Rational Surface Tailoring Oxygen Functional Groups on Carbon Spheres for Capacitive Mechanistic Study

• DOI: 10.1021/acsami.8b22370
• Publication Date: 2019-03-19T18:42:13Z
• Authors: Dongdong Zhang; Jianlong Wang; Chong He; Yuzi Wang; Taotao Guan; Jianghong Zhao; Jinli Qiao; Kaixi Li
• Keywords: Pseudocapacitance; Carbon fibers; Horizontal scan rate

Porous carbons represent a typical class of electrode materials for electric double-layer capacitors. However, less attention has been focused on the study capacitive mechanism electrochemically active surface oxygen groups rooted in porous carbons. Herein, degree and variety HNO3-modified samples (N-CS) are finely tailored by mild hydrothermal oxidation (0.0-3.0 mol L-1), while micro-meso-macroporous structures efficiently preserved from original sample. Thus, N-CS is suitable carrier separately discussing contribution functional to electrochemical property. The optimized shows high capacitance 279.4 F g-1 at 1 A g-1, exceeding 52.8% pristine carbon sphere (CS) (182.8 g-1) KOH electrolyte. On further deconvoluting redox peaks cyclic voltammetry curves, we find that pseudocapacitance not only associates with surface-controlled faradic reaction scan rate but also dramatically stems diffusion-controlled through potassium hydroxyl ion insertion/deinsertion into underutilized micropores low rate. assembled supercapacitor based presents stable energy density 5 Wh kg-1 over wide range power 250-5000 W kg-1, which higher than 0.0N-CS In TEABF4 electrolyte, an 26.9 1350 exhibits excellent cycling stability retention 93.2% 2 after 10 000 cycles. These results demonstrate alter