He Shanshan, Li Leilei, Wu Yijin, He Shan, Guo Donghui
School of Electronic Science and Engineering, Xiamen University, Xiamen, Fujian 361005, China.
College of R&D Center of Integrated Circuit, Xiamen University, Xiamen, Fujian 361005, China.
J Chem Phys. 2024 Sep 21;161(11). doi: 10.1063/5.0219080.
When chloroaluminate (AlCl4-) serves as the electrolyte, aluminum nitride (AlN) has shown promise as a cathode material in aluminum ion batteries. However, there is currently a lack of research on the mechanisms of charge transfer and cluster intercalation between AlCl4 and AlN cathode materials. Herein, first-principles calculations are employed to investigate the intercalation mechanism of AlCl4 within the AlN cathode. By calculating the formation energies of stage-1-5 AlN-AlCl4 intercalation compounds with the insertion of individual AlCl4 cluster, we found that the structure of the stage-4 intercalation compounds exhibits the highest stability, suggesting that when the clusters begin to intercalate, it is important to start with the formation of the stage-4 intercalation compounds. In the subsequent phases of the charging process (stages 1 and 2), the stabilized structure with four inserted clusters demonstrates two characteristics: the coexistence of standing and lying clusters and the insertion of two standing clusters in an upside-down doubly stacked configuration, which further improve the spatial utilization while maintaining the structural stability. In addition, we infer that a phenomenon of coexisting intercalation compounds with mixed stages will occur in the course of the charging and discharging processes. More importantly, the diffusion barrier of AlCl4 in AlN-AlCl4 intercalation compounds decreases with the reduction of stage number, ensuring the rate performance of batteries. Therefore, we expect that our work will contribute to comprehend the intercalation mechanism of AlCl4 into the AlN cathode materials of aluminum ion batteries, providing guidance for related experimental work.
当氯铝酸盐（AlCl4-）用作电解质时，氮化铝（AlN）在铝离子电池中作为阴极材料展现出了潜力。然而，目前对于AlCl4与AlN阴极材料之间的电荷转移和团簇嵌入机制缺乏研究。在此，采用第一性原理计算来研究AlCl4在AlN阴极中的嵌入机制。通过计算单个AlCl4团簇插入时1-5阶段AlN-AlCl4嵌入化合物的形成能，我们发现4阶段嵌入化合物的结构表现出最高的稳定性，这表明当团簇开始嵌入时，首先形成4阶段嵌入化合物很重要。在充电过程的后续阶段（1和2阶段），具有四个插入团簇的稳定结构表现出两个特征：直立团簇和平躺团簇共存，以及两个直立团簇以倒置的双层堆叠构型插入，这在保持结构稳定性的同时进一步提高了空间利用率。此外，我们推断在充放电过程中会出现混合阶段的嵌入化合物共存现象。更重要的是，AlCl4在AlN-AlCl4嵌入化合物中的扩散势垒随着阶段数的减少而降低，确保了电池的倍率性能。因此，我们期望我们的工作将有助于理解AlCl4嵌入铝离子电池AlN阴极材料的机制，为相关实验工作提供指导。
