兼具高容量与高功率的“微区溶解/吸附”型转换电极反应体系

基于钠离子存储反应的电池/电容混合体系兼具能量与功率密度、资源与成本优势，是新一代电化学储能技术发展的重要方向。然而，现阶段的钠离子混合电容器大多是基于电池嵌入反应与电容双电层反应构建的，受限于电池型电极与电容型电极的电化学反应不协调，很难真正实现能量密度与功率密度的优势互补。为了解决这个问题，本项目提出了构建“微区溶解/吸附”型转换反应电极的新思路，利用多电子转换反应的高容量，“微区溶解/吸附”机理的快速动力学，实现高能量密度的混合电容储能体系。在前期研究基础上，拟选择典型的过渡金属硫化物为主要目标体系，系统深入地研究材料组成结构、电解液性质对于“微区溶解/吸附”机理、转化反应动力学的影响规律，探索适合“微区溶解/吸附”反应机制的电极结构与电化学环境，阐明这类电极反应的电化学特征和应用性质，为发展新一代高性能电池/电容混合储能体系提供理论基础和技术支撑。

Sodium-based battery/supercapacitor hybrid energy storage systems are attractive candidates for the next generation electrochemical energy storage technologies, due to the advantages of high energy/power densities, resource abundance and low cost. At present, sodium ion hybrid batteries (SIHC) are mostly constructed based on the insertion/extraction reactions combined with electrochemical double-layer reactions. It is difficult to effectively combine the advantages of high energy densities and power densities of batteries and supercapacitors, due to the incongruity of the battery-type and capacitive-type reactions. To solve these problems, this project proposes a novel strategy to develop energy storage systems based on the “microdomain dissolution/adsorption” conversion reaction mechanisms. Benefiting from the multi-electron conversion reactions and fast kinetics of “microdomain dissolution/adsorption” mechanisms, both high energy densities and power densities can be achieved for the novel SIHC. In order to realize this concept, transition-metal chalcogenides (TMCs) are selected as the typical electrodes for “microdomain dissolution/adsorption” conversion reactions. The relationships between the chemical structure, reaction mechanisms and redox kinetics are investigated in-depth and systematically to reveal the optimized chemical structure and electrochemical environment for the “microdomain dissolution/adsorption” conversion reactions. The practical applications of the “microdomain dissolution/adsorption” conversion reactions are further evaluated in the novel hybrid energy storage systems. Those explorations may provide theoretical guidance and technical supports for the regular design and applications of next generation battery/capacitor hybrid systems with high performances.