Surface modification on enhancing the high-voltage performance of LiNi0.8Co0.1Mn0.1O2 cathode materials by electrochemically active LiVPO4F hybrid

Abstract

Ni-rich LiNi0.8Co0.1Mn0.1O2 cathode material possesses advantages of high capacity and low cost, but the rapid capacity decline and power degradation during cycle process at high cut-off voltage limits its large-scale industrialization. Meanwhile, LiVPO4F modified with carbon based hybrid is relatively stable and has excellent electrochemical properties at higher cut-off voltage of 4.4–4.5 V. Based on the idea of secondary modification for cathode material, the LiVPO4F hybrid is used to modify LiNi0.8Co0.1Mn0.1O2 to obtain LiVPO4F-LiNi0.8Co0.1Mn0.1O2 composites. The presence of the LiVPO4F hybrid maintains interfacial stability, suppresses irreversible side reactions and sustains a relatively rapid charge transfer under high voltage. The LiVPO4F modified LiNi0.8Co0.1Mn0.1O2 composites delivers a discharge specific capacity of 140.0 mAh g−1 at high rate of 20 C, and achieves a cycle retention rate of 83.38% at 4.5 V after 150 cycles, revealing that good rate capability and cycling performance of LiNi0.8Co0.1Mn0.1O2 is improved-achieved by surface modification of LiVPO4F even at high cut-off voltage of 4.5 V.