Synthesis of porous biocarbon supported Ni3S4/CeO2 nanocomposite as high-efficient electrode materials for asymmetric supercapacitors

Biocarbon-supported polymetallic composites (CAS@Ni 3 S 4 /CeO 2 ) were fabricated by a facile hydrothermal process. The as-prepared CAS@Ni 3 S 4 /CeO 2 materials integrated the advantages of transition metal sulfides (good conductivity), rare-earth metal oxides (excellent stability), as well as porous carbon with high surface area, thus exhibiting promising electrochemical performance in supercapacitor applications. Indeed, the optimal CAS@Ni 3 S 4 /CeO 2 -150 composite displayed a high specific capacitance of 1364 F g −1 and impressive cycle performance with capacitance retention of 93.81 % after 10,000 cycles. The calculation of capacitance contribution showed that the satisfying behavior of the electrode was a combination of the diffusion process and the surface capacitance characteristics. Furthermore, the assembled asymmetric supercapacitor (CAS@Ni 3 S 4 /CeO 2 -150//CAS) delivered an ultrahigh energy density of 102.76 Wh kg −1 , which was better than that of the commercial activated carbon-based ASC device. This novel strategy might provide a new perspective for transition metal sulfide/rare earth metal oxide composite in the electrochemical energy storage field.