Fabrication of cobalt aluminum-layered double hydroxide nanosheets/carbon spheres composite as novel electrode material for supercapacitors
(1. School of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China;
2. College of Chemistry and Materials Science, Longyan University, Longyan 364012, China)
Abstract: A new design route was presented to fabricate cobalt aluminum-layered double hydroxide(CoAl-LDH) thin layers which grow on carbon spheres(CSs) through a growth method. The CoAl-LDH thin layers consist of nanoflakes with a thickness of 20 nm. The galvanostatic charge-discharge test of the CoAl-LDH/CSs composite shows a great specific capacitance of 1198 F/g at 1 A/g (based on the mass of the CoAl-LDH/CSs composite) in 6 mol/L KOH solution, and the composite displays an impressive specific capacitance of 920 F/g even at a high current density of 10 A/g. Moreover, the composite remains a specific capacitance of 928 F/g after 1000 cycles at 2 A/g, and the specific capacitance retention is 84%, indicating that the composite has high specific capacitance, excellent rate capability and good cycling stability in comparison to pristine CoAl-LDH.
Key words: cobalt aluminum-layered double hydroxide; carbon sphere; supercapacitor; growth method