锰氧化物正极材料的低温焙烧制备及电化学性能

Low-temperature roasting preparation and electrochemical properties of manganese oxide cathode materials

摘要:

以电解锰阳极泥（EMAM）为原料，利用焙烧活化法制备AZIBs锰氧化物正极材料，通过XRD、TGA、SEM以及电化学性能测试考察了氮气氛围下，不同焙烧温度（300、425、575 ℃）对锰氧化物正极材料的结构、形貌以及电化学性能的影响。结果表明，氮气氛围焙烧，提高了锰氧化物正极材料的衍射率和结晶度，材料呈现出片状和颗粒的形态，团聚现象减少，空隙增加；随着焙烧温度的提高，锰氧化物正极材料结构逐渐从α-MnO2转变为Mn2O3与Mn3O4；通过焙烧，锰氧化物正极材料的首次放电比容量、倍率性能和循环性能得到提升，材料具有较小的瓦尔堡系数和更快的Zn2+的扩散速度。其中，焙烧温度300 ℃制备的锰氧化物正极材料（300-EMAM）表现出更好的电化学性能，在5 C倍率下，300-EMAM的初始放电比容量为232 mA·h/g，循环100圈后仍能保持在190.0 mA·h/g的可逆比容量；300-EMAM电极具有较低的接触电阻（33.6 Ω）和电荷转移电阻（816.3 Ω）。

Abstract:

AZIBs manganese oxide cathode materials were prepared from electrolytic manganese anode mud (EMAM) by roasting activation method, and the effects of different roasting temperatures (300, 425 and 575 ℃) on the structure, morphology and electrochemical properties of the manganese oxide cathode materials under nitrogen atmosphere were investigated by XRD, TGA, SEM, and electrochemical performance tests. The results showed that the nitrogen atmosphere roasting improved the diffractivity and crystallinity of the manganese oxide cathode materials, and the materials showed the morphology of flakes and particles, the agglomeration phenomenon was reduced, and the voids were increased. The structure of the manganese oxide cathode materials was gradually transformed from α-MnO2 to Mn2O3 and Mn3O4 with the increase of the roasting temperature. Through the roasting, the specific capacity of the manganese oxide cathode materials in first discharge, the multiplicity performance and the first discharge specific capacity, multiplicity performance and cycling performance of the manganese oxide cathode material are improved, and the material has a smaller Vaalborg coefficient and a faster diffusion rate of Zn2+. Among them, the manganese oxide cathode material (300-EMAM) prepared at a roasting temperature of 300 ℃ showed better electrochemical performance, with an initial discharge specific capacity of 232 mA·h/g at a multiplication rate of 5 C. The reversible specific capacity of the 300-EMAM was maintained at 190.0 mA·h/g after 100 cycles; the 300-EMAM electrode had a lower contact resistance ( 33.6 Ω) and charge transfer resistance (816.3 Ω).