普鲁士蓝及其复合正极材料的储钠性能及机理研究

项目名称： 普鲁士蓝及其复合正极材料的储钠性能及机理研究

项目编号： No.21503071

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 分析化学

项目作者： 刘阳

作者单位： 河南师范大学

项目金额： 21万元

中文摘要： 普鲁士蓝类材料作为钠离子电池正极，价格低廉、理论比容量高，具有良好的应用前景。近期，我们在NaxFeFe(CN)6的合成和储钠性能研究中发现，材料的电化学性能与Na+占位有关，富钠态材料的储钠容量及首次库伦效率更佳。然而，普鲁士蓝类材料存在首次库伦效率低和大电流密度下循环稳定性较差等问题，需进一步改善其储钠性能。本项目提出开展普鲁士蓝及其复合正极材料的储钠性能及机理研究。通过调控合成条件来控制材料的粒径、形貌和微纳结构。结合理论计算和电化学测试，阐明材料微纳结构、电极表界面性质、钠离子配位环境、空位、结晶水与储钠容量及库伦效率的构效关系，寻求提高储钠容量的最佳方案。进一步采用导电高分子修饰，研究复合材料充放电过程中结构变化及表界面问题，揭示储钠机制和动力学性质，建立具有代表性的普鲁士蓝复合正极材料，提出切实可行的改性策略。为普鲁士蓝在钠离子电池中实际应用提供理论依据与借鉴思路。

中文关键词： 钠离子电池；普鲁士蓝；复合正极材料；电化学性能；储钠机理

英文摘要： Prussian blue analogues (PBs) as cathode materials for sodium ion batteries, with low cost and high theoretical capacity, show promising application. Recently, our investigations on the synthesis and sodium storage properties of NaxFeFe(CN)6 demonstrate that the electrochemical performance is related to intercalation sites of Na+ ions in the structure, Na-rich products show better sodium storage capacity and first Coulombic efficiency. However, the sodium storage performance of PBs still need to be improved, due to its low Coulombic efficiency and poor cyclic stability at high current density. This project proposes investigation on sodium storage performance and mechanism of Prussian blue and its composite cathodes. The particle size, morphology and micro/nano structure of the product are controlled via adjusting the synthesis condition. We will elaborate the effect and structure activity relationship of micro/nano structure, surface and interface property, coordination environment of Na+ ions, vacancy and crystallization water on the sodium storage capacity and Coulombic efficiency, combined theoretical calculation and electrochemical testing, pursue the best strategy to improve the sodium storage capacity. The electrochemical performance can be enhanced via the modification of conducting polymers. This research will investigate the evolution of structure, surface and interface during charge/discharge process, reveal the sodium storage mechanism and kinetic properties, establish representative cathode composite based on PBs, propose the feasible modification strategy. These results will provide the theoretical basis and new ideas for the practical application of PBs in sodium ion batteries.

英文关键词： Sodium ion batteries;Prussian blue;Composite cathodes;Electrochemical performance;Sodium storage mechanism