Biomass waste derived multi-hierarchical porous carbon combined with CoFe2O4 as advanced electrode materials for supercapacitors

As a common seafood waste, crab was employed as the biomass carbon source to synthesize porous carbon materials, and used as supercapacitor electrode materials. The multi-hierarchical porous structure can be obtained by a novel three-step method. The crab derived carbon exhibited a specific capacitance of 320.4 Fg(-1) at a current density of 1 Ag-1, and demonstrated the impressive cycling stability over 20000 cycles with 91.3% of retention at 1 Ag-1. Additionally, the crab derived carbon was combined with CoFe2O4 , a typical pseudocapacitive active material, to develop an advanced hybrid supercapacitor. The results indicated that the ratio of CoFe2O4 to crab derived carbon affected capacitive performances of the composites. The optimal sample yielded a high specific capacitance of 701.8 Fg(-1) at 1 Ag-1. Moreover, it displayed the excellent cycling performance over 10000 cycles with 90.9% of capacitance retention. Such green and high-performance hybrid electrodes are in accordance with the principle of "waste to treasure", showing great potential in energy storage applications. (C) 2018 Elsevier B.V. All rights reserved.