Self-Assembled Mof Derived CoC/Rgo as Positive Electrode Material for a Supercapattery with High Energy Density

Co@C core-shell particles with a uniform size of approximately 100 nm anchored on rGO nano sheets is synthesized by a one-pot hydrothermal process. The Co@C particle formation is realized with a self-assembly procedure of metal-organic framework (MOF), and with GO as the precursor of rGO, Co@C/rGO is achieved. After calcination, the synthesized Co@C/rGO with high crystallization is obtained. Fabricated as an electrode by electrophoretic deposition, the calcined Co@C/rGO is evaluated with a high specific capacity of 810 Cg-1 at a current density of 1 Ag-1. With the calcined Co@C/rGO served as positive electrode and with as-prepared 3D rGO aerogel as negative electrode, an assembled asymmetric supercapattery possesses a wide operating potential window of 1.2 V. The specific capacitance of the supercapattery can be as high as 120 Fg-1 at 0.6 Ag-1, while the energy density reaches 29.5 Whkg-1 at a power density of 720 Wkg-1, and 11.2 Whkg-1 at 12,000 Wkg-1. After 10,000 cycles of charge-discharge process at 5 Ag-1, the asymmetric supercapattery device shows considerable cyclic stability with capacitance retention of 93.7%