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在氩气气氛下,采用机械球磨法制备AlCl3掺杂的4MgH2-Li3AlH6储氢材料,研究AlCl3对4MgH2-Li3AlH6脱氢性能的影响。借助热重(TG)法研究了4MgH2-Li3AlH6-AlCl3体系的放氢性能,并运用X射线衍射(XRD)分析和差示扫描量热(DSC)法对其反应机理进行了探索。实验结果表明,加入AlCl3可有效增加4MgH2-Li3AlH6体系的反应活性,促进二者分解放氢,并降低该体系的放氢温度,增大总脱氢量。当AlCl3的掺杂量为4%(摩尔分数)、磨球24颗、球磨时间2.0h和转速541r/min时,4MgH2-Li3AlH6-AlCl3体系起始放氢温度降至130℃,比4MgH2-Li3AlH6体系降低了43℃;且400℃时总脱氢量从5.5%(质量分数)增加到6.3%(质量分数)。同时,机理研究表明:在球磨过程中部分Li3AlH6和AlCl3发生反应,产生了活性Al,进而改善了体系的放氢性能。
In argon atmosphere, AlCl3-doped 4MgH2-Li3AlH6 hydrogen storage material was prepared by mechanical ball milling to study the effect of AlCl3 on dehydrogenation performance of 4MgH2-Li3AlH6. The hydrogen evolution properties of 4MgH2-Li3AlH6-AlCl3 system were investigated by TG method. The reaction mechanism was investigated by X-ray diffraction (XRD) and differential scanning calorimetry (DSC). The experimental results show that the addition of AlCl3 can effectively increase the reactivity of 4MgH2-Li3AlH6 system, promote the decomposition and desorption of both, and reduce the dehydrogenation temperature of the system and increase the total amount of dehydrogenation. The initial hydrogen evolution temperature of 4MgH2-Li3AlH6-AlCl3 system dropped to 130 ℃ when the amount of AlCl3 doping was 4%, 24 balls, ball milling time 2.0h and rotational speed 541r / min, respectively. Compared with 4MgH2-Li3AlH6 The system is reduced by 43 ℃; and the amount of dehydrogenation at 400 ℃ from 5.5% (mass fraction) to 6.3% (mass fraction). At the same time, mechanism research shows that part of Li3AlH6 and AlCl3 react during milling to produce active Al, thus improving the hydrogen-releasing performance of the system.