International Journal of Hydrogen Energy, Vol.45, No.3, 2157-2167, 2020
A layered porous Ni structure contributes to superior low-temperature performance of hydrogen storage alloys
The poor low-temperature performance of negative electrode materials- hydrogen storage alloys (HSAs) has impeded applications of nickel metal hydride batteries in new energy vehicles. Here, we propose a simple and effective strategy to improve low-temperature properties of the commercial HSA with HCl etching and heat treatment. The layered porous Ni surface structure formed during this process improves the electrochemical reaction kinetics, and thus results in a larger discharge capacity of 102.63 mAh g(-1) at 233 K compared with those of bare (11.52 mAh g(-1)) and acid-corroded (43.00 mAh g(-1)) alloys. This method could be extended to enhance the low-temperature performance of other HSA systems. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.