Triple effects of Sn-substitution on Na_0.67Ni_0.33Mn_0.67O₂

Xiaohui Rong，Fei Gao，Feixiang Ding，Yaxiang Lu，Kai Yang，Hong Li，Xuejie Huang，Liquan Chen，Yong-Sheng Hu

State Key Laboratory of Operation and Control of Renewable Energy and Storage Systems, China Electric Power Research InstituteKey Laboratory for Renewable Energy, Beijing Key Laboratory for New Energy Materials and Devices, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of SciencesCenter of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences

摘 要：Layered oxides are one of the most promising cathode materials for sodium ion batteries（NIBs）, however,the relatively low working voltage hinders the increase of energy density thus limiting the application scenarios of NIBs. Here we prepared and investigated a series of Sn⁴⁺ substituted Na_0.67Ni_0.33Mn_0.67-_xSn_xO₂（x = 0.10, 0.20, 0.30, 0.33） and found that Sn-substitution can induce three effects: promoting O3-stack formation, smoothing the voltage profile and increasing the working voltage to ～3.6 V. This study would enrich the knowledge of Sn-substitution and give guide to the better design of high-voltage cathode materials for NIBs.

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