Effect of transition element Cr substituting on hydrogen storage properties of Ti-Ce-V-Mn hydrogen storage alloy

Abstract

The TiMn₂ intermetallic alloy system exhibits promising application prospects in batteries made from nickel metal hydride and hydrogen turbines. Unfortunately, the plateau slope and hysteresis phenomenon of this system restrict its practical applications. The effect of partial substitution of Mn by transition element Cr in Ti_0.95Ce_0.05V_0.45Cr_xMn_1.5-x (x = 0, 0.05, 0.1, 0.15, 0.2) alloy on tissue and hydrogen storage properties was investigated in order to improve these weaknesses. The results show that the C14 Laves phase (space group: P63/mmc) is the primary phase of the alloy, with traces of the CeO₂ phase (space group: Fm-3m) present as well. According to the PCT test and analysis, the alloy has the largest hydrogen storage capacity and the lowest plateau slope rate when the Cr content is 0.1. At the same time, the alloy's performance is optimized during hydrogen adsorption and desorption, as evidenced by the lowest desorption enthalpy change of 21.09 kJ/mol and lowest hysteresis coefficient when the Cr content is 0.2. When compared to the non-Cr doped alloy, the Cr doped alloy exhibits better kinetic characteristics, including higher rates of hydrogen absorption and desorption. Finally, the findings indicate that the alloy performs better than other types of TiMn₂ alloy and has been found to have good application prospects. The study's conclusions offer insightful knowledge for the real-world use of solid-state hydrogen storage.