General access to metal oxide (Metal = Mn, Co, Ni) double-layer nanospheres for application in lithium ion batteries and supercapacitors

•A series of metal oxide double layer nanospheres were prepared.•The obtained materials show excellent performances in lithium ion batteries and supercapacitors.•The unique structure of double layers is beneficial for superior electrochemical performances.

In this work, a series of metal oxide double-layer nanospheres (DLNs), such as Mn2O3, Co3O4, NiO, NiCo2O4, and MnCo2O4 have been successfully synthesized through a general template method. The layers of nanospheres were assembled by different nanostructure units and the removing of the SiO2 template formed a void of several ten nanometers between the double layers, resulting large specific surface areas for them. The energy storage performances of the as-prepared double-layer nanospheres were further investigated in lithium ion battery and supercapacitor systems. Based on their unique nanostructures, the double-layer nanospheres exhibit excellent electrochemical performance with long cycle stability and high specific capacities or capacitances. The best of these, DLNs-NiCo2O4 can deliver a reversible capacity of 1107 mAh g−1 at 0.25C after 200 cycles in lithium ion battery system, and shows a capacitance of 1088 F g−1 with capacitance loss of less than 3% at 5 A g−1 after 5000 cycles in supercapacitors.