Rational design of unique graphene modified cobalt manganite hollow microcubes for supercapacitors

Highlights: • First reported rGO modified CoMn₂O₄ hollow microcubes hybrid system. • The CoMn₂O₄@rGO electrode had a higher specific capacitance of 1194.7 F g⁻¹. • The electrode kept 88.6% capacitance retention after 5000 cycle. • The satisfactory performance was attributed to the material nature and special structure. A novel reduced graphene oxide (rGO) modified ternary metal oxide electrode material with rational microstructure was successfully developed by the hydrothermal approach following the heat treatment, in which gauze-like rGO sheets were homogeneously decorated on the surfaces of uniform CoMn₂O₄ hollow microcubes. Benefitting from this special hybrid morphology possessing large specific surface area and good conductivity, the CoMn₂O₄@rGO composite gave rise to a greater specific capacitance of 1194.7 F g⁻¹ at a low current density of 2 mA cm⁻², longer cycle life (88.6% capacitance retention after 5000 cycles), and more excellent rate performance when fabricated into a promising electrode for electrochemical supercapacitors.