MnO2@Corncob Carbon Composite Electrode and All-Solid-State Supercapacitor with Improved Electrochemical Performance

Xin-Sheng Li; Man-Man Xu; Yang Yang; Quan-Bo Huang; Xiao-Ying Wang; Jun-Li Ren; Xiao-Hui Wang

doi:10.3390/ma12152379

MnO₂@Corncob Carbon Composite Electrode and All-Solid-State Supercapacitor with Improved Electrochemical Performance

Materials (Basel). 2019 Jul 26;12(15):2379. doi: 10.3390/ma12152379.

Authors

Xin-Sheng Li¹, Man-Man Xu¹, Yang Yang¹, Quan-Bo Huang¹, Xiao-Ying Wang¹, Jun-Li Ren¹, Xiao-Hui Wang²

Affiliations

¹ State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou 510640, China.
² State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou 510640, China. fewangxh@scut.edu.cn.

Abstract

Two corncob-derived carbon electrode materials mainly composed of micropores (activated carbon, AC) and mesopores/macropores (corncob carbon, CC) were prepared and studied after the anodic electrodeposition of MnO₂. The capacity of the MnO₂/activated carbon composite (MnO₂@AC) electrode did not noticeably increase after MnO₂ electrodeposition, while that of the MnO₂/corncob carbon composite (MnO₂@CC) electrode increased up to 9 times reaching 4475 mF cm^-2. An asymmetric all-solid-state supercapacitor (ASC) was fabricated using AC as the anode, MnO₂@CC as the cathode, and polyvinyl alcohol (PVA)/LiCl gel as the electrolyte. An ultrahigh specific capacitance of 3455.6 mF cm^-2 at 1 mA cm^-2, a maximum energy density of 1.56 mW h cm^-2, and a long lifetime of 10,000 cycles can be achieved. This work provides insights in understanding the function of MnO₂ in biomass-derived electrode materials, and a green path to prepare an ASC from waste biomass with excellent electrochemical performance.

Keywords: MnO2; architecture; natural biomass; porous carbon; supercapacitor.