Li-Mg-N-H体系的导热性能与可逆储氢性能之间的关联及其热化学研究

金属氮氢储氢材料Li-Mg-N-H体系以其理论储氢容量高的特点引起了各国科研工作者的极大兴趣，是目前储氢材料研究领域的热点之一。但此类储氢材料存在着固-固相反应传质传热差、放氢反应温度高、吸放氢动力学阻力大、低温时可逆吸氢性能较差等问题，针对存在的以上问题，本项目拟以Li-Mg-N-H体系为研究对象，考察引入各种不同离子半径和电负性的轻金属及其化合物（如KNH2）或其他加热熔融（如NH3BH3）、导热性能好的添加剂（如石墨烯）对其导热性能、吸放氢动力学和热力学性能的影响，并结合理论计算重点探究材料的导热性能与储氢性能之间的相关性，建立两者之间的关系模型，以寻找降低其可逆吸放氢温度和提高吸放氢反应速率的途径。运用导热系数测试仪、差示扫描量热仪和C80微量热仪等设备对所合成的材料体系进行导热系数、热容、焓、生成热等重要热力学参数进行研究，为新型储氢材料的研发提供系统的科学理论依据。

Due to its higher hydrogen capacity, Li-Mg-N-H system as hydrogen storage material was paid special attention by researchers all over the world. Now it has been one of the hot research fields in hydrogen storage materials. But this kind of hydrogen storage materials still have some drawbacks, such as poor mass and heat transfer for solid-solid reaction, higher temperature for hydrogen desorption, higher kinetic barrier for hydrogen absorption/desorption, poor reversibility for hydrogen absorption/desorption, and so on. In order to overcome the aforementioned problems, some light metals with different ion radius and electronegativity (Li, Na, K, Mg, Ca) or the additives (melted when heated) with good thermal conductivity (KNH2, NH3BH3, graphene) will be introduced in Li-Mg-N-H system. Combined with theoretical calculation (first-principle or DFT), the relationship between thermal conductivity and hydrogen storage properties will be focused on and the model between thermal conductivity and hydrogen storage properties will be established in order to find the strategy for decreasing temperature and increasing the reaction rate for reversible hydrogen absorption/desorption. And the thermal conductivity, formation heat and other thermodynamic parameters (Heat capacity, Enthalpy and so on) of as-prepared samples will be investigated systematically by means of the apparatus for thermal conductivity, TG/DSC and C80 micro-calorimeter. This project will bring further insights for developing new materials for hydrogen storage.