Gyeongseop Lee
Seoul National University, South Korea
Title: Size-controllable Co3O4 nanograin-decorated Co(OH)2 sheets synthesized with MOF templates for high-performance all-solid-state asymmetric supercapacitor electrodes
Biography
Biography: Gyeongseop Lee
Abstract
In this study, a novel hybrid structure of homogeneously distributed Co3O4 nanograins on a hexagonal Co(OH)2 plate (CNG/Co(OH)2) is synthesized using a one-pot hydrothermal reaction of zeolitic imidazolate framework-67 (ZIF-67). Particularly, because Co-containing ZIF-67 serves as a self-template during the hydrothermal conversion process, various-sized CNG/Co(OH)2 can be prepared using different sizes of ZIF-67 as the precursor material. The unique structural features of CNG/Co(OH)2 effectively boost the electrochemical activation of the active materials (i.e., Co3O4, Co(OH)2) by preventing aggregation. Among the various-sized CNG/Co(OH)2, large-sized CNG/Co(OH)2 (L_CNG/Co(OH)2) exhibits the highest capacitance (1284 F g−1 at 1 A g−1), indicating that the electrochemical performance is improved as the size of the hybrid architecture increases. Furthermore, multifarious all-solid-state asymmetric supercapacitors (ASCs) are successfully fabricated with various-sized CNG/Co(OH)2 as the positive electrode and mesoporous plasma-reduced graphene oxide (MPRGO) as the negative electrode. Owing to the synergistic contributions from the two electrodes, the L_CNG/Co(OH)2-based ASC delivers a maximum energy density of 41.2 Wh kg−1 at 2.8 kW kg−1, and holds 31.5 Wh kg−1, even at the highest power density of 45 kW kg−1, demonstrating great potential for next-generation energy storage devices.