非P基硫系和氟系钠固态电解质及其界面改性研究

In view of the potential applications of large-scale transportation or stationary energy storage, it is highly required to investigate low-cost, highly safe solid state battery technologies and their solid electrolyte materials. In this project, we intend to explore air-stable, phosphorus-free Na solid electrolytes based on sulfides and fluorides, and their interface modification routes, and then to construct high-performance solid state batteries based on Na metal anodes by integrating these novel electrolytes. The solid state architecture is expected to overcome some adverse phenomena usually existing in battery systems based on nonaqueous Na-salt electrolytes, such as unstable solid electrolyte interface (SEI) between Na anode and nonaqueous electrolyte. . We intend to develop novel air-stable sulfide solid electrolytes mainly based on Sn or Sb skeleton elements. The means including cation/anion doping, non-stoichiometric design and structural disordering will be adopted to enable high Na-ion conductivity, wide electrochemical window and stable plating/stripping of Na anode for these solid electrolytes. . We intend to explore novel phosphorus-free fluoride solid electrolytes and their structure prototypes with potentially high Na-ion conductivity by open framework strategy. Al-based garnet phase, antiperovskite phase and their derivative mineral phases characterized by interconnected 3D fast-ion channels will be developed in this project. . We intend to improve the grain boundaries of solid electrolyte and the interfaces between electrode and solid electrolyte by inserting polymer matrix (or interlayer) with desired functional groups, or by decorating ionic liquid wetting layer. By utilizing the feasibility of soft chemical synthesis for sulfide or fluoride solid electrolytes, we intend to achieve the coating of electroactive grains of cathode materials by nanostructured solid electrolyte components, and to optimize the mixed conductive network at cathode side, which is crucial for the highly reversible cycling of solid state Na-based batteries .

针对大规模移动储能和工业储能的重大需求，需迫切研究低成本、高安全的固态电池技术及其固态电解质材料，本项目拟探索空气稳定的非P基硫系和氟系钠固态电解质及其界面改性方法，并基于此构建高性能的钠基固态电池，以克服有机电解液体系中负极-电解质界面不稳定的缺点。开发基于Sn、Sb等骨架元素的新型硫系固态电解质，通过阴/阳离子掺杂、非计量比设计、无序化等手段，实现其高离子导电率、宽电化学稳定窗口和对于负极钠金属的稳定沉积/剥离。采用开框架策略来发掘具有潜在高离子导电率的非P基氟系结构原型，开发具有内部连通三维离子通道的Al基石榴石相、反钙钛矿相及其衍生矿物相的固态电解质。利用功能基团富集的聚合物基质、离子液体润湿层改善固态电解质的颗粒边界、电极-电解质界面；利用硫/氟系电解质的软化学法合成特色，实现固态电解质纳米结构组分对正极活性颗粒的包覆，优化正极端混合导电网络，以保证固态钠基电池的可逆高性能循环。

大规模电网静态储能和电动汽车移动储能对电池的能量密度、安全性和成本提出了更高的要求，本项目针对新型固态电解质设计及其界面构筑展开研究，着重围绕用于锂/钠基电池的氟系和氟化固态电解质材料的结构合成设计、稳定碱金属负极的聚合、氟化、离子液体浸润夹层界面构筑、动力学改善的氟化物和硫化物正极体系开发等方向取得了系列进展。（1）提出氟化反钙钛矿型和氟化冰晶石型的氟系固态电解质结构原型，实现了氟系固体电解质的离子电导率的最高记录，成功驱动了对应钠/锂金属电池的可逆循环；纳米结构的富锂氟化物作为高离子导电率的固态电解质界面组分，实现了对锂金属负极枝晶生长的有效抑制。（2）提出锂金属电池负极的非消耗型氟化流体界面调控、液态聚二甲基硅氧烷的界面原位催化嫁接、协同作用的离子“壳-核”型复合物添加剂设计等策略和概念，实现了亲锂聚乙烯醇和丝胶蛋白保形涂层对沉积锂的空间约束效应，使其空气稳定性显著提升，极大改进了高载量锂金属电池和高倍率锂硫电池的循环稳定性。（3）提出“固液氟通道”激活高能量密度的锂氟转换电池的创新思路；提出氟基催化的概念，实现了双金属（Fe-Cu）和尖晶石氧化物纳米晶域对LiF的高能效催化裂解；提出氟硫联动策略，设计出基于超薄氟化碳包覆和紧致颗粒堆叠粘合的FeS2正极材料，实现了高倍率、长循环、高比能的锂/钠金属基硫化物电池。