Designing an advanced P2-Na0.67Mn0.65Ni0.2Co0.15O2 layered cathode material for Na-ion batteries

作者：Li Zheng Yao; Gao Rui; Sun Limei; Hu Zhongbo; Liu Xiangfeng

来源：Journal of Materials Chemistry A, 2015, 3(31): 16272-16278.

DOI：10.1039/c5ta02450a

A high performance layered P2-Na0.67Mn0.65Ni0.2Co0.15O2 cathode material for sodium ion batteries with high rate capability and excellent long-life cyclic performance has been successfully designed and synthesized by a simple sol-gel method. In comparison with the reported Na0.7MnO2, the designed P2-Na0.67Mn0.65Ni0.2Co0.15O2 cathode material can be charged and discharged in an extended voltage range of 1.5-4.2 V and shows reversible capacities of 155, 144, 137, 132 and 126 mA h g(-1) at different current densities of 12, 24, 48, 120 and 240 mA g(-1), respectively. Even at high current densities of 480 (2C), 1200 (5C) and 1920 mA g(-1) (8C) it can still deliver capacities of 117, 93 and 70 mA h g(-1), respectively, which are much higher than those of the recently reported Na-0.5[Ni0.23Fe0.13Mn0.63]O-2. In addition, the Na0.67Mn0.65Ni0.2Co0.15O2 cathode material also displays an excellent capacity retention ca. 85% and 78% after 100 cycles at 0.05C and 0.5C, respectively. It is also proposed that Mn4+ may be "activated" in a low voltage range, especially below 2.0 V, which contributes to the additional capacity. The Na-ion diffusion coefficient, DNa+, is ca. 10(-14) cm(2) s(-1) as calculated by the PITT and the discharge diffusion coefficient is a little larger than the charge one. The designed Na0.67Mn0.65Ni0.2Co0.15O2 shows great potential as a cathode material for sodium ion batteries.

• 出版日期2015
• 单位中国科学院大学; 中国原子能科学研究院