自支撑碳基柔性电极的构筑、调控及其在储能器件中的应用基础

Aiming at the small area, poor structure stability, low enengy density of the current carbon-based flexible electrodes, this project proposes a large area carbon-based flexible electrode prepared by electrostatic spinning technology. By using several polymers mixing precursors, adjusting the contents in the precursor, different nonmetal element doped flexible electrodes with various kinds of carbons are obtained, and then their applications in energy storage devices are also investigated. The proposed research will focus on three parts: (a) the preparation and structure controlled of the flexible electrodes; (b) effects of microstructure/compositions of electrodes on the mechanical properties and electrochemical performance, especially for the long cycling stability; (c) the influence of elemental doping and compositions on the stability of electrode/electrolyte interface. Finally, large-area carbon-based flexible electrodes with high structural stability and excellent electrochemical performance are obtained. From the theoretical level, the proposed project will study on the influence laws of the compositions, structures, mechanical properties on the electrical conductivities and electrochemical properties of the flexible electrodes; elucidate the mechanisms underlying the nonmetal doped and carbon type affect the interfacial and electrochemical properties. From a technical point of view, the project will establish the preparation of high performance, repeated bending without flexible electrode attenuation structure failure and performance flexible electrodes. The research results will provide theory and technology basis for the preparations and applications of carbon-based flexible electrode which have important scientific significances and practical values.

针对目前碳基柔性电极面积小、结构稳定性差、能量密度低等问题，本项目提出采用静电纺丝技术制备大面积、结构稳定的碳基柔性电极，通过多种聚合物混合纺丝来丰富碳化产物的孔隙结构，通过混入高导电碳来优化导电性和柔韧性，通过调控前驱液的成分获得非金属元素的掺杂及高负载，并研究其在储能器件中的应用。研究内容包括柔性电极制备和结构调控，微观结构/组成对电极机械性能和电化学性能的影响，非金属掺杂和复合成分对电极界面稳定性的影响，最终获得大面积、结构稳定、高电化学性能的柔性电极。本项目将从理论层面上研究碳基柔性电极的组成、结构等对机械性能和电导率乃至电化学性能的影响规律，阐明非金属元素掺杂和碳类型影响其界面和电化学性能的内在机制。从技术层面上，研制出高性能的反复弯曲无结构失效和性能衰减的电极，建立完善的制备工艺。研究成果将为碳基柔性电极的制备和应用提供理论和技术基础，具有重要的科学意义和实用价值。

本项目针对目前碳基柔性电极面积小、结构稳定性差、能量密度低等问题，采用静电纺丝技术制备了系列大面积、结构稳定的碳基柔性电极，发展了柔性氮掺杂碳纳米纤维电极、氮硫共掺杂碳纳米纤维电极、SnO2/CNF复合电极、FeS@CNFs复合电极及SnS2/CNF复合电极，并探索了它们在锂/钠离子电池中的应用，考察了氮、硫掺杂及复合组分对碳纳米纤维基电极的电子电导、储能机制、电化学容量等的影响规律，最终实现电池的容量、循环稳定性、大电流充放电性能的大幅提升。此外，在高容量锂硫电池方面，发展了多孔氮掺杂碳纳米纤维与石墨烯的复合材料，通过高导电碳的混入和改变碳化条件来优化碳纳米纤维的电子电导，通过刚性模板SiO2微球的引入来调控碳纳米纤维的多孔结构，最终实现柔性电极膜片机械强度的提升，此外所获得的高孔容的碳纳米纤维可以实现S载量的提高，进而提升锂硫电池的能量密度。在此基础上，通过在多孔碳纳米纤维内进一步引入极性化学吸附TiO2颗粒来提升对多硫化物的吸附作用，抑制电池循环过程中多硫化物的穿梭效应，提升锂硫电池的循环稳定性。本项目从理论层面上研究了碳基柔性电极的组成、结构等对机械性能和电导率乃至电化学性能的影响规律，阐明了非金属元素掺杂和碳类型影响其界面和电化学性能的内在机制。技术层面上，研制出了高性能的反复弯曲无结构失效和性能衰减的电极，建立了完善的制备工艺。该研究成果为碳基柔性电极的制备和储能电池体系中的应用提供了理论和技术基础，具有重要的科学意义和实用价值。