H2O/Ni2+ intercalated lamellar vanadium oxide as cathode materials for aqueous zn-ion hybrid supercapacitors

The low power density of batteries and the low energy density of conventional supercapacitors necessitate the development of new energy storage systems. While aqueous Zn-ion hybrid supercapacitor (ZHS) has received extensive attention as an attractive candidate for energy storage devices, its slow ion diffusion dynamics and unsatisfied cycling stability are remained to be addressed. Herein, lamellar structured NixV2O5·nH2O (NVO) with in-situ H2O/Ni2+ intercalation was synthesized and used as cathode materials to assemble Zn-ion asymmetric supercapacitor with the activated carbon as anode. Benefiting from the enlarged the lamellar spacing induced by ion intercalation, the ion diffusion ability was greatly improved and thus the energy storage performance was improved. A specific capacity of 52 mAh g−1 at the current density of 0.1 A g−1 and a power density of 51.6 W kg−1 at energy density of 27.2 Wh kg−1 were achieved. The supercapacitor displayed excellent cycle performance without obvious decay after 5000 cycles. Present work provided experimental support for commercial application of vanadium-based Zn-ion hybrid supercapacitors.