Facile synthesis of birnessite-type manganese oxide nanoparticles as supercapacitor electrode materials

Birnessite was facilely prepared by adding dropwise NH2OH·HCl to KMnO4 solution under ambient temperature and pressure. The as-prepared nanostructured birnessite shows high specific capacitance and excellent cyclic stability, and the capacitive performance is mainly affected by specific surface area and pore volume.206