铜元素掺杂改性蜂窝层状Na_(3)Ni_(2)SbO_(6)正极材料的电化学性能  

Electrochemical properties of copper doped honeycomb-layered Na_(3)Ni_(2)SbO_(6) cathode materials

作　　者：陈林 黄群[1] 陈铖 冯伊铭 韦伟峰[1] CHEN Lin;HUANG Qun;CHEN Cheng;FENG Yiming;WEI Weifeng(State Key Laboratory of Powder Metallurgy,Central South University,Changsha 410083,China)

机构地区：[1]中南大学粉末冶金国家重点实验室,长沙410083

出　　处：《粉末冶金材料科学与工程》2023年第1期9-19,共11页Materials Science and Engineering of Powder Metallurgy

基　　金：国家自然科学基金资助项目(51971250,11874199);湖南省科技创新计划资助项目(2021RC1001);中南大学粉末冶金国家重点实验室资助项目。

摘　　要：采用Cu部分替代Ni的方法对蜂窝层状Na_(3)Ni_(2)SbO_(6)正极材料进行掺杂改性,得到Na_(3)Ni_(2-x)CuxSbO_(6)(x=0、0.2、0.4、0.8)正极材料,利用X射线衍射仪和扫描电镜研究材料的形貌与结构,并测试其电化学性能。结果表明,Cu掺杂可以有效改善Na_(3)Ni_(2)SbO_(6)正极材料的循环稳定性,在0.1 C倍率下循环100圈后,Na_(3)Ni_(2)SbO_(6)的放电比容量仅为39.5 mA·h/g,而Na_(3)Ni_(1.8)Cu_(0.2)SbO_(6)材料的放电比容量达到72.3 mA·h/g。通过理论计算和实验分析发现,Cu(Ⅱ)的引入可有效缩小Na_(3)Ni_(2)SbO_(6)层状正极材料的带隙,降低Na+的扩散能垒,提高材料的电子电导和离子扩散速率,并且Cu掺杂可抑制Na_(3)Ni_(2)SbO_(6)正极材料在循环过程中发生不利相变,从而提高材料的循环稳定性和电化学性能。Honeycomb layered Na_(3)Ni_(2)SbO_(6)cathode materials were doped with Cu instead of Ni to obtain Na_(3)Ni_(2-x)CuxSbO_(6)(x=0,0.2,0.4,0.8)cathode materials.The morphology,structure and electrochemical properties of the materials were investigated by X-ray diffract to meter and scanning electron microscope.The results show that the cycling stability of Na_(3)Ni_(2)SbO_(6)cathode materials can be greatly enhanced by Cu substitution,i.e.the Cu-doped Na_(3)Ni_(1.8)Cu_(0.2)SbO_(6)materials display a discharge capacity of 72.3 mA·h/g after cycled for 100 cycles at 0.1C rate,while the discharge capacity of pristine Na_(3)Ni_(2)SbO_(6)cathode is only 39.5 m A·h/g under the same situation.Through theoretical calculation and experimental analysis,it is found out that the introduction of Cu(Ⅱ)can effectively reduce the band gap of Na_(3)Ni_(2)SbO_(6)layered cathode materials and the diffusion energy barrier of Na+,and improve the electronic conductivity and ion diffusion performance of the cathode materials,and Cu substitution can also inhibit the adverse phase change of Na_(3)Ni_(2)SbO_(6)cathode materials during the cycle,thus improving the cycle stability and electrochemical performance of the layered cathode materials.

关 键 词：正极材料 比容量 相变 循环稳定性 电化学性能 

分 类 号：TM925[电气工程—电力电子与电力传动]