基于多金属协同效应的类普鲁士蓝的设计合成及储钠性能研究

Prussian blue analogues (PBAs) with specific open framework structure provide abundant reaction sites and migration channels for the reversible insertion/extraction of Na-ions. While the attendance of Fe(CN)6 defects caused low capacity and poor cyclic performance, which limit the practicle applications of PBAs cathodes. According to these drawbacks, we plan to develop a multi-metal synergistic PBAs, and improve Na storage performance through the following four lines:.1. By in-stu infrared controlled synthesis, we produce high-quality PBAs products..2. According to the relationship between transition metal components and electrochemical performance, multi-metal PBAs cathodes with stable framework structure and double Na+ insertion reactions are designed and fabricated..3. In-stu characterizations and theory simulations were performed to analyze Na+ storage mechanisms, as synergistic effects among the transition metals, charge transfer mechanisms, and structural evolution in reaction process, furthermore to targeted synthesis of multi-metal PBAs..4. Na-ion full-batteries based on thus-prepared PBAs cathodes are fabricated and optimized..In our previous studies, nickel based PBAs cathode and hard carbon anode full-batteries were fabricated with a high energy density of 210 Wh/kg (calculated by the mass of cathode). They show stable cyclic performance without obvious capacity decay with a specific energy retention of 85% after 1000 cycles, and a well rate performance with capacity retention of 80% for 5C. The as-prepared battery basically meets the practical applications. Further, we plan to design and fabricate high-quality, high capacity and stable structured multi-metal PBAs to obtained high-performance Na-ion cells with specific energy as 100 Wh/kg.

类普鲁士蓝（PBAs）独特的开放式框架结构为钠离子的可逆脱嵌提供了丰富的嵌入位点和传输通道，而常规合成的PBAs循环稳定性差、比容量低限制其发展。本项目针对这两个瓶颈，设计、合成多金属协同作用的PBAs，从以下四个方面开展工作：1.原位红外监测技术，结合络合剂辅助合成法，降低PBAs产物缺陷度；2.由金属组分与性能的构效关系，构筑双电子转移、配位结构稳定的PBAs；3.原位表征结合计算模拟，研究多金属协同效应包括：电荷传输机制，反应中的结构演变，用于指导多金属PBAs组分设计；4.设计、组装高比能、长循环钠离子电池。申请人已研制的PBAs-HC（硬碳）全电池的能量密度达210Wh/kg（正极质量），循环1000圈能量保持率达85%，5C下容量保持率达80%。本项目通过研发高活性、结构稳定的PBAs正极材料，开发比能量约100Wh/kg，循环1000次能量保持率大于80%的单体钠离子电池。

本项目以钠离子电池正极材料类普鲁士蓝化合物为主要研究对象，以发展高性能钠离子二次电池为目标，围绕材料结构特征与电化学性能之间的关联开展工作。开发了原位红外监测手段用于类普鲁士蓝共沉淀合成和陈化阶段的实时监控方案；研究结晶性、晶格水对类普鲁士蓝性能的影响；探索了类普鲁士蓝过渡金属协同效应；完成工艺配方的初步探索，并初步尝试应用于单次＞20kg的生产。在本项目的资助下，研究成果在Nano Energy， EnSM， Chem. Comm.， ACS Appl. Mater. Interfaces等重要期刊发表，总计发表学术论文10余篇，申请国家专利7件。该项目为设计和合成适用于钠离子电池的高性能类普鲁士蓝正极材料提供可靠的理论基础和实验依据，对推动适用于大规模储能的新型储能电池的实用化发展具有重要的意义，所述类普鲁士蓝生产工艺获得产业界的认可，圆满完成项目预期目标。