Jiang Jun, Ouyang Liuzhang, Wang Hui, Liu Jiangwen, Shao Huaiyu, Zhu Min
School of Materials Science and Engineering, Guangdong Provincial Key Laboratory of Advanced Energy Storage Materials, South China University of Technology, Guangzhou, 510641, People's Republic of China.
China-Australia Joint Laboratory for Energy & Environmental Materials, Key Laboratory of Fuel Cell Technology of Guangdong Province, Guangzhou, 510641, People's Republic of China.
Chemphyschem. 2019 May 16;20(10):1316-1324. doi: 10.1002/cphc.201900058. Epub 2019 Apr 8.
Theoretically, the hydrolysis of MgLi and MgH -LiH can produce 9.6 and 17.5 wt.% hydrogen (water is not included in the calculation), respectively. The ball-milling method is commonly used to refine the particle size and thus may improve hydrolysis kinetics. However, Mg and Li will be easily agglomerated, which means that direct ball-milling could not refine MgLi. In this work, we introduced 10 wt.% expanded graphite into the ball-milling process to synthesize refined MgLi alloy samples. Further studies showed that MgLi-10 wt.% expanded graphite can produce 966 mL/g hydrogen within 3 min in 0.5 M MgCl solution. The MgLi hydrides were synthesized by reactive ball milling under 3 MPa H and their hydrolysis performance was investigated. Moreover, the sawed powder was milled in 3 MPa H for 6 h and then hydrogenated in 3 MPa H at 380 °C; it can produce 1542 and 1773 mL/g (15.8 wt.%) hydrogen in 5 and 30 min with mild kinetics, respectively, and the activation energy of the hydrolysis reaction is 24.6 kJ/mol in 1 M MgCl solution. The findings here open a new avenue to the development of refined MgLi alloys and hydrides for hydrogen generation through a controllable hydrolysis process.
理论上，MgLi和MgH -LiH的水解分别可产生9.6 wt.%和17.5 wt.%的氢气（计算中不包括水）。球磨法常用于细化粒径，从而可能改善水解动力学。然而，Mg和Li容易团聚，这意味着直接球磨无法细化MgLi。在本工作中，我们在球磨过程中引入10 wt.%的膨胀石墨来合成细化的MgLi合金样品。进一步研究表明，MgLi-10 wt.%膨胀石墨在0.5 M MgCl溶液中3分钟内可产生966 mL/g氢气。通过在3 MPa氢气下进行反应球磨合成了MgLi氢化物，并对其水解性能进行了研究。此外，将锯切粉末在3 MPa氢气中球磨6小时，然后在380°C下于3 MPa氢气中氢化；它在5分钟和30分钟内分别可产生1542和1773 mL/g（15.8 wt.%）氢气，水解动力学较为温和，在1 M MgCl溶液中水解反应的活化能为24.6 kJ/mol。此处的研究结果为通过可控水解过程开发用于制氢的细化MgLi合金和氢化物开辟了一条新途径。
