Significantly improved cycling stability for electrochemical hydrogen storage in Ti1.4V0.6Ni alloy with TiN

Ti1.4V0.6Ni alloy contained icosahedral quasicrystals can be electrochemically charged and discharged with the maximum capacity of approximately 270 mAh g−1, however this alloy shows poor cycling stability, making it difficult to develop the practical application. Here, new TiN-added Ti1.4V0.6Ni composites are prepared by ball-milling. The electrochemical performance of the composites as negative active ingredient of Nickel-metal hydride(Ni-MH) battery is compared with Ti1.4V0.6Ni. Benefiting from the excellent catalysts for HER, electrical conductivity and resistance to oxidation/corrosion of TiN, TiN-added Ti1.4V0.6Ni composites exhibit excellent cycling stability as well as charge retention(89.7% after 24 h relaxation). The cycling capacity retention rate for these electrodes is approximately 80% after a preliminarytest of 50 continuous cycles. But meanwhile, the maxium discharge capacity falls into about 250 mAh g−1, and the electrocatalytic activity improvement is hightly demanded.This work presents a practical method for using TiN as an additive for enhancing the cycling stability of hydrogen storage alloy.