全二维金属碳化物(MXene）基柔性可延展一体化互连电极阵列构筑与性能研究

Currently, the low energy density and lack of stretchability of planar micro-supercapacitors (MSCs) greatly restrict their application in the field of flexible and wearable energy storage devices.Therefore, we attempt to design and synthesis flexible and stretchable integrated electrode arrays based on two-dimensional (2D) metal carbides (MXene). 2D monolayer MXene with high conductivity and high specific volumetric capacitance are first employed to fabricate thin film electrodes, which can realize the fast transport of electrons and ions while achieveing storage of charge, resulting in the eletrode fully laden with active materials of high specific capacitance. The electrochemical and mechanical performances of the thin film eletrodes will be optimized through controlling the lateral size of 2D monolayer MXene, the interlayer space of the closely restacked MXene flakes and surface modification, realizing the fabrication of flexible thin film electrodes with high specific capacity. By combing the methods of laser cutting and finite element analysis, the integrated electrode arrays with island-bridge structure were constructed to be employed to achieve stretchable mechanics of the MSCs. The relationship between the mechanical characteristics and the structural parameters of the serpentine interconnect (bridge) will be studied. Meanwhile, the corresponding relationship on the elastic stretchability and stability of electrochemical performance of the integrated electrode arrays with island-bridge structure, and the geometric structure of the serpentine interconnect (bridge) will be clarified. It will provide a new insight on developing flexible and stretchable MSCs with high energy density if the proposed all-MXene-based flexible and stretchable integrated electrode arrays design is achieved successfully in experiment.

当前，平面微型超级电容器较低的能量密度和延展性的缺乏，制约了其在柔性可穿戴储能器件领域的应用。据此，本项目拟开展全二维金属碳化物（MXene）基柔性可延展一体化互连电极阵列的设计与制备。利用高电导率，高比电容的二维单层MXene构筑薄膜电极，在实现电子/离子快速输运的同时完成电荷的存储，达到高比电容材料全电极负载；通过调控MXene片层尺寸，表面结构和层间域，调节电极的电化学性能和机械性能，在满足柔性化需求的同时实现高比容量薄膜电极制备。同时结合激光切割技术和有限元分析，以一体化互连岛桥结构电极阵列的构建实现器件结构的可延展性；探索蛇形导线(桥)力学特征与结构参数的关系；揭示全MXene基一体化互连岛桥结构电极阵列的可延展率、电化学性能稳定性和蛇形导线(桥）几何结构的构效关系；提出的全MXene基一体化互连电极阵列设计如获实验成功，将为发展高能量密度可延展超容器件提供崭新的设计制备思路。

平面微型超级电容器较低的能量密度和延展性的缺乏，制约了其在柔性可穿戴储能器件领域的应用。据此，本课题研究以新型二维单层过渡金属碳化物(MXene)基材料进行高比电容电极设计，并探索采用激光切割技术，以高比容量MXene基柔性薄膜电极为基础，进行一体化可延展电极阵列的构建，进而实现兼具高能量密度和可延展超容器件的设计制备，取得了以下重要进展：.(1).提出一种层间电子/离子双传输通道电极设计策略：基于一维导电细菌纤维素@聚吡咯在二维单层MXene片层间的均匀插层，同步构筑了层间电子/离子双传输通道，有效缓解了二维单层MXene自组装薄膜由片层密堆积引起的层间离子传输受阻以及由插层物引起的层间电子传输受阻问题，实现了复合电极薄膜储荷性能的有效提升，并通过与碳纳米管@二氧化锰电池型薄膜电极配对，所构筑的微型锌离子超级电容器实现了高达145.4 μwh cm-2的面能量密度，接近微型电池能量密度水平。.(2).开发出一种新型器件架构-微型氧化还原电容器。通过在MXene自组装薄膜电极层间原位耦合具有氧化还原活性银纳米线为阴极与纯锌阳极配对，并采用聚丙烯酰胺/氯化锌+氯化铵固态水凝胶电解质, 实现了在微型氧化还原电容器中整合了基于MXene的离子插层赝电容和银/氯化银之间固-固相转换氧化还原反应的双重储荷机制，最终达到了在不降低器件面积功率密度(0.17 mW cm-2)的前提下，实现了器件面能量密度的有效提升(227 μWh cm-2)。并通过原位拉曼光谱和X射线衍射谱，阐明了其储荷机制。.(3).采用中国传统剪纸工艺策略和高精度激光切割技术，以高面电容密度MXene 基复合电极为基础，实现了一体化可延展电极阵列的构建，获得了具有111.5 mF cm-2面电容密度及100%拉伸率的可拉伸超容阵列。.(4).基于具有几何可拉伸性的岛桥电极结构和本征可拉伸性的液态金属电路设计，通过集成高能量密度MXene基超容器件，实现了兼具更高延展性(400%)和输出能量 (128.4 μWh)的MXene基微型超容阵列的制备。并通过有限元分析理论模拟计算结合原位三维全场应变测量分析系统，揭示了其拉伸性能与结构参数之间的关系。