阳离子稳定法可控制备双3D结构δ-MnO2薄膜电极及其赝电容特性

Manganese ore reserves in Guangxi rank first in China. The effective utilization and development of manganese resources plays an important role in promoting the economic development of Guangxi. Manganese oxide is considered as a favorable electrode material for use in supercapacitros due to its natural abundance, low cost and environmental compatibility. However, its relatively low specific capacitance limits its further advancements. Based on our previous study of successfully preparing α-MnO2 film electrode, this project will be a systematic study of controlled synthesis of double 3D(three-dimensional) δ-MnO2 film electrode by cationic stabilized method.The effect of the double 3D structure and selected addition of cations in the synthesis process on the pseudocapacitive behaviours of the film electrode will be the main area of study. The former would facilitate the penetration of electrolytes into all of the active materials and shorten the ion/electron diffusion distance during the electrochemical reaction, and the lattter would increase the interlayer spacing of MnO2. The Ardizzone model will be applied to investigate the storage mechanism and quantitatively determine the effect of surface chemisorption mechanism (SCM) and tunnel storage mechanism (TSM) on comprehensive electrochemical performance. The formation process and the effect on the electrochemical properties of the interface layer between the film prepared from the hydrothermal method and the substrate will be investigated. These can provide guidance for optimization of the synthesis parameters and then provide a new approach to developing a new type of supercapacitor with low cost and high quality.

广西锰矿保有储量居全国首位，锰资源的有效开发与利用对于促进广西经济发展具有重要的意义。作为超级电容器的电极材料，氧化锰具有储量丰富、价廉、环境友好等优点。但是，目前氧化锰电极较低的比容量限制了它的发展。在我们前期成功制备出α-MnO2薄膜电极的基础上，本课题拟系统研究阳离子稳定法可控制备超级电容器用双三维（3D）δ-MnO2薄膜电极。侧重对双三维的结构因增加活性物质与电解液的接触面积和减小电化学反应过程中离子/电子的传输距离、以及因加入选择性阳离子增加层间距，与MnO2薄膜电极超级电容特性的影响。应用Ardizzone模型对δ-MnO2的储能机理进行分析，定量分析表面吸附机理（SCM）及隧道储能机理（TSM）对其电化学性能的综合影响；研究水热条件下制备的薄膜与基底间的结合力及界面层的形成过程及对其电化学性能的影响，为优化合成参数提供指导，并最终为发展新型低成本高质量超级电容器提供新的解决办

超级电容器又称电化学电容器，是一种介于传统电容器和电池之间的新型储能元件，在移动通讯、消费电子、电动汽车等方面有着极其重要和广阔的应用前景。项目执行期间主要进行了双三维结构δ-MnO2薄膜电极的制备及其超级电容特性的研究。.1.以高锰酸钾与十二烷基硫酸钠为原料，水热法制备氧化锰薄膜的体系中加入一定量的金属离子盐（钾盐、钠盐、钙盐、铝盐等）后发现，阳离子模板剂的加入确实可以对所得薄膜的晶型进行控制：没另加入阳离子模板的体系中，水热1.5-6小时所获得的薄膜都为α型MnO2；，而加入了一定量阳离子模板剂后，体系在水热1.5-5小时所得到的薄膜都为δ型MnO2，但如果水热延长至6小时，薄膜仍就转化为了α型MnO2。这一结果说明在水热条件下δ-MnO2的确是α-MnO2的中间相，而且通过外加入足够的阳离子模板是有可能对介稳状态的δ-MnO2进行稳定的，也即采用阳离子稳定法是有可能制备δ-MnO2薄膜的。.2. 此外，外加不同的阳离子模板剂可以对δ-MnO2的层间距进行调控，如加入水合离子直径较大的Al3+或Ca2+所得δ-MnO2的层间距要比以Na+和K+为阳离子模板剂的有所增大（加入Na+、K+ 、Ca2+和Al3+模板剂后所得氧化锰的层间距分别为7.11Å、7.10Å、7.38Å和7.46Å），相应地加入Al3+或Ca2+的活性物质的比容量也有较大的提高（加入相同浓度的Al3+和Ca2+模板剂后其活性物质的比容量分别比加入K+的提高了35.3%和19.5%。）。这说明选择不同的阳离子模板的种类可以调控δ-MnO2的层间距进而提高其比容量。.本项目的研究结果对于进一步发展先进的薄膜型超级电容及提高氧化锰基超级电容器电极材料的电化学性能有着科学的依据与支持。