Hybrid LiV 3 O 8 /carbon encapsulated Li 1.2 Mn 0.54 Co 0.13 Ni 0.13 O 2 with improved electrochemical properties for lithium ion batteries

• Published in: RSC advances Vol. 6; no. 34; pp. 28729 - 28736
• Main Authors: Sun, Kailing, Peng, Can, Li, Zhaohui, Xiao, Qichang, Lei, Gangtie, Xiao, Qizhen, Ding, Yanhuai, Hu, Zhongliang
• Format: Journal Article
• Language: English
• Published: 2016
• ISSN: 2046-2069; 2046-2069
• DOI: 10.1039/C6RA02688E

A low coulombic efficiency in the first cycle and poor rate capability limit the practical application of a lithium rich manganese-based solid solution (LMSS) in lithium ion batteries. To resolve these problems, a core–shell type of Li 1.2 Mn 0.54 Co 0.13 Ni 0.13 O 2 @LiV 3 O 8 /C (LMSSVC) composite material was prepared using a sol–gel process, in which NH 4 VO 3 -derived V 2 O 5 chemically leached lithium from the LMSS and formed the LiV 3 O 8 during high temperature annealing. The effect of the hybrid LiV 3 O 8 /C layer on the electrochemical properties of the LMSS is investigated using cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic charge–discharge measurements. The as-prepared LiV 3 O 8 nanoparticles are embedded within the carbon matrix uniformly, which becomes an outer shell to encapsulate the LMSS nanoparticles. Because of the Li-host nature of LiV 3 O 8 and the electronic conductivity of carbon, the LMSSVC can deliver a capacity of 269 mA h g −1 at a 0.1C rate in the first cycle over the voltage range of 2.0–4.8 V together with a coulombic efficiency of 94%, and retain 94% of the initial capacity after 50 cycles. It can deliver capacities of 258, 245, 229, 207 and 176 mA h g −1 at the rates of 0.2C, 0.5C, 1C, 2C and 5C, respectively. The results indicate that surface coating of the hybrid LiV 3 O 8 /C layer can improve not only the initial coulombic efficiency but also the rate capability of the LMSS material.