Rational design of microsphere and microcube MnCO3@MnO2 heterostructures for supercapacitor electrodes

MnCO3 microsphere@MnO2 and MnCO3 microcube@MnO2 heterostructures have been synthesized for supercapacitor electrodes through self-assembly and oxidation process. The morphologies of MnCO3 are effectively controlled by adding (NH4)2SO4 solution. The MnCO3 microsphere@MnO2 and MnCO3 microcube@MnO2 heterostructures display high capacitances of 363 F g−1 and 290 F g−1 at 1 A g−1, respectively. In addition, the assembled asymmetric supercapacitor based on MnCO3 microsphere@MnO2 and active grapheme (AG) exhibits a high energy density of 27.4 Wh kg−1 at a power density of 271.7 W kg−1. The synthetic strategy provides a fine reference for metal oxide structures and the results indicate the MnCO3 microsphere@MnO2 and MnCO3 microcube@MnO2 heterostructures electrodes can be a promising material for energy storage applications.