NiO has been intensively studied as a promising electrode material for supercapacitors because of its high theoretical specific capacitance, well-defined redox behavior, and good chemical compatibility with nickel foam. However, it still suffers from inferior rate capability and cycling stability because of the simple component and random structural integration. Herein, we report a tunable sulfuration process of NiO nanosheets constructed on porous nickel foam for supercapacitor applications. The resulting NiO/Ni3S2 with distinct structural features exhibits an ultra-high specific capacitance of 2153 F g-1 at a current density of 1 A g-1, and the capacitance is retained at 1169 F g-1 even at a current density as high as 30 A g-1. An asymmetric supercapacitor device fabricated with NiO/Ni3S2 as the positive electrode and activated carbon as the negative electrode delivers high energy and power densities (52.9 W h kg-1 at 1.6 kW kg-1; 26.3 W h kg-1 at 6.4 kW kg-1), and good cycling stability (a capacitance retention of 92.9% over 5000 cycles).
Bibliographical noteFunding Information:
This work was fully supported by the Korean Government (MSIP) (No. 2015R1A5A1037668) through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (MEST).
© The Royal Society of Chemistry.
All Science Journal Classification (ASJC) codes
- Renewable Energy, Sustainability and the Environment
- Materials Science(all)