Biomass derived porous carbon supported nano-Co3O4 composite for high-performance supercapacitors

Carbon based composites derived from various biomasses have exhibited excellent application prospects in the field of supercapacitors . Herein, the Co 3 O 4 nanoparticles supported on biomass eggfruit-derived porous carbon (EPC) was prepared via solvothermal method and subsequent calcination , in which the shells of eggfruit's kernel (SEK) were used as carbon source and cobalt phthalocyanine was employed as precursor of Co 3 O 4 . The resultant composite was denoted as Co 3 O 4 @EPC and its supercapacitive performances were checked in details. Scanning electron microscopy and transmission electron microscopy images of Co 3 O 4 @EPC show that EPC has a three-dimensional porous network structure, and Co 3 O 4 nanoparticles with an average particle size of 7 nm are uniformly dispersed on the EPC carrier. In the three-electrode system with 6 mol L −1 KOH as electrolyte, the specific capacitance of Co 3 O 4 @EPC/Ni foam electrode is 781 F g −1 at the current density of 0.5 A g −1 , which is much higher than that of p-Co 3 O 4 electrode (429.69 F g −1 at 0.5 A g −1 ) or EPC (125.39 F g −1 at 0.5 A g −1 ) electrode under the same conditions. The energy density of a two-electrode device with Co 3 O 4 @EPC/Ni foam electrode as positive electrode and EPC/Ni foam electrode as negative electrode was 32.8 Wh K g −1 at the power density of 1333 W K g −1 . In addition, the device has good cyclic stability with a capacitance retention rate of 96.7% after 20,000 cycles. These results indicate that the excellent properties of the Co 3 O 4 @EPC make it a potential electrode material for high-performance supercapacitors .