阴极
涂层
材料科学
电化学
表面改性
化学工程
氧化物
兴奋剂
钠
离子
电极
纳米技术
冶金
化学
有机化学
工程类
物理化学
光电子学
作者
Jun-zhou Wang,Yingxue Teng,Guan-qiao Su,Shuo Bao,Jinlin Lu
标识
DOI:10.1016/j.jcis.2021.11.028
摘要
P2-type materials are regarded as competitive cathodes for next generation sodium ion batteries. However, the unfavorable P2 → O2 phase transition usually leads to severe capacity decay. Moreover, the cathode material always suffers from destruction of surface crystal structure caused by trace amount of HF. In this study, a dual-modification method containing Mg/Ti co-doping and MgO surface coating is designed to solve the defects of P2-type Na0.67Ni0.17Co0.17Mn0.66O2 cathode. Results turn out that the P2 structure can be stabilized via Mg/Ti co-substitution and MgO layer could effectively prevent the surface from corroding by HF and promote migration of Na+. Moreover, the as-prepared MgO-coated Na0.67Ni0.17Co0.17Mn0.66Mg0.1O2 exhibits improved electrochemical performance than the raw material. It delivers 111.6 mAh g-1 initial discharge capacity and maintains 90.6% at high current density of 100 mA g-1 within 2-4.5 V, which has been obviously enhanced than that of Na0.67Ni0.17Co0.17Mn0.66O2. The significant improvement can be attributed to the synergistic effect of Mg/Ti co-substitution and MgO surface coating. This dual-modification strategy based on the synergetic effect of Mg/Ti co-doping and MgO surface coating might be a resultful step forward to develop cathode materials for sodium ion batteries.
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