Structure evolution of oxygen removal from porous carbon for optimizing supercapacitor performance  

作　　者：Siting Yuan Xianhong Huang Hao Wang Lijing Xie Jiayao Cheng Qingqiang Kong Guohua Sun Cheng-Meng Chen 

机构地区：[1]CAS Key Laboratory of Carbon Materials,Institute of Coal Chemistry,Chinese Academy of Sciences,Taiyuan 030001,Shanxi,China [2]Center of Materials Science and Optoelectronics Engineering,University of Chinese Academy of Sciences,Beijing 100049,China [3]University of Chinese Academy of Sciences,Beijing 100049,China

出　　处：《Journal of Energy Chemistry》2020年第12期396-404,共9页能源化学（英文版）

基　　金：National Science Foundation for Excellent Young Scholars of China (21922815);Key Research and Development (R&D) Projects of Shanxi Province (201903D121007);Natural Science Foundations of Shanxi Province (201801D221156);DNL Cooperation Fund of CAS (DNL180308);Science and Technology Service Network Initiative of CAS (KFJ-STS-ZDTP-068);Youth Innovation Promotion Association of CAS。

摘　　要：The presence of oxygen functional groups is detrimental to the capacitive performance of porous carbon electrode in organic electrolyte. In this regards, hydrogen thermal reduction has been demonstrated effective approach in removing the unstable surface oxygen while maintaining the high porosity of carbon matrix. However, the exact evolution mechanism of various oxygen species during this process, as well as the correlation with electrochemical properties, is still under development. Herein, biomass-based porous carbon is adopted as the model material to trace its structure evolution of oxygen removal under hydrogen thermal reduction process with the temperature range of 400–800 °C. The optimum microstructure with low oxygen content of 0.90% and proper pore size distribution was achieved at 700°C. XPS, TPRMS and Boehm titration results indicate that the oxygen elimination undergoes three distinctive stages(intermolecular dehydration, hydrogenation and decomposition reactions). The optimum microstructure with low oxygen content of 0.90% and proper pore size distribution was achieved at 700 °C. Benefiting from the stable electrochemical interface and the optimized porous structure, the as-obtained HAC-700 exhibit significantly suppressed self-discharge and leak current, with improved cycling stability, which is attributable to the stabilization of electrochemical interface between carbon surface and electrolyte. The result provides insights for rational design of surface chemistry for high-performance carbon electrode towards advanced energy storage.

关 键 词：Starch-based activated carbon Oxygen functional groups Hydrogen thermal reduction Structural evolution Organic electrolytes ELECTROCHEMISTRY 

分 类 号：TQ127.11[化学工程—无机化工] TM53[电气工程—电器]