High capacity hydrogen storage alloy negative electrodes for use in nickel–metal hydride batteries

• Rare earth-free TiV2.1−xCrxNi0.3 (x = 0.4–1.0) alloys were prepared by arc-melting.
• All alloys were composed of two phases, bcc phase and TiNi-based phase.
• The higher Cr content, the lower discharge capacity, the higher cycle durability.
• The lower charge-transfer resistance led to the higher HRD.
• The TiV1.6Cr0.5Ni0.3 alloy electrode had the highest HRD.

Rare earth-free V-based TiV2.1−xCrxNi0.3 (x = 0.4–1.0) alloys were prepared by arc-melting. All alloys were composed of two phases, the primary phase in which the V and Cr constituents were mainly distributed and the secondary phase in which the Ti and Ni constituents were mainly distributed. When the Cr content was increased, the maximum discharge capacity was decreased, but charge–discharge cycle durability was improved. The lower the charge-transfer resistance and the higher the specific discharge current at which the positive shift of potential at degree of discharge of 50% stagnates, the higher the HRD. In the present study, the TiV1.6Cr0.5Ni0.3 alloy electrode had the highest HRD.