核壳NixCo3-xS4@C微纳结构设计、调控及赝电容储荷机制研究

With the intrinsic charge-storage advantages and existing key issues of cost-effective NixCo3-xS4 material for supercapacitor application in mind, we herein proposed an in situ self-sacrifical template/ion exchange/carbon coating strategy to construct core-shell NixCo3-xS4@C micro-/nanostrucutres with good electronic conductivity, large electroacitve surface area, hierarchical porosity and stable sur-/interfaces. Appealling electrochemical capacitance, including high power density, high mass/volume specific energy density and long cycling life, was eagerly expected via the fine design and rational regulation of the three aspects including the electrode composition, micro-structure and electrolyte components. The inherent formation mechanisms of the 3D hierarchical porous core-shell architecture were clearly revealed. General strategies to optimize the electrolyte components, new insights into the sur-/interfacial charge transfer between the pseudocapacitive NixCo3-xS4@C electrode and electrolyte, and new charge-storage mechanism were reasonablly delivered. Furthermore, extensive investigations were systematically performed into the immanent relationship between the adjustion of energy storage and syngery effect from the reversible redox couples in electrolytes and the specific composition, microstrucutres of the core-shell NixCo3-xS4@C hierarchical micro-/nanostructures. The underlying relationship and interaction theory between the electrode composition, microstrucutre, electrolyte components and electrochemical capacitance were developed and elegantly established. Finally, New insights and fundamental guidance would be provided accordingly for design, fabrication and practical applications of low-cost yet high-performance materials for supercapacitors.

基于低成本NixCo3-xS4在超级电容器应用中的储荷优势及所存在关键问题，本项目提出原位自牺牲模板-离子交换-碳包覆策略高效可控构筑具有高电子电导、高电活性表面、多级孔道和表界面稳定的核壳NixCo3-xS4@C微纳结构电极。通过对微纳结构组分、电极微结构和电解液组分三方面的设计与调控来实现核壳NixCo3-xS4@C微纳结构电极高比功率、高比电容和长循环寿命。阐释三维多孔核壳微纳结构形成机制，明确优化高电化学可逆氧化还原电偶的共性策略，阐明NixCo3-xS4@C电极/电解液表界面传荷新过程及储能新机制。考察核壳NixCo3-xS4@C电极组分、微结构和氧化还原电偶耦合作用与其电化学储荷特性之间本质关联性，提出调控策略，发展并建立电极组分、微结构、电解液组分-超电容特性之间构效关系及作用理论，为低成本高性能超级电容器电极材料及储能体系的设计、构筑及应用开发提供新的思路和科学依据。

基于低成本NixCo3-xS4在超级电容器应用中的储荷优势及所存在关键问题，本项目采用原位自牺牲模板‒离子交换‒碳包覆策略高效可控构筑了具有高电子电导、高电活性表面、多级孔道和表界面稳定的核壳NixCo3-xS4@C微纳结构电极。在调控核壳NixCo3-xS4@C微纳结构组分、微结构之余，在电解液中加入与之相适配的高可逆性氧化还原电偶来有效调控NixCo2-xS4@C电极/电解质表界面特性，进一步优化了其电化学传质和传荷过程。基于电化学测试、原位及非原位测试分析技术表征和理论模拟计算，揭示了前驱物与目标产物之间结构拓扑转变及三维多孔微纳结构形成机制，阐释了电化学诱导相变储电新机制，获知了优化电解液组分的共性策略，从微观层面系统探究了NixCo3-xS4@C微纳结构组分、电子结构、比表面积、三维多级孔道等微结构和电解液中高电化学可逆氧化还原电偶之间耦合作用与其电化学储能调控的内在关联，发展并建立了电极组分、微结构、电解液组分‒超电容性能之间构效关系及相关作用理论。通过电极组分设计、微结构调控、电解质组分优化及理论模拟计算，解决了其中理论和设计等问题，实现了核壳NixCo3-xS4@C微纳结构电极高比功率、高质量/体积比容量和长循环寿命。为制备低成本高性能超级电容器电极材料及储能体系提供器件原型、理论指导、技术支持、新的思路和科学依据。