Ni 3+ doped cobalt – nickel layered double hydroxides as high-performance electrode materials for supercapacitors †

Co – Ni layered double hydroxides (LDHs), as promising supercapacitor electrode materials with high speci fi c capacity, have su ff ered from poor rate properties and cycling stability. Doping and topochemical oxidation of Ni ions is considered as an e ffi cient route to overcome these drawbacks. In this work, Ni 3+ doped cobalt – nickel layered double hydroxides (Co – Ni-LDHs) were synthesized by pulse laser ablation of a Ni target in CoCl 2 aqueous solution. The existence of Ni 3+ ions doped in Co – Ni-LDHs decreases the conductive resistance, and increases the mobility of surface charge and transfer rate of the electrolyte. As a result, the Ni 3+ doped Co – Ni-LDHs display a maximum speci fi c capacitance of 2275 F g (cid:1) 1 and 1450 F g (cid:1) 1 at the current density of 1 A g (cid:1) 1 and 20 A g (cid:1) 1 , respectively, indicating a high rate of speci fi c capacitance. Moreover, the capacitance retention is 80% after 1800 cycles at the current density of 6 A g (cid:1) 1 , manifesting good cycling stability of Ni 3+ doped Co – Ni-LDHs.