Highly Proton-Conductive Solid-State Electrolyte Based on Covalent Organic Framework for Proton Battery Application
Bing Tang, S. Y. Liu, Xinrui Ma, Feng‐Jia Zhao, Guo-Qin Zhang, Xu-Sheng Gao, Jiazhi Yang, Hong‐Bin Luo, Xiao‐Ming Ren
Abstract
Solid-state proton batteries are emerging as promising technologies for energy storage. However, efficient solid-state protonic electrolyte development remains in its early stages. Herein, we report the preparation and potential application of a high-performance covalent organic framework (COF)-based protonic electrolyte for solid-state proton batteries. Using a mechanochemical method, H 3 PO 4 was incorporated into the channels of a sulfonated COF (COF-SO 3 H) to produce the composite solid-state electrolyte, H 3 PO 4 @COF-SO 3 H. This composite was thoroughly characterized using techniques such as powder X-ray diffraction, 13 C NMR spectroscopy, X-ray photoelectron spectroscopy, and nitrogen adsorption/desorption analysis. Impedance spectroscopy revealed that H 3 PO 4 @COF-SO 3 H exhibited superprotonic conductivity exceeding 10 –2 S cm –1 under ambient conditions, alongside remarkable long-term stability and a broad electrochemical stability window. A solid-state proton battery assembled using H 3 PO 4 @COF-SO 3 H as the electrolyte demonstrated exceptional performance, including excellent rate capability, high specific capacity of 101.8 mAh g –1 at 1.0 A g –1, and good cycling stability with a capacity retention of 80.6% after 1000 cycles at 1.0 A g –1, outperforming previously reported solid-state proton batteries. These findings suggest that COF-based composite solid-state electrolytes hold significant promise for future applications in solid-state proton batteries.