Gradient V2O5 surface-coated LiMn2O4 cathode towards enhanced performance in Li-ion battery applications

• Published in: Electrochimica acta Vol. 120; pp. 390 - 397
• Main Authors: Ming, Hai, Yan, Yuerong, Ming, Jun, Adkins, Jason, Li, Xiaowei, Zhou, Qun, Zheng, Junwei
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 20-02-2014
• Subjects: Cathode; Core@shell; LiMn2O4; Lithium battery; V2O5; Lithium battery; Core@shell; V2O5; Cathode; LiMn2O4
• ISSN: 0013-4686; 1873-3859
• DOI: 10.1016/j.electacta.2013.12.096

Gradient V2O5 surface-coated LiMn2O4 particles with size distribution of 100 - 500 nm and excellent performance in lithium-ion battery were prepared via a simple method, and the amount of V2O5-coating was initially proved to be a critical parameter for improving the properties of LiMn2O4.
•Gradient V2O5 surface-coated LiMn2O4 (LiMn2O4@V2O5) particles were prepared.•LiMn2O4 particles were coated by amorphous V2O5 layer (5 - 10nm) successfully.•The layer of V2O5 can improve physical and chemical properties of LiMn2O4.•LiMn2O4@V2O5 particles exhibit excellent performance in lithium-ion batteries.•The amount of V2O5-coating is a critical parameter for improving cathode properties.
The spinel LiMn2O4 was recognized as an appealing candidate cathode material for high rate Li-ion battery, but it suffers from severe capacity fading, especially at a high temperature. In order to solve this problem, we prepared V2O5 coated LiMn2O4 (LiMn2O4@V2O5) samples in this work and its structure and morphology were characterized by powder X-ray diffraction, scanning electron microscope, and transmission electron microscope. The LiMn2O4@V2O5 material delivers an excellent cycling ability and rate capability in lithium batteries, while sustaining a capacity of 75.5 mAh g−1 after 200 cycles at 2C with a high operating temperature (328K). This performance are much better than that of LiMn2O4 (35.4 mAh g−1) without V2O5 coating, the capacity of which faded seriously. These results indicated that the surface modification of V2O5, which possess a relative lower operating potential (≤ 3.7V, LixV2-x/5O5) compare to the LiMn2O4 (∼ 3.9 and 4.1V), can improve the electrochemical properties of LiMn2O4 by endowing a fast lithium diffusion and reasonable electronic conductivity which facilitates the transformation of the electrons and ions. In addition, the acidic and isolated protective layer of V2O5 can work as a HF inhibitor and/or HF scavenger and suppress the dissolution of manganese into electrolyte. Thus, we believe that such a LiMn2O4@V2O5 composite can be an economical and viable candidate cathode material for Li-ion batteries.