基于MnO2-碳纳米管和Fe2O3-碳纳米管同轴纤维状非对称超级电容器的有效构筑及其损伤失效行为

One-dimensional fiber-shaped solid-state supercapacitors with excellent flexibility, safety and weavability have a great application prospect in the field of wearable electronics. However, there are two main disadvantages in such devices: the low energy density and the poor structural stability. In this project, the design and construction of the coaxial fiber asymmetric supercapacitors is proposed to improve the energy density and structural stability. Through the new design of inner current collector, gel electrolyte, outer current collector and encapsulation film to optimize the mechanical properties of each functional layer, the structural stability of the device is improved. The composite materials of MnO2-carbon nanotube (CNT) and Fe2O3-CNT are used as active materials in positive and negative electrodes, respectively. The structure-activity relationship between the preparation process, microstructure and electrochemical performance of each composite material is studied, respectively. Therefore, the controllable preparation and the performance control of each composite material are realized. The matching law of positive and negative electrodes is revealed and the amount of positive and negative active materials is adjusted to balance charges of the positive and negative electrodes. Then, the energy density of coaxial fiber-shaped asymmetric supercapacitors is improved effectively. A joint detection platform of the mechanical performance-electrochemical performance, as well as damage-free X-ray computed tomography technology, is used to study the damage and failure behavior under force. The correlation mechanism among force, internal structure and energy storage performance is clarified. The research results can provide a theoretical basis and a technical support for the development of high-efficiency flexible/ weavable energy storage devices for smart fabrics.

一维纤维状全固态超级电容器具有优异的柔性、安全性和可编织性，在可穿戴电子领域具有广泛的应用前景。本项目针对此类器件能量密度低和结构稳定性欠佳等问题，构筑基于复合材料的同轴纤维状非对称超级电容器并开展性能研究。设计具有新型结构的内电极基体、凝胶电解质、外集流体和封装膜等功能层，优化其机械性能，提升器件结构稳定性；选用MnO2-碳纳米管和Fe2O3-碳纳米管复合材料为正、负极活性材料，研究各复合材料制备工艺、微观结构和储能性能的构效关系，实现其可控制备和性能调控；揭示正、负极匹配规律，控制正、负极活性材料用量以平衡两极电量，实现同轴纤维状非对称超级电容器能量密度的有效提升；搭建机械性能-电化学性能联合检测平台，借助无损伤X射线断层扫描技术，研究机械受力时器件损伤失效行为，阐明机械受力-内部结构-储能特性之间的关联机制。研究结果能为智能织物用高效柔性可编织储能器件的开发提供理论基础和技术支撑。

一维纤维状全固态超级电容器具有优异的柔性、安全性和可编织性，在可穿戴电子领域具有广泛的应用前景。本项目针对此类器件能量密度低和结构稳定性欠佳等问题展开研究，构筑了基于棉纤维/不锈钢纤维混纺线的纤维状非对称超级电容器，调控了正负极配比，优化了非对称器件的工作电压。搭建了电化学-机械性能检测平台，研究了外力作用对器件电化学性能的影响；搭建了纤维电极制造装备，实现了器件长度从厘米级到米级的提升，并试制了储能织物，考察了器件在织物中的储能特性，表明所制备的米级长度的器件具有应用于智能织物的巨大潜力。项目执行期间，发表学术论文 4篇，申请和授权发明专利 6项，培养研究生4 人，本科生 6人。研究目标已全部完成。项目主要有以下研究进展：研究了不同纤维配比对混纺线集流体的机械性能和导电性能的影响，确定了不锈钢纤维体积占比65%的混纺线为基底材料。探究了不同活性材料质量配比对纤维状电极电化学性能的影响，优化了纤维状电极的电化学性能；搭建了浸涂提拉平台和三轴自动浸涂式聚合装置，完成了米级长度纤维状正、负极的制备。基于电量平衡原理，调控正、负极电量匹配，构筑了全固态纤维状非对称超级电容器，显著地拓宽了器件的工作电压，将电压窗口由0.8V提升至1.7 V，有效提升了器件的能量密度，且器件在不同弯折角度和多次弯折后仍表现出较好的电容保持率，展现出良好的柔性。搭建了电化学-机械性能检测平台，研究了外力作用对储能器件电化学性能的影响，发现该器件在一定外力拉伸的情况下，仍能保持较好的储能特性；实现了全固态纤维状非对称超级电容器长度规模从厘米级到米级的提升，将纤维状器件织入织物后，器件仍能保持良好储能特性，充电后可为外部负载（LED和计时器）供能，表明米级长度的器件在智能织物中应用的可能，该研究可为可编织纤维状超级电容器的研发提供理论和技术支撑，具备重要的科学意义和应用价值。