基于准二维过渡金属硫族化合物材料的电子态性质调控及其储能机制研究

Supercapacitor is one novel, highly efficient and clean energy storage device, but its present energy density is relatively low. How to rational design and explore the electrode materials with high specific capacitance to improve the energy density is the key issue to be urgently solved. The quasi-two-dimensional transition metal dichalcogenides (TMDs) have been the ideal electrode materials due to their large surface area and excellent physical and chemical properties. The impact of the quantum capacitance in low-dimensional materials on the total specific capacitance is large. However, the correlation between the microscopic atomic structures, the electron structures of TMDs and their quantum capacitance is not clear. Thus, for different types of structures, the dependence of the quantum capacitance in quasi-two-dimensional TMDs on the strength of the interaction between electrons and the carrier concentration will be explored using first principles calculations method, theoretically analytical formulas and numerical simulation approaches. The synergetic manipulations of the intrinsic defects, the doping impurities and the surface functionalizations in 1-3 layered TMDs on their electronic structures and the quantum capacitance will be investigated and unveiled. The influence of the ion adsorption on and insertion on the specific capacitance will be calculated. The schemes to improve the specific capacitance and realize the best charge storage capacity in TMDs will be proposed...These investigations of this project will provide the fundamental basis for the electronic states manipulation, the understanding of the energy storage mechanism and the further applications in ultrathin and flexible electrode materials with quasi-two-dimensional TMDs. Therefore, they are significant both in theoretical researches and in practical applications.

超级电容器作为一种新型高效清洁的储能装置，其能量密度较低，如何设计开发具有高比电容的电极材料以提高其能量密度是目前亟待解决的关键问题。准二维过渡金属硫族化合物(TMDs)因具有大比表面积和优异的物理化学性能而成为理想的电极材料。鉴于低维材料的量子电容对总电容影响大，而TMDs的微观原子结构、电子结构与量子电容的关系尚不清楚。本项目拟采用第一性原理计算与理论解析和数值模拟相结合的方法，针对不同结构的TMDs，研究电子间相互作用和载流子浓度对量子电容的影响，揭示缺陷、杂质及表面修饰对1-3层TMDs材料的电子态性质和量子电容的协同调控机制；同时通过探索离子吸附和插入对电子结构和比电容的影响，提出提高比电容、实现最佳电荷存储的有效方案。.本项目的研究对准二维TMDs电子态性质的调控和储能机制的理解以及在超级电容器超薄柔性电极材料上的应用奠定基础，因此无论在理论研究还是实际应用上都具有重要意义。

为提高以超级电容器为代表的储能器件的能量密度，阐明低维电极材料的量子电容、赝电容与其晶格结构和电子结构关系的微观机制，在此基础上设计、开发、调控具有高比电容性能的电极材料，是目前亟待解决的关键问题之一。本项目采用理论解析、数值计算与第一性原理计算相结合的方法，结合二维过渡金属硫族化合物（TMDs）和石墨烯等材料的结构特点，研究了二维单层、双层及异质结体系的电子结构与量子电容性质，阐明了晶格结构、载流子浓度、电子间相互作用强度、缺陷和自旋极化对体系的电子态性质和量子电容调控的物理机理；发展了利用表面修饰结合离子掺杂调控体系的载流子浓度进而提升量子电容的有效方案；研究了TMDs电极材料表面的离子吸附、插入的微观过程及赝电容机理，探索提出了通过引入缺陷提升赝电容的方案；在此基础上，拓展了低维电极材料体系，通过高通量计算筛选并研究了367种一维原子线体系新奇的电子态和磁基态性质；同时探索研究了与低维电极材料匹配良好的二维原子孔材料MX3用作固态电解质材料的电子结构和离子传输性质，揭示了其具有超快离子传输性能的微观机制，提出并验证了其作为固态储能器件中金属电极保护层的可行性。本项目的研究，为TMDs及其它低维材料的结构-电子态-量子电容和赝电容性质机理的理解和性能调控提供了理论依据，也为高效储能器件的设计开发和实际应用提供了理论支撑和具体的低维材料体系。在本项目的支持下，项目团队已正式发表SCI检索学术论文13篇，包括Nano Lett., Appl. Phys. Lett., Appl. Surf. Sci., Nanoscale, J. Phys. Chem. C, Mater. Chem. Front., ACS Appl. Energy Mater., J. Appl. Phys., J. Phys.: Condens. Matter等，其中2篇论文被选为“编辑推荐”文章，1篇论文被选为“Inside Front Cover”文章，获授权国家发明专利2项，获软件著作权登记2项。