Improved electrochemical performance of Li1.2Ni0.2Mn0.6O2 cathode material for lithium ion batteries synthesized by the polyvinyl alcohol assisted sol-gel method

Li-rich Mn-based cathode materials (Li1.2Ni0.2Mn0.6O2) have been synthesized by a polyvinyl alcohol (PVA)-assisted sol-gel method. The influence of PVA content on the structure and electrochemical performance of Li1.2Ni0.2Mn0.6O2 has been investigated respectively. XRD results of the Li1.2Ni0.2Mn0.6O2 powders show that they exhibit similar XRD patterns as those of Li-rich Mn-based cathode materials, and the crystalline nature of the layered compound are improved by the presence of PVA. Physical characterizations indicate that the as-synthesized oxide is composed of uniform and separated particles compared to the larged aggregated ones of the product synthesized under the same condition but without PVA. As cathode for lithium ion battery, the material synthesized with 10% PVA exhibits not only a relatively high discharge capacity of 254.2 mA h g−1, but also excellent rate performance and good cycling performance. EIS results show that the material synthesized with PVA decreases the charge-transfer resistance and enhances the reaction kinetics, which is considered to be the major factor for higher rate performance.