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γMnO2, 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.
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 215 mAh·g-1 and 70% DOD with respect to the first one-electron reduction of Y-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.
出处
《化工学报》
EI
CAS
CSCD
北大核心
2005年第5期925-931,共7页
CIESC Journal
基金
浙江省科技厅重大项目 (021101718)~~
关键词
喷雾热解法
超细二氧化锰
电化学性能
电化学阻抗
Cathodes
Characterization
Diffusion
Drying
Electric impedance
Electrochemistry
Heat treatment
Polarization
Powders
