Abstract Mixed alkali alanates Li x Na 3-x AlH 6 have been successfully synthesized by means of grinding mixtures of Li 3 AlH 6 and Na 3 AlH 6 in specific molar ratios. Non-stoichiometric Li x Na 3-x AlH 6 compounds with single perovskite-type structures (space group Fm-3m) can be formed only within the composition range of x = 0.9–1.3. Li 1.3 Na 1.7 AlH 6 exhibits superior hydrogen storage properties over other Li x Na 3-x AlH 6 compounds. Its onset dehydrogenation temperature (∼423 K) was lowered by more than 40 K from other samples in temperature programmed dehydrogenation (TPD) curves. Also, the dehydrogenation capacity of Li 1.3 Na 1.7 AlH 6 (3.45 wt.%) is the highest among the compounds. The dehydrogenation enthalpy values of Li x Na 3-x AlH 6 decreased as x increased from 0.9 to 1.3 according to the results by isothermal pressure-composition (PCI) curves and van't Hoff plots. It shows that the dehydrogenation Li 1.3 Na 1.7 AlH 6 (49.7 kJ mol H 2 −1 ) was greatly destabilized from that of LiNa 2 AlH 6 (68.1 kJ mol H 2 −1 ). Furthermore, the apparent activation energy of dehydrogenation for Li 1.3 Na 1.7 AlH 6 (138.1 kJ mol −1 ) was remarkably lowered from that of LiNa 2 AlH 6 . This illustrates that Li 1.3 Na 1.7 AlH 6 exhibits enhanced dehydrogenation kinetics from that of LiNa 2 AlH 6 .

中文翻译：

---

Li x Na 3-x AlH 6 (x=0.9–1.3) 非化学计量化合物的制备和脱/再氢化性能

摘要 通过研磨特定摩尔比的Li 3 AlH 6 和Na 3 AlH 6 混合物，成功合成了混合碱金属铝氢化物Li x Na 3-x AlH 6 。具有单一钙钛矿型结构（空间群 Fm-3m）的非化学计量 Li x Na 3-x AlH 6 化合物只能在 x = 0.9–1.3 的组成范围内形成。Li 1.3 Na 1.7 AlH 6 表现出优于其他Li x Na 3-x AlH 6 化合物的储氢性能。在程序升温脱氢（TPD）曲线中，其起始脱氢温度（~423 K）比其他样品降低了 40 K 以上。此外，Li 1.3 Na 1.7 AlH 6 (3.45 wt.%)的脱氢能力在这些化合物中是最高的。Li x Na 3-x AlH 6 的脱氢焓值随着 x 从 0.9 增加到 1 而降低。3 根据等温压力-成分 (PCI) 曲线和范特霍夫图的结果。这表明脱氢 Li 1.3 Na 1.7 AlH 6 (49.7 kJ mol H 2 -1 ) 与 LiNa 2 AlH 6 (68.1 kJ mol H 2 -1 ) 的脱氢稳定性相差很大。此外，Li 1.3 Na 1.7 AlH 6 (138.1 kJ mol -1 )的表观脱氢活化能比LiNa 2 AlH 6 显着降低。这说明与LiNa 2 AlH 6 相比，Li 1.3 Na 1.7 AlH 6 表现出增强的脱氢动力学。1 kJ mol -1 ) 明显低于 LiNa 2 AlH 6 。这说明与LiNa 2 AlH 6 相比，Li 1.3 Na 1.7 AlH 6 表现出增强的脱氢动力学。1 kJ mol -1 ) 明显低于 LiNa 2 AlH 6 。这说明与LiNa 2 AlH 6 相比，Li 1.3 Na 1.7 AlH 6 表现出增强的脱氢动力学。