Abstract: A spray-drying method was developed to synthesize MnO₂ cathode materials and measurements of XRD,SEM and electrochemistry were performed to characterize the properties of the prepared materials.Experimental results showed that Mn₂O₃ was formed during heat-treating and changed to γ-MnO₂ after acid treating.The precursor had the shape of a globe, and then cracked when being sintered.The initial discharge capacity reached 215mAh·g^-1 and 70% DOD with respect to the first one-electron reduction of γ-MnO2.It could be higher by 15% than EMD.Combined with cathodic polarization and AC impedance, the finite diffusion model was used to interpret the proton diffusion inside the lattice of MnO₂.

摘要： 采用喷雾热解法制备了超细MnO₂阴极材料，并利用XRD、SEM和电化学测试方法研究了MnO₂的相组成、形貌、电化学性能以及在碱性溶液中的阴极极化行为.实验结果表明，喷雾干燥后的样品呈球形，表面有裂纹，经热处理后产物为Mn₂O₃，此时颗粒表面碎裂，形成多孔材料，酸处理后得到γ-MnO₂，含量超过90％.与EMD（电解二氧化锰）相比，所制备样品的放电容量（截止电压1.0V vs Zn）为215mAh·g^-1，放电深度可达一电子理论容量的70％，比EMD提高了15％;结合稳态极化和电化学阻抗法，发现质子在MnO₂晶格中的扩散符合多孔电极的阻挡层扩散模型，由等效电路拟合得到的数据能够较好地解释实验现象，反映了质子固相扩散的真实情况.