The research of high-performance cathode materials for rechargeable lithium-ion batteries (LIBs) is highly desirable. The ternary layered oxide LiNi1/3Co1/3Mn1/3O2 (LNCM) is a promising cathode material for LIBs due to its high discharge voltage, large specific capacity, good thermostability, and low cost. However, the LNCM cathode still has certain limitations, including cationic mixing and low electronic conductivity. These drawbacks ultimately result in poor cycling stability, rapid voltage degradation, and capacity loss during high-rate cycling. To address these issues, we have established a feasible sol-gel method combined with calcination to prepare LNCM, which can significantly improve the electrochemical activity of the LNCM cathode. The developed LNCM−850/10 cathode displays an initial specific discharge capacity of 215.3 mAh g−1 at a current rate of 0.2 C and retains a high reversible capacity of 93.9 mAh g−1 after 200 cycles. In addition, the LNCM−850/10 cathode also exhibits excellent high-rate charge-discharge capability and high-rate cycling performance. These remarkable results are probably due to the low Li+/Ni2+ cation mixing degree, good particle morphology, and uniform particle size distribution of LNCM−850/10, which effectively improves the electronic conductivity and lowers the charge transfer resistance, while reducing the Li+ diffusion distance and accelerating the insertion/extraction of Li+. Our study demonstrates that careful control of the calcination temperature of sol-gel-synthesized LNCM precursors can promote the development of LNCM cathodes suitable for advanced LIBs.