻¹ and retained 97.4% of its capacity after 2000 cycles at 1.0 A g⁻¹, emphasising the significant potential of PoPDA_H in the pursuit of high-performance ZOB electrode materials.