Reduced graphene oxide/cobalt sulphides nanoparticle derived from metal-organic framework for supercapacitor application

Electrode materials derived from Metal-organic frameworks (MOF) are becoming interesting materials for supercapacitor application due to their high porous frameworks for facilitating mass and charge transfer. However, the low electrical conductivity and short cycling stability limited their practical application. Herein, reduced graphene oxide/cobalt sulphide nanoparticles derived from MOF with better electrical and ionic conductivity is reported for supercapacitor application. In this work first reduced graphene oxide (rGO) sheet is prepared using sulphur as a template material. Then, the rGO sheet is decorated with abundant cobalt sulphide nanoparticles derived from MOF particles. In this hybrid material the rGO nanosheets served as a physical support backbone with good electrical and ionic conductive layer. On the other hand, the abundant cobalt sulphide nanoparticles decorated on rGO sheets enhanced pseudocapacitive performance of the material. Using this synergistic property, high specific capacitance of 1827 F g(-1) at 3 A g(-1), high retention capability of 81% at a current density of 15 A g(-1) and cycling stability of 82% after 5000 cycles of charge-discharge are obtained. This work shows that hybridizing rGO with MOF-derived materials are promising approach in designing advanced energy storage devices.