Solvothermal synthesis of Y-doped alpha-nickel hydroxide flower-like nanostructure for aqueous asymmetric supercapacitors

摘要

Y-doped alpha-nickel hydroxide flower-like nanostructure was successfully prepared via one-step solvothermal process. The BET surface areas of the Ni(OH)(2) flower-like are improved by doping of Y. When the Y3+ /Ni2+ mole ratio is 5%, the doped Ni hydroxide obtains a maximum specific capacity (735.36 C g(-1) at a current density of 1 A g(-1)), which is higher than pure sample (489.4 C g(-1)). The enhanced electrochemical performances may be attributed to fact that the doped samples expose more active sites for fast redox reactions, and the incorporation of Y accelerates the reaction kinetics and charge transfer efficiency and reaction kinetics. Aqueous asymmetric supercapacitor using YNi5 as the positive electrode and AC material as negative electrode shows an energy density of 68.3 Wh kg(-1) at a power density 1093.7 W kg(-1), and good cycling performance (82.37% retention after 8000 cycles).