Microwave assisted growth of MnO2 on biomass carbon for advanced supercapacitor electrode materials

Electrode materials play a crucial role in supercapacitors. Developing new electrode materials with rational composition and structure is of big significance. In this work, as typical domestic garbage, peel of passion fruit is used to prepare porous carbon, which is used as support to load MnO2 via a microwave assisted growth strategy afterward. The microwave assisted growth ensures superior structural and electrochemical performances. MnO2 nanoparticles with an approximately size of 30 nm distribute well on carbon matrix. The as-obtained materials are used to fabricate the symmetrical supercapacitors, yielding specific capacitances of 616.3 and 481.4 F g(-1) at 1 and 10 A g(-1), respectively. Additionally, 95.3% of capacitance retention is achieved after 20,000 cycles at 10 A g(-1). These results overmatch many similar devices and more remarkably, waste reuse and synthesis of electrode materials are both achieved in this research. The charge storage mechanism is investigated and reasons for such superior electrochemical performances are explained.