P2-Na 2/3 Ni 2/3 Te 1/3 O 2 Cathode for Na-ion Batteries with High Voltage and Excellent Stability

Energy & Environmental Materials

article

Wenhui Wang¹  Jiaolong Zhang³  Chaolin Li¹  Xiaohang Kou¹  Baohua Li⁴  Denis Y. W. Yu² 

[1] School of Civil and Environmental Engineering, Harbin Institute of Technology;School of Energy and Environment, City University of Hong Kong;School of Materials Science and Engineering, Dongguan University of Technology;Shenzhen Key Laboratory on Power Battery Safety Research and Shenzhen Geim Graphene Center, Tsinghua Shenzhen International Graduate School

关键词: air stability;    cathode;    Na2Ni2TeO6;    Na-ion battery;    oxygen redox reaction;    P2 structure;   

DOI  :  10.1002/eem2.12314

来源: Wiley

【 摘 要 】

Air-stable layered structured cathodes with high voltage and good cycling stability are highly desired for the practical application of Na-ion batteries. Herein, we report a P2-Na2/3Ni2/3Te1/3O2 cathode that is stable in ambient air with an average operating voltage of ~3.8 V, demonstrating excellent cycling stability with a capacity retention of more than 92.7% after 500 cycles at 20 mA g−1 and good rate capability with 91.9% capacity utilization at 500 mA g−1 with respect to capacity at 5 mA g−1 between 2.0 and 4.0 V. When the upper cutoff voltage is increased to 4.4 V, P2-Na2/3Ni2/3Te1/3O2 delivers a reversible capacity of 71.9 mAh g−1 and retains 91.8% of the capacity after 100 cycles at 20 mA g−1. The charge compensation during charge/discharge is mainly due to the redox couple of Ni2+/Ni3+ in the host with a small amount of contribution from oxygen. The stable structure of the material without phase transformation and with small volume change during charge-discharge allows it to give excellent cycle performance especially when the upper cutoff voltage is not higher than 4.2 V.

【 授权许可】

Unknown