Outstanding Electrochemical Performance of Ni-Rich Concentration-Gradient Cathode Material LiNi(0.9)Co(0.083)Mn(0.017)O(2) for Lithium-Ion Batteries

The full-concentrationgradient LiNi(0.9)Co(0.083)Mn(0.017)O(2) (CG-LNCM), consisting of core Ni-rich LiNi(0.93)Co(0.07)O(2), transition zone LiNi(1−x−y)Co(x)Mn(y)O(2,) and outmost shell LiNi(1/3)Co(1/3)Mn(1/3)O(2) was prepared by a facile co-precipitation method and high-temperature calcination. CG-LNCM was then investigated with an X-ray diffractometer, ascanning electron microscope, a transmission electron microscope, and electrochemical measurements. The results demonstrate that CG-LNCM has a lower cation mixing of Li(+) and Ni(2+) and larger Li(+) diffusion coefficients than concentration-constant LiNi(0.9)Co(0.083)Mn(0.017)O(2) (CC-LNCM). CG-LNCM presents a higher capacity and a better rate of capability and cyclability than CC-LNCM. CG-LNCM and CC-LNCM show initial discharge capacities of 221.2 and 212.5 mAh g(−1) at 0.2C (40 mA g(−1)) with corresponding residual discharge capacities of 177.3 and 156.1 mAh g(−1) after 80 cycles, respectively. Even at high current rates of 2C and 5C, CG-LNCM exhibits high discharge capacities of 165.1 and 149.1 mAh g(−1) after 100 cycles, respectively, while the residual discharge capacities of CC-LNCM are as low as 148.8 and 117.9 mAh g(−1) at 2C and 5C after 100 cycles, respectively. The significantly improved electrochemical performance of CG-LNCM is attributed to its concentration-gradient microstructure and the composition distribution of concentration-gradient LiNi(0.9)Co(0.083)Mn(0.017)O(2). The special concentration-gradient design and the facile synthesis are favorable for massive manufacturing of high-performance Ni-rich ternary cathode materials for lithium-ion batteries.