Holey graphene with nano-sized holes has numerous electrochemically active sites and an open porous structure, imparting a higher electrocatalytic activity and faster electron and ion transport compared with basal planes in graphene. In this study, holey graphene-based electrode materials, prepared using holey graphene as building blocks, are applied in both electric double-layer capacitor- and lithium-ion battery-type electrodes, because holey graphene possesses more electrochemically active sites originating from the edge sites and facilitates faster electron/ion transport through the holes. The enhanced specific capacity of holey graphene can be attributed to its edge sites, because an additional electric double-layer is formed at the edges. The enhanced rate capability of the Li4Ti5O12/holey graphene composite can be attributed to the in-plane holes, because they enhance lithium-ion transport across the graphene to Li4Ti5O12. We successfully design a hybrid supercapacitor consisting of holey graphene and the Li4Ti5O12/holey graphene composite. The hybrid supercapacitor delivers a maximum energy density of 117.3 Wh·kg−1 at a power density of 0.1 kW·kg−1, and a maximum power density of 19.7 kW·kg−1 is achieved at an energy density of 43.1 Wh·kg−1. The outstanding energy and power density demonstrate the increased specific capacitance of the capacitor-type electrode and rate capability of the battery-type electrode.
Bibliographical noteFunding Information:
This work was supported by the Korea Institute of Energy Technology Evaluation and Planning and the Ministry of Trade, Industry and Energy of the Republic of Korea (No. 20172420108590). This work was supported by the Technology Innovation Program (10062226, Development of flexible hybrid capacitr (0.25 mWh/cm2) composed of graphene-based flexible electrode and gel polymer electrolyte with high electrolyte uptake) funded by the Ministry of Trade, Industry & Energy, Korea. This work was supported by Korea Institute of Energy Technology Evaluation and Planning (KETEP) grant funded by the Korea goverment (MOTIE) (20172410100150). This work was supported by the Industry Technology Development Program (10080540, Development of filmtype flexible supercapacitor with microstructured electrodes based on nanomaterials) funded by the Ministry of Trade, Industry & Energy (MOTIE, Korea).
All Science Journal Classification (ASJC) codes
- Environmental Chemistry
- Chemical Engineering(all)
- Industrial and Manufacturing Engineering