Synthesis and Electrochemical Performances of the High Nickel Content Layer-Structured Cathode Materials for High-Energy Libs

Abstract

Among the various cathode candidate, layer structured Li(Ni,Co,Mn)O2 (NCM) has been regarded as the most attractive alternative to LIBs owing to relatively modest volume change (LiCoO2), high specific capacity (LiNiO2) and good thermal stability (LiMn2O4). Although Li(Ni1/3Co1/3Mn1/3)O2 has been successfully commercialized as a battery cathode, researches on Ni-rich NCM (LiNixCoyMn1−x−yO2, x > 0.5) have been spotlighted due to its superior capacity (> 200 mAh/g, at 4.6 V vs. Li/Li+) [10]. Therefore, the future of NCM for high energy LIBs strongly depends on Ni-rich NCM materials. It is reported that crystallinity and morphology, influenced by the sintering temperatures, all play important roles in the electrochemical performances. In this paper, we report the synthesis of LiNi0.91Co0.06Mn0.03O2 cathode materials with different sintering temperatures. Also the relationship between the sintering temperatures and the electrochemical performances is investigated. The sintering temperatures affect a crystallinity and morphology, which play an important role in electrochemical performances of LiNi0.91Co0.06Mn0.03O2. The electrochemical performances have improved with increasing sintering temperatures. The LiNi0.91Co0.06Mn0.03O2 sintered at 720 oC shows remarkably excellent performance: initial discharge capacity: 100 mAh/g, cycle performance: 98 % retention after 100 cycles (at 0.5 C) and rate capability: 88 % (at 2 C). These results indicate that LiNi0.91Co0.06Mn0.03O2 can be regarded as a next generation cathode for high-performance lithium ion batteries.