Effects of the nanostructured SiO2 coating on the performance of LiNi0.5Mn15O4 cathode materials for high-voltage Li-ion batteries

• Published in: Electrochimica acta Vol. 52; no. 11; pp. 3870 - 3875
• Main Authors: Fan, Yukai, Wang, Jianming, Tang, Zheng, He, Weichun, Zhang, Jianqing
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier 01-03-2007
• Subjects: Applied sciences; Direct energy conversion and energy accumulation; Electrical engineering. Electrical power engineering; Electrical power engineering; Electrochemical conversion: primary and secondary batteries, fuel cells; Exact sciences and technology; LiF; X ray; Electrode material; Non metal coating; Silica; Photoelectron spectrometry; XPS; Electrical characteristic; Surface modification; Cathode; Lithium fluoride; Fumed silica; Secondary cell; Nanostructure; Surface treatment; Manganese oxides; High voltage; Spinels; Lithion ion batteries; Lithium oxide; Performance; Nanostructured materials; LiNi0.5Mn1.5O4 spinel; Specific capacity; Nickel oxide
• ISSN: 0013-4686; 1873-3859
• DOI: 10.1016/j.electacta.2006.10.063

LiNi0.5Mn1.5O4 spinels coated with various amounts of fumed silica have been synthesized and investigated as cathode materials for high-voltage lithium-ion batteries at the elevated temperature (55 deg C). The morphology and structure of the coated LiNi0.5Mn1.5O4 samples were characterized by XRD, TEM and EDX. It was found that the surfaces of the coated LiNi0.5Mn1.5O4 samples are covered with a porous, amorphous, nanostructured SiO2 layer. The results of electrochemical experiments showed that the SiO2-coated LiNi0.5Mn1.5O4 samples display obviously improved capacity retention rate, and the improvement effect enhances with the increase of SiO2 content. The XPS results revealed that the surfaces of the SiO2-coated LiNi0.5Mn1.5O4 cathode materials have relatively low content of LiF, and this is mainly responsible for their improved electrochemical cycling stability.