ZnMn2O4/Mn2O3/CNT复合正极材料的制备及其在水系锌离子电池的应用

The preparation of ZnMn2O4/Mn2O3/CNT composite cathode material and its application in Aqueous Zinc-ion Batteries

摘要:

锰基化合物具备高容量、高能量密度和高工作电压等特性，是水系锌离子电池（AZIBs）商业应用过程中的首选正极材料。然而，材料存在的电导率低、锰溶解、静电斥力效应和结构稳定性差等缺点，严重阻碍其大规模应用。采用表面活性剂辅助溶剂热法成功合成了碳纳米管（CNT）包覆ZnMn2O4/Mn2O3（ZMO/MO）复合材料，并探究了CNT包覆量对材料电化学性能和动力学过程的影响。采用X射线衍射和扫描电子显微镜对材料的结构和形貌进行表征。与纯相ZMO/MO相比，经CNT包覆的正极在0.1 A g-1电流密度下具有良好的循环稳定性和更高的倍率性能。并用循环伏安曲线和电化学阻抗探究了电极的动力学特性，两相复合提高了Zn2 扩散速率，CNT的包覆改善了材料的电荷传递。

Abstract:

Manganese based compounds with high capacity, high energy density and high operating voltage are the preferred cathode materials in the commercial application of Aqueous Zinc-ion Batteries (AZIBs). However, the low conductivity, manganese dissolution, effect of electrostatic repulsion and poor structural stability of the materials seriously hinder their large-scale application. Carbon nanotubes (CNT) coated ZnMn2O4/Mn2O3 (ZMO/MO) composites were successfully synthesized via a facile surfactant-assisted solvothermal method, and the effects of CNT coating amount on the electrochemical performance and kinetic process of the materials were investigated. The structure and morphology of the materials were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Compared with pure ZMO/MO, the CNT coated cathode has better cycle stability and higher rate performance at 0.1 A g-1 current density. The kinetics characteristics of the electrode were investigated by cyclic voltammetry and electrochemical impedance. The diffusion rate of Zn2 was increased by Biphasic composites, and the charge transfer was improved by CNT coating.