基于二维过渡金属硫化物柱撑框架材料的构筑及其电化学能源存储

Two-dimensional (2D) transition metal dichalcogenides (TMDs) are promising electrode materials for high performance energy conversion and storage devices (such as lithium ion batteries and supercapcacitors) due to their unique physical, chemical, and electrochemical properties. However, most of the TMDs show very limited conductivity between two adjacent sheets as well as high tendency for reaggregation and stack together. This inevitable reaggregation and stacking significantly decreases the electrochemically active surface area, thus resulting in a deteriorated capacitance performance. Moreover, TMDs-based electrode materials also show remarkable volume change during charge/discharge processes, thus leading to significant capacity loss as well as poor rate capability and cycling stability. To circumvent these obstacles, in this project, we propose to direct connecting the basal plane of adjacent TMD nanosheets by covalent bonding with functional conjugated molecule pillars to yield TMDs-based frameworks. The TMD nanosheet gap size, microstructure, specific surface area, and pore size distribution of TMDs-based frameworks can be tailored at molecular scale by turning the functional conjugated molecule pillars. Moreover, the formation of TMDs-based frameworks can improve the electrical conductivity of TMDs, especially in c-direction, overcome the aggregation and restacking of TMDs nanosheets, accommodate the volume expansion upon charge/discharge processes, and provide the largest interface contact for the electron/ion transfer, thus resulting significant improvement of capacity as well as excellent rate capability and cycling stability.

二维过渡金属硫化物得益于其独特的物化性质和优异的电化学性能等，有望作为高性能电极材料应用于能源转换与存储器件（如锂离子电池和超级电容器等）。然而，大部分过渡金属硫化物导电性能相对较低，易发生不可逆的聚集和堆叠，严重降低其电化学活性面积和电容性能。在循环过程中存在较大的体积变化，不可逆容量损失大，循环稳定性及倍率性能差，大大限制了二维过渡金属硫化物的实际应用。本项目拟在纳米尺度上优化设计二维过渡金属硫化物材料的结构，采用功能性共轭小分子柱将相邻的金属硫化物纳米片以共价键的形式紧密结合形成柱撑多孔框架材料，克服片层之间易堆叠的问题。实现在纳米尺度上对金属硫化物纳米片层间距的可控，并实现在纳米尺度上对其多孔结构（孔径尺寸，孔径分布等）和比表面积等进行有效、精确调控，优化电极/电解液固液界面实现快速的电子通路和优异的速率性能，缓解循环过程中的体积变化，有效提高电容性能、倍率性能及循环稳定性。

开发了一种通用的一步原位合成策略制备金属硫化物/石墨烯电极用于高性能超级电容器。发展了铝掺杂结合镍纳米管阵列策略大幅提高超级电容器倍率性能。提出共轭微孔聚合物共价修饰MXene策略，有效提高导电性和稳定性，实现高比容量和高倍率性能。首次通过电化学沉积法制备镍钴磷酸盐超薄纳米片实现高容量与高倍率电化学能量存储。提出精确调控正负电极的匹配性策略大幅提高水系非对称超级电容器电压及能量密度。发展了一种异质结电极材料策略，实现宽电压水系不对称超级电容器。开发了碳纤维/石墨烯负载空心Co3O4超粒子结构应用于超级电容器性能提高。发展了一维-二维多级结构一体化电极策略有效提升超级电容器性能及其稳定性。该项目已在J. Am. Chem. Soc.；ACS Nano; ACS Energy Lett.; Nano Energy; Adv. Sci.; Sci. China Mater.等国际权威刊物上相继发表论文19篇，其中影响因子大于10的论文11篇。被Chem. Rev., Chem. Soc. Rev., Nat. Commun., J. Am. Chem. Soc., Angew. Chem. Int. Ed., Adv. Mater.等国际知名期刊引用和详细点评。期中J. Am. Chem. Soc., 2020，ACS Nano 2018, ACS Energy Lett. 2018三篇论文入选ESI高被引论文；J. Am. Chem. Soc. 2020和Small 2020两篇文章被选为封面文章。在超级电容器电极材料、电解液材料、器件结构等方面申请发明专利10余项，获授权发明专利2项；出版教材一部，撰写英文书籍一章；作为主要完成人获教育部自然科学奖二等奖1项，获省级教学成果奖二等奖（排名第三）。