Li[Li0.2Mn0.54Ni0.13Co0.13]O2–LiMn1.5Ti0.5O4 composite cathodes with improved electrochemical performance for lithium ion batteries

• Published in: Electrochimica acta 2014-07, Vol.133, p.100-106
• Main Authors: Wang, Sihui, Wu, Yan, Li, Yixiao, Zheng, Jianming, Yang, Jihui, Yang, Yong
• Format: Article
• Language: English
• Subjects: Composite cathode; cycle life; irreversible capacity loss; lithium ion battery; rate capability
• ISSN: 0013-4686; 1873-3859
• DOI: 10.1016/j.electacta.2014.04.008

Layered Li[Li0.2Mn0.54Ni0.13Co0.13]O2–Spinel LiMn1.5Ti0.5O4 composite cathodes have been prepared by mechanically mixing process and investigated in this work. The unoccupied 16c sites of spinel LiMn1.5Ti0.5O4 can be used as a reservoir to store the Li+ ions that are lost during the activation of Li2MnO3 component in lithium-rich Li[Li0.2Mn0.54Ni0.13Co0.13]O2 material. As a consequence, the initial irreversible capacity loss (ICL) of lithium-rich Li[Li0.2Mn0.54Ni0.13Co0.13]O2 is significantly reduced in the presence of spinel LiMn1.5Ti0.5O4. When mixed with 35.7 wt% of LiMn1.5Ti0.5O4, the lithium-rich material shows an initial ICL of only 17 mAh g−1, and could still deliver an initial discharge capacity as high as 220 mAh g−1. More importantly, the composite materials show better cycling performance and rate capability as compared with the pristine Li[Li0.2Mn0.54Ni0.13Co0.13]O2. The material with 35.7 wt% LiMn1.5Ti0.5O4 shows the best cycling stability, retaining 90% of the initial discharge capacity at the current density of 20mAg−1 after 40 cycles. The improved cycling stability and rate performance can be ascribed to the good conductivity of spinel LiMn1.5Ti0.5O4 with 3D fast Li+ diffusion path, which ensures the timely lithium ion intercalation and de-intercalation.