摘要
采用计时电流法沉积纳米Mn O2电极材料,利用Scharifker-Hills成核理论模型分析时间-电流(i-t)曲线判断了Mn O2成核机理。对3种不同的成核方式制得的Mn O2材料进行电化学超级电容性能测试、用SEM观察了其微观形貌。比较了不同沉积方法对沉积材料结构、电容性能的影响。计时电流测试发现,在0.1 mol/L Mn2+溶液中,电势阶跃至0.365 V,初始成核符合瞬时成核机理,在0.01 mol/L Mn2+溶液中,电势阶跃至0.418 V,初始成核存在瞬时成核和连续成核两种不同机理,在0.5 mmol/L Mn2+溶液中,电势阶跃至0.515 V,初始成核则符合连续成核机理。超级电容性能测试发现,瞬时成核下制得的Mn O2电极材料相对于另外两种成核方式得到的电极材料具有更好的电容性能,这是因为瞬时成核更易于形成多孔、纳米片(棒)状等高比表面积的沉积物,表明制备方法影响Mn O2电极材料电容性能。
An ITO supported nanostructure manganese dioxide thin film electrode, fabricated by chronoamperometry was evaluated as a potential electrode for electrochemical capacitors. The nucleation mechanism was examined by fitting the experimental data（chronoamperometry） into the Scharifker/Hills nucleation models. SEM images of the electrodeposits show that the microstructure of manganese dioxide is affected by the deposition period. The capacity of the three kinds of manganese dioxide electrode materials formed by different nucleation mechanisms was investigated by cycle voltammetry, constant current charge-discharge method and AC impedance. The results show that the nucleation follows an instantaneous nucleation mechanism in the solution of 0.1 mol/L Mn2＋ under a 0.365 V step potential, and mixed instantaneous and progressive nucleation mechanism in the solution of 0.01 mol/L Mn2＋ under a 0.418 V step potential. The nucleation follows a progressive nucleation mechanism in the solution of 0.5 mmol/L Mn2＋ under a 0.515 V step potential. It is obvious that the instantaneous nucleation is beneficial to preparing deposit sediment which has high specific surface area. Compare with other electrolytic deposit materials, this kind of material displays a better capacitance performance, implying that the capacitance performance can be influenced via different deposit approaches.
出处
《应用化学》
CAS
CSCD
北大核心
2015年第9期1081-1087,共7页
Chinese Journal of Applied Chemistry
基金
国家自然科学基金项目(21003163)
中央高校基本科研业务费科研专项(106112013025)
重庆大学SRTP资金资助项目(CQUSRTP-2014378)资助~~
关键词
二氧化锰
电化学沉积
成核机理
超级电容
manganese dioxide
electrodeposition
nucleation mechanism
supercapacitor
