CoFe2O4- mesoporous carbons derived from Eucommia ulmoides wood for supercapacitors: Comparison of two activation method and composite carbons material synthesis method

Abstract

The mesoporous activated carbon (AC) was synthesized by low temperature phosphoric acid activation based on Eucommia ulmoides Oliver (EUO) wood (one-step) and EUO-charcoal (two-step). The pore structure, surface composition and graphitization degree of carbons synthesized by one-step and two-step activation were systematically investigated. The results exhibited that the specific surface area of porous carbon varies from 1264.8 m2/g (two-step activation, AC2) to 1506.7 m2/g (one-step activation, AC1), which indicated AC1 gained more well-developed mesoporous structure (the mesoporous ratio reached 75.27 %) than that of AC2. Besides, as CoFe2O4 spinel-type metal oxides nanoparticles (NPs) were anchored on ACs by hydrothermal method and chemical co-precipitation, the electrochemistry characteristics were presented in a three-electrode system. As compared with the products (ACs/CF2) prepared by chemical co-precipitation to prepared, AC1 combined with CoFe2O4 by hydrothermal method (AC1/CF1) showed higher specific capacitance of 596.26 F/g (0.005 V/s), which was profited from the synergistic effect of double-layer capacitance and pseudo-capacitance, and the capacitance retention maintained 93.7 % after 10,000 cycles of charging-discharging at 2 A/g. Therefore, EUO wood is a promising feedstock for the preparation of porous carbon, its metal compound (ACs/CFs) provided excellent performance in potential supercapacitors applications, and by the means of the comparisons for the activation method and the scheme for combination of CoFe2O4, this study generated significative guidance for the preparation of activated carbon and its composite.