Affiliation:
1. School of Materials Science and Engineering Jiangsu University of Science and Technology Zhenjiang 212003 P. R. China
2. School of Materials Science and Engineering Sun Yat‐Sen University Guangzhou 510275 P. R. China
Abstract
AbstractDue to the unique “Grotthus mechanism”, aqueous proton batteries (APBs) are promising energy devices with intrinsic safety and sustainability. Although polymers with tunable molecular structures are ideal electrode materials, their unsatisfactory proton‐storage redox behaviors hinder the practical application in APB devices. Herein, a novel planar phenazine (PPHZ) polymer with a robust and extended imine‐rich skeleton is synthesized and used for APB application for the first time. The long‐range planar configuration achieves ordered molecular stacking and reduced conformational disorder, while the high conjugation with strong π‐electron delocalization optimizes energy bandgap and electronic properties, enabling the polymer with low proton diffusion barriers, high redox activity, and superior electron affinity. As such, the PPHZ polymer as an electrode material exhibits fast, stable, and unrivaled proton‐storage redox behaviors with a large capacity of 273.3 mAh g−1 at 0.5 A g−1 (1 C) in 1 M H2SO4 electrolyte, which is the highest value among proton‐inserted electrodes in aqueous acidic electrolytes. Dynamic in situ techniques confirm the high redox reversibility upon proton uptake/removal, and the corresponding protonation pathways are elucidated by theoretical calculations. Moreover, a pouch‐type APB cell using PPHZ electrode exhibits an ultralong lifespan over 30 000 cycles, further verifying its promising application prospect.
Funder
National Natural Science Foundation of China
China Postdoctoral Science Foundation
Basic and Applied Basic Research Foundation of Guangdong Province
Marine Equipment and Technology Institute, Jiangsu University of Science and Technology