Porous Co3O4 nanorods as superior electrode material for supercapacitors and rechargeable Li-ion batteries

Abstract

Porous aggregated nanorods of Co3O4 with a surface area of ~100 m2 g−1 synthesized without using any templates or surfactants give very high specific capacitance of ~780 F g−1 when used as electrode in a faradaic supercapacitor, with a cycle life of more than 1,000 cycles. Further, in Li-ion batteries when used as an anode, the Co3O4 nanorods achieved a capacity of 1155 mA h g−1 in the first cycle and upon further cycling it is stabilized at 820 mA h g−1 for more than 25 cycles. Detailed characterization indicated the stability of the material and the improved performance is attributed to the shorter Li-insertion/desertion pathways offered by the highly porous nanostructures. The environmentally benign and easily scalable method of synthesis of the porous Co3O4 nanorods coupled with the superior electrode characteristics in supercapacitors and Li-ion batteries provide efficient energy storage capabilities with promising applications.