Three-dimensional porous composite Mn2O3@PPy as cathode material for zinc ion battery with high energy density

Mn-based materials are among the most promising Zn-ion batteries (ZIBs) cathode materials. However, their inherently poor conductivity and structure collapse hinder their practical application. Herein, Mn2O3@polypyrrole (PPy) porous spheres are prepared using a hydrothermal method. Coating Mn2O3 with PPy, a conductive polymer, improves its conductivity and inhibits Mn dissolution during electrochemical reactions. The Mn2O3@PPy cathode exhibits remarkable electrochemical performance and an excellent specific capacity of 287.7 mAh·g−1 after 300 cycles at 0.1 A g−1. The cathode maintains a specific capacity of 73.5 mAh·g−1 after 3000 cycles at 3.0 A g−1 and exhibits an excellent cycle life. In addition, the co-insertion/extraction of H+ and Zn2+ and formation/dissolution mechanism of zinc sulfide hydrate of the Mn2O3@PPy electrode are evaluated theoretically using several methods. The energy density of the cathode at the power density of 98.7 W kg−1 is 602.8 Wh·kg−1, which is higher than those of numerous previously reported advanced ZIBs cathodes.