High-nickel material has high theoretical capacity, which can be used for promoting the energy density of LIBs. As a type of high-nickel material, LiNi0.8Co0.1Mn0.1O2 has been widely researched. Nevertheless, to pursuit higher energy density, the study on ultra-high-nickel materials (MN>88%) is necessary. Unfortunately, the high content of Ni not only promotes the theoretical capacity, but also causes negative effects on the structure stability of high-nickel materials, which inhibits the practical application of high-nickel materials. Therefore, the preparation technology of ultra-high-nickel materials is significant. Herein, we prepared ultra-high-nickel materials with Ni content of 88%, 90%, 92%, 94%, and 98%, then the relevant physiochemical properties as well as electrochemical performances were investigated. The effects of the increased Ni content on the capacity and the structural stability of high-nickel materials were verified. Furthermore, the ultra-high-nickel material with Ni content of 90% (Ni90) was selected, and the effect of different sintering temperatures was evaluated. It was found that the particle sizes increased as thewith rising temperature, and 750℃ leads led to the best rate and cycling performances of Ni90, in which the particle sizes and the structural stability achieved a balance. Meanwhile, it was revealed that an appropriate sintering temperature was crucial to prepare ultra-high-nickel materials which exhibited both excellent performances and stability.