Energy- and cost-efficient CaCO3-assisted nanoarchitectonics of recycled wheat flour-derived carbon matrix decorated with MnO2 nanoparticles for high-performance supercapacitor

Production cost, electrochemical performance and service life are the key factors in the design and manufacture of electrode materials for supercapacitors. The problems of low capacitance and structure instability can be solved by constructing composites of metal oxide and carbon matrix. Herein, low-cost and high-stability [email protected]2 composite materials, where the three-dimensional (3D) porous wheat flour-derived carbon (WFC) matrix originated from expired wheat flour, which decorated with MnO2 nanoparticles ([email protected]2), was synthesized via an energy- and cost-efficient CaCO3-assisted synthesis route. The prepared electrodes manifest 197 F g−1 at 1.0 A g−1 and outstanding capacitance retention of 100 % after 5000 cycles, substantiating the synergistic effect of the high capacitance of MnO2 and excellent capacity retention of WFC. Furthermore, the symmetric supercapacitor assembled with [email protected]2 as positive and negative electrodes deliver an excellent electrochemical performance and achieve energy density and power density maxima of 17.1 Wh kg−1 and 11,000 W kg−1, and a capacitance retention of 95 % after 5000 cycles. This strategy provides an effective biological fermentation strategy for achieving high-performance and low-cost 3D porous [email protected]2 composites, improving the utilization of waste biomass and promoting environmental protection.