自蔓延高温合成V3TiNi0.56Al0.2贮氢材料及其电化学性能

钒基固溶体贮氢合金因其贮氢量大而成为近年来研究的热点,但传统的纯金属熔炼成本高,限制了其应用。文中从理论上计算了V2O5-TiO2-Ni-Al体系的绝热温度Tad=2879 K和单位质量反应热q=-2.80 kJ/g,表明能够进行自蔓延高温反应,且自蔓延高温合成法制备出了钒基固溶体型贮氢合金V3TiNi0.56Al0.2,通过实验研究了V3TiNi0.56Al0.2贮氢合金的组织结构和电化学性能。结果表明,组织结构与真空感应熔炼制备的基本相同,V3TiNi0.56Al0.2合金最大放电容量为350 mA.h/g,活化性能较好,但循环性能和高倍率放电能力差。

Synthesis of hydrogen storage materials V3TiNi0.56Al0.2 by self-propagating high-temperature and electrochemical properties

As a new kind of storage hydrogen material,vanadium-based solid solution alloy with high hydrogen storage capacity has attracted a lot of attention.However,traditional manufacture of pure vanadium with high cost limits its application.The adiabatic combustion temperature Tad=2 879 K and reaction heat per unit mass q=-2.80 kJ/g on the composition of V2O5-TiO2-Ni-Al systems were calculated firstly.The values of them demonstrate that the self-propagating high-temperature synthesis reaction may occur.New storage hydrogen alloy V3TiNi0.56Al0.2 was prepared by self-propagating high-temperature synthesis(SHS).The microstructure and electrochemical properties of the alloy were investigated from the viewpoint of experiments.The result shows that the microstructure of V3TiNi0.56Al0.2 with SHS is almost the same as that of traditional method;the max discharge capacity of V3TiNi0.56Al0.2 is 350 mA·h/g;V3TiNi0.56Al0.2 prepared by SHS has excellent activation performance,but the cycle lives and high-rate discharge capacity are not good.