High-energy sodium-ion hybrid capacitors through nanograin-boundary-induced pseudocapacitance of Co3O4 nanorods

A high energy density (175 Wh/kg) sodium-ion hybrid capacitor based on nanograin-boundary-rich hierarchical Co3O4 nanorod anode is reported. Outstanding electrochemical performance is credited to the enhanced pseudocapacitive sodium-ion storage resulting from nanograin-boundaries.