富钾普鲁士蓝类配合物及其复合正极材料的可控制备和其储钾及机理研究

Potassium-ion Batteries (PIBs) is concerned grandly because the advantages of abundant resources, low cost and high safety performance, and comprehensive electrochemical performance is similar to that of Lithium-ion Batteries (LIBs)，which is been regarded as the next generation storage technology. The development of high-performance cathode material is the precondition and key of the large-scale commercialization of PIBs. Prussian Blue coordination compound is one of the ideal cathode materials for PIBs, which has the advantages of high theoretical capacity and stable voltage platform, at present the Prussian Blue is confronted with the problem of high lattice defect and poor cyclic performance, which can’t meet the commercial demand. The application project uses a simple and environmentally friendly method to realize the crystal lattice defect, potassium content and molecular structure of potassium-rich Prussian blue materials by using the weak binding force of K-ions and water molecules. The development of a series of high charging capacity, high reversible capacity, high voltage platform and excellent cycling performance of the serial sodium ion battery cathode materials. Combining the first principle VASP calculation with In-situ XRD and Ex-situ TEM to research the mechanism of sodium storage in Prussian blue and find the regularity of the universality of sodium storage the for potassium-rich Prussian blue. Combine with the advantages of graphene rolls and graphene quantum dots, we synthesize potassium-rich Prussian blue composites to improve the cycle and rate performance of Prussian blue at finally, which was the basis research for the commercialization of PIBs.

钾离子电池综合电化学性能与锂离子电池相近，具有资源丰富、成本低廉、安全性能高等优点而备受关注，是锂离子电池候选储能技术。开发高性能的正极材料是钾离子电池大规模商业化使用的前提与关键。普鲁士蓝类配位聚合物是钾离子电池理想正极材料之一，具有理论容量高、电压平台稳定的优点，目前普鲁士蓝面临晶格缺陷高、循环性能差的问题，还不能满足商业化需求。本申请项目利用钾离子与水分子结合力弱的特性，采用简单而环保的方法来实现富钾普鲁士蓝类材料晶格缺陷、钾含量、以及分子结构的精准设计；开发首次充电容量高、可逆容量高以及电压平台高的系列钾离子电池正极材料；结合第一性原理VASP计算与原位XRD、非原位TEM等测试方法深入研究普鲁士蓝的储钾机理，总结富钾普鲁士蓝储钾普适性规律；结合石墨烯卷、石墨烯量子点优势，制备富钾普鲁士蓝复合材料来改善富钾普鲁士蓝循环性能、倍率性能，为钾离子电池的商业化积累研究基础。

以比亚迪为代表的电动汽车的大规模推入市场，使得锂离子电池的使用量愈来愈大，电池级碳酸锂的消耗量越累越多，锂资源的匮乏问题愈发突出，2022年电池级碳酸锂的价格一度超过52万元/吨，因此科学家们一直在积极寻找新的二次电池技术来弥补锂资源不足的问题。钾元素与锂在元素周期表中同主族，具有类似的物理化学性质，钾离子电池(Potassium-ion Batteries, SIBs)在结构、组件、储能机制上和锂离子电池相似，可以借鉴锂离子电池的发展经验。目前宁德时代推出了商用钠离子电池，并着手开发商用钾离子电池。本项目选用普鲁士蓝作为钾离子电池正极材料，设计合成具有低缺陷、富钾普鲁士蓝；探索不同金属元素对电池电压，容量的贡献机金属元素间协同作用与电化学性能的关系，从微观层面上揭示普鲁士蓝储能机理、影响机制及与电解液之间的匹配规律，本项目的实施将对电极材料的可控设计以及钾离子电池的发展提供有用的理论及实验指导依据。