NH4V4O10 nanobelts as a novel cathode material for aqueous nickel ion batteries

Rechargeable aqueous nickel-ion batteries have been developed due to the high volumetric capacity, smaller ionic radius and high safety. However, it is limited by the cathode materials, which require a stable host structure due to the strong electrostatic interaction with Ni2+. Herein, a novel ammonium vanadate NH4V4O10 as a cathode for aqueous nickel-ion batteries is reported. A high specific discharge capacity of 144 mAh g  1 can be obtained at a current density of 50 mA g  1, and a good capacity retention of about 66 % is achieved after 200 cycles at 200 mA g  1. The NH4+ in the host structure is irreversibly displaced by Ni2+, which is profit to improve the capacity.