ZnMn_(2)O_(4)/Mn_(2)O_(3)/CNT复合正极材料的制备及其在水锌离子电池中的应用

Preparation of ZnMn_(2)O_(4)/Mn_(2)O_(3)/CNT composite cathode material and its application in aqueous zinc-ion batteries

以Zn(NO3)2·6H2O、Mn(AcO)2·4H2O和碳纳米管(CNT)为原料,经过表面活性剂辅助溶剂热反应合成了CNT包覆ZnMn2O4/Mn2O3(ZMO/MO)复合材料,通过XRD和SEM对材料的结构和形貌进行表征。结果表明,CNT均匀包覆在微球状ZMO/MO复合物的表面。在0.1A/g电流密度下,CNT包覆量为10%(即CNT质量占复合微球质量的百分数,下同)的ZMO/MO/10CNT复合材料放电比容量为112.8mA·h/g,并且在300次循环后仍能保持在49.6 mA·h/g的可逆比容量。在电流密度为0.1、0.2、0.4、0.8、1.2、2.0 A/g时,其放电比容量分别为126.2、124.4、115.4、94.2、57.3和45.0mA·h/g。采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。

Carbon nanotubes(CNT) coated ZnMn2O4/Mn2O3(ZMO/MO) composites were synthesized from Zn(NO3)2·6H2O, Mn(AcO)2·4H2O and CNT via a facile surfactant-assisted solvothermal method. The structure and morphology of the composites were characterized by XRD and SEM. The results showed that CNT was uniformly coated on the surface of microspherical ZMO/MO composites. The ZMO/MO composites with 10% CNT coated amount(the percentage of CNT mass in the composite microsphere mass,the same below) had a discharge specific capacity of 112.8 mA·h/g at 0.1 A/g current density, and it could still maintain the reversible capacity of 49.6 m A·h/g after 300 cycles. The discharge specific capacities corresponding to current densities of 0.1, 0.2, 0.4, 0.8, 1.2 and 2.0 A/g were 126.2, 124.4, 115.4, 94.2, 57.3 and 45.0 mA·h/g, respectively. The kinetics characteristics of the electrodes were investigated by cyclic voltammetry and electrochemical impedance. It was found that two-phase recombination increased Zn2+ diffusion rate, and the introduction of CNT improved charge transfer.