High-performance binder-free Co–Mn composite oxide supercapacitor electrode

A thin film binder-free Co–Mn composite oxide (MnCo2O4) electrode was fabricated by using electroless–electrolytic (EE) techniques that is amenable to continuous processing and used for supercapacitor applications. The composite oxide was characterized by XRD, XPS and LIBS. A specific capacitance around 832 F g−1 at a scan rate of 20 mV s−1 was obtained using cyclic voltammetry (CV) and a nearly rectangular-shaped CV curve observed for the composite oxide. When tested in a symmetrical cell setup, the EE electrode yielded a specific capacitance of 240 F g−1 at 74 A g−1 with an energy density of 21 Wh kg−1 and 51.6 kW kg−1 of power density. This work suggests the binder-free Co–Mn composite electrode by the low temperature EE method is a promising candidate for high performing supercapacitors.

► Electroless–electrolytic (EE) synthesis of composite oxide electrocatalysts demonstrated.
► Feasibility of electroless co-deposition of Mn and Co demonstrated.
► Electrochemically stable composite Co–Mn oxide for use in ultracapacitor applications prepared.
► EE prepared Co–Mn oxide yielded both high energy density and high power density in a symmetrical cell set-up.