Mesoporous composite nickel cobalt oxide/graphene oxide synthesized via a template-assistant co-precipitation route as electrode material for supercapacitors

A simple co-precipitation method utilizing SDS (sodium dodecyl sulfate) as template and ammonia as precipitant is successfully employed to synthesize nickel cobalt oxide/graphene oxide (NiCo₂O₄/GO) composite. The as-prepared composite (NCG-10) exhibits a high capacitance of 1211.25 F g⁻¹, 687 F g⁻¹ at the current density of 1 A g⁻¹, 10 A g⁻¹ and good cycling ability which renders NCG-10 as promising electrode material for supercapacitors. An asymmetric supercapacitor (ASC) (full button cell) has been constructed with NCG-10 as positive electrode and lab-made reduced graphene oxide (rGO) as negative electrode. The fabricated NCG-10//rGO with an extended stable operational voltage of 1.6 V can deliver a high specific capacitance of 144.45 F g⁻¹ at a current density of 1 A g⁻¹. The as-prepared NCG-10//rGO demonstrates remarkable energy density (51.36 W h kg⁻¹ at 1 A g⁻¹), high power density (50 kW kg⁻¹ at 20 A g⁻¹). The retention of capacitance is 88.6% at the current density of 8 A g⁻¹ after 2000 cycles. The enhanced capacitive performance can be attributed to the improved specific surface area and 3D open area of NCG-10 generated by the pores and channels with the substantial function of SDS.