高活性抗氧化镁镍基氢化物自演变脱氢机制

镁基金属氢化物因具有较高的储氢容量和价格低廉等优势而被认为是理想的储氢材料之一，目前存在的一个关键问题是其反应活性的增加带来易氧化及苛刻的储运条件。本项目基于我们实验发现的微米级镁镍基氢化物在空气暴露过程中不仅没有发生氧化失活，反而存在脱氢性能得到改善的自演变脱氢行为，瞄准空气稳定型高活性镁基储氢材料，首先通过氢化燃烧合成工艺制备镁镍氢化物，深入研究镁镍氢化物在空气氛环境下的自演变脱氢行为，阐明具有特殊脱氢行为的镁镍氢化物自演变脱氢机制；其次，引入调控因子实现其自演变脱氢性能的人工可控并阐明机制；最后，构筑具有自演变脱氢行为的高容量富镁氢化物体系，并揭示基于自演变脱氢机制和多相协同脱氢机制的共同作用机理。通过本项目的开展，为改性镁基储氢材料提供新型策略，并为加快镁基储氢材料作为氢能源载体的实用化进程提供理论支撑和实践基础，同时也为其它固态氢化物储氢性能的改善提供新的思路。

Magnesium-based metal hydride is regarded as one of the ideal hydrogen storage materials owing to its high hydrogen storage capacity and low cost. However, the high reaction activity of magnesium-based hydride means that it is susceptible to oxidation, requiring strict condition of storage and transportation. Our preliminary experimental results have shown that the reaction activity of micron-scale magnesium-nickel-based hydride does not decrease when exposure to air. Instead, the dehydrogenation performance is improved unexpectedly, exhibiting a novel behavior of self-evolution dehydrogenation. Based on the above results, this project will develop air-stable and high-active magnesium-based hydrogen storage material. Initially, we will synthesize magnesium nickel hydride by hydriding combustion synthesis. The self-evolution dehydrogenation behavior of the as-prepared magnesium nickel hydride in air will be studied systematically, and its self-evolution dehydrogenation mechanism will be clarified. Then, the self-evolution dehydrogenation performance will be modulated artificially by introducing various modulation factors, and the modulation mechanism will be clarified. Finally, the high capacity and magnesium-rich hydride system with self-evolution dehydrogenation behavior will be designed, and the combined action mechanism based on self-evolution dehydrogenation and multiphase synergistic dehydrogenation will be revealed. This study will provide a novel strategy for improving magnesium-based hydrogen storage materials, and lay theoretical and practical foundation for accelerating the application of magnesium-based hydrogen storage material as hydrogen energy carrier, and also give a fresh idea for the enhancement of hydrogen storage performance of other solid state hydrides.