School of Materials Science and Engineering, Hebei University of Technology, Tianjin300130, China.
Key Laboratory of Special Functional Materials for Ecological Environment and Information (Hebei University of Technology), Ministry of Education, Tianjin300130, China.
ACS Appl Mater Interfaces. 2023 Jan 11;15(1):1418-1431. doi: 10.1021/acsami.2c20224. Epub 2022 Dec 23.
In order to alleviate the rapid capacity decay caused by the instability of the crystal structure and electrode/electrolyte interface, a series of LiSiO-coated LiNiMnO materials have been prepared via the lithium acetate-assisted sol-gel method followed by a short-term calcination process. During the sol-gel process, TEOS is hydrolyzed, condensed, and polymerized with the assistance of lithium acetate to form a Li-embedded [Si-O-Si] network structure to ensure the uniformity of the coating. By changing the amount of TEOS and lithium acetate, the coating thickness can be precisely controlled, whose effects on the structural and electrochemical properties of LiNiMnO materials are intensively investigated. The results show that the material with an appropriate thickness of LiSiO coating exhibits a larger primary particle size and reduced secondary particle agglomeration. The uniform LiSiO coating with appropriate thickness can not only improve Li ion diffusion kinetics but also suppress side reactions and CEI growth at the electrode/electrolyte interface. Besides, the interaction of LiSiO with HF can alleviate electrode corrosion and the dissolution of transition metal ions. All the abovementioned factors together promote the significant improvement of the electrochemical performance of LiSiO-coated LiNiMnO materials.
为了缓解晶体结构和电极/电解质界面不稳定性导致的容量快速衰减，通过乙酸锂辅助的溶胶-凝胶法和短时间的煅烧过程，制备了一系列 LiSiO 包覆的 LiNiMnO 材料。在溶胶-凝胶过程中，TEOS 在乙酸锂的协助下水解、缩合和聚合，形成嵌入 Li 的[Si-O-Si]网络结构，以确保涂层的均匀性。通过改变 TEOS 和乙酸锂的用量，可以精确控制涂层厚度，深入研究了其对 LiNiMnO 材料结构和电化学性能的影响。结果表明，具有适当厚度 LiSiO 涂层的材料具有更大的一次颗粒尺寸和减少的二次颗粒团聚。具有适当厚度的均匀 LiSiO 涂层不仅可以提高锂离子扩散动力学，还可以抑制电极/电解质界面处的副反应和 CEI 生长。此外，LiSiO 与 HF 的相互作用可以减轻电极腐蚀和过渡金属离子的溶解。所有这些因素共同促进了 LiSiO 包覆的 LiNiMnO 材料电化学性能的显著改善。
