氧化钼薄膜的制备和电化学性能调控
发布时间：2018-11-12 20:29
【摘要】：微型电化学电容器是一种可集成于芯片上的电化学储能器件，，是为电子器件供能的微能源系统的重要环节，目前处于快速发展阶段。它对电极材料的要求是在有限体积和面积内提供高电容量，可快速充放电，并且循环寿命长。氧化物是一类赝电容材料，比电容大，但通常不导电，倍率性能和循环稳定性差。本文通过研究氧化钼薄膜的制备和电化学性能，探索了通过成分、结构和形态来调控电化学性能的途径，考察了其在微型电化学电容器中应用的可能性。 采用磁控溅射技术对MoO3进行还原溅射的方法制备了导电的MoO2+x薄膜，这种薄膜具有晶态MoO2和非晶态MoOx（2x≤3）共存的微观结构，在Li2SO4电解液中表现出赝电容性质。通过对其独特的循环伏安曲线特征的研究，提出了该薄膜的电化学机制，认为赝电容主要来自H+和Li+在非晶态MoOx中的可逆嵌入脱出，而且H+具有更大的活性；同时，MoO2晶粒可催化其表面的结合水分解产生H原子可逆地储存于非晶态MoOx中，促进赝电容过程的进行。除此之外，MoO2晶粒的形成还起到构成导电通路和维持薄膜结构稳定的作用。测试表明，这种氧化钼薄膜的电化学性能优于相似厚度的双电层电容型微电极。以MoO2+x薄膜作为负极、电沉积MnO2薄膜作为正极组装了非对称赝电容型微电容器MoO2+x||Li2SO4||MnO2，获得了良好的性能，表明了这种氧化钼薄膜是一种性能优异的负极材料，有望在微型电化学电容器中实现可靠应用。 对电化学沉积的水合非晶态氧化钼薄膜进行还原气氛退火处理，研究了温度和退火时间对电化学性质的影响，选定了最优实验条件，制备了含有MoO2纳米晶和非晶态MoOx的薄膜，获得了良好的倍率性能、循环稳定性以及较高的比电容。由于电化学沉积灵活简便，可在不同形貌的集流体上进行，因此该方法可用于开发新型结构的微电极。采用电子束蒸发倾斜生长技术沉积了Ti纳米棒阵列作为三维集流体，继而用电沉积法包覆氧化钼赝电容活性层，实现了三维结构微电极的制备，获得了较高的面积比电容和优良的循环稳定性。再通过还原气氛退火处理，进一步提高了倍率性能，获得了较快的响应速度。由此，大表面积电极结构的设计进一步改善了氧化钼电极的性能，为其在微电容器中的应用奠定了基础。
[Abstract]:Micro electrochemical capacitor is a kind of electrochemical energy storage device which can be integrated on chip. It is an important part of the micro-energy system which can supply energy for electronic devices. It is currently in the rapid development stage. The electrode material is required to provide high capacity in a limited volume and area, rapid charge and discharge, and long cycle life. Oxide is a kind of pseudo-capacitive material with large specific capacitance, but it is usually not conductive, and its rate performance and cycle stability are poor. In this paper, the preparation and electrochemical properties of molybdenum oxide thin films were studied, and the ways to control the electrochemical properties by composition, structure and morphology were explored. The possibility of its application in micro electrochemical capacitors was investigated. Conductive MoO2 x thin films were prepared by reduction sputtering of MoO3 by magnetron sputtering technique. The films have the microstructure of crystal MoO2 and amorphous MoOx (2x 鈮
本文编号：2328134
[Abstract]:Micro electrochemical capacitor is a kind of electrochemical energy storage device which can be integrated on chip. It is an important part of the micro-energy system which can supply energy for electronic devices. It is currently in the rapid development stage. The electrode material is required to provide high capacity in a limited volume and area, rapid charge and discharge, and long cycle life. Oxide is a kind of pseudo-capacitive material with large specific capacitance, but it is usually not conductive, and its rate performance and cycle stability are poor. In this paper, the preparation and electrochemical properties of molybdenum oxide thin films were studied, and the ways to control the electrochemical properties by composition, structure and morphology were explored. The possibility of its application in micro electrochemical capacitors was investigated. Conductive MoO2 x thin films were prepared by reduction sputtering of MoO3 by magnetron sputtering technique. The films have the microstructure of crystal MoO2 and amorphous MoOx (2x 鈮
本文编号：2328134
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