基于水电解质溶液中离子嵌入反应的储能体系研究

Aqueous energy strorage and conversion systems, for example aqueous Li-ion and Na-ion batteries may solve the safety problem associated with lithium-ion batteries that use highly toxic and flammable organic solvents, and the poor cycling life associated with commercialized aqueous rechargeable batteries such as lead-acid and nickel-metal hydride systems. It providecs most promising potential for stationary power sources that store energy from sustainable sources, such as wind and solar power since it has low cost, high safety and long cycling life. However, it must solve many issues before going to pratical applications. . The aim of the present project is to study extensively some fundamental scientific issues of the aqueous lithium-ion or sodium-ion batteries. The energy storage mechanism in the intercalated compounds with different composition and crystal structure will be first studied. In particular, the electrode reaction mechanism in the aqueous elelctrolyte will be investigated, including the competive intercalation between Li/Na ion and pronton, the kinicts process of hygologen and oxygen evolution. Also the electrode/electrolyte interface reaction and the stability of the electrode material surface will be studied in order to clarify the capacity fading mechanism in aqueous electrolyte. Further more, the formation condition and mechnism of Solid Electrolyte Interphase (SEI) layer will be explored to improve the cycling stability of the electrode materials. By employing the nanotechnology and computational simulation, various electrode materials with a high specific capacity and high stability will be synthesized, and the new advanced new electrochemical system will be tested. As a final goal, the present project will provide some theoretical foundations and technical guidance to research and develop the advanced aqueous energy strorage and conversion systems (for example, Li-ion and Na-ion batteries) with a high power density, high safety and long cycling life.

基于嵌入反应的水系储能体可望解决现有有机系锂离子电池的安全性问题，也解决现有水系铅酸、镍氢电池循环寿命差的问题，具有低成本、高安全性及长寿命等特点，已经成为未来大型储能电池的首选器件之一，然而在实际应用中仍面临着诸多挑战。本项目将全面、系统、深入地研究基于水电解质溶液中离子嵌入反应的水系锂（钠）离子电池的前沿基础科学问题。研究不同组成和结构电极材料的储能机理，重点研究水系电极材料电极反应的机理，包括离子与质子的竞争嵌入反应、析氢和析氧等，研究电极材料/电解质溶液的界面反应及电极材料表面稳定性问题，阐明嵌入化合物在水溶液电解质中容量衰减机理,探讨水系电解液中电极表面形成有效固体电解质界面膜的条件及其生长机理。拟应用理论计算模拟及纳米技术，合成制备具有高比容量和结构稳定的新型电极材料，构筑新型水系锂（钠）离子电池。为设计高功率、高安全性和长寿命的新型电化学储能体系奠定理论基础并并提供技术指导。

本项目的总体目标是研究基于水电解质溶液中离子嵌入反应水系电池的前沿基础科学问题和应用技术。研究了几种锂、钠和锌离子嵌入化合物在水电解质溶液中的电化学行为和储能机理，研究表明电极材料的溶解、质子的竞争嵌入和析氢引起的pH值的改变是导致容量的衰减的重要原因，材料的碳包覆和提高电解质溶液的浓度可提高其稳定性；发现聚酰亚胺负极具有自消氧行为，解决了密封水系电池因过充可能析氧导致容量衰减的问题；研究表明具有共轭机构和碳氧双键的有机物和聚合物通过烯醇化反应可逆储存多种金属离子，并且具有很快电化学反应动力学过程，发展了几种新型高功率、长寿命的水系锂、钠和镁离子电池。研究了水系电池的电极和电池的组装工艺，实现了水系电池的产业化应用。此外，把水电解质溶液中嵌入反应电极作为氧化还原反应的中介电极，发展了电解水和氯碱的分步电解技术。上述研究结果为设计高功率、高安全性和长寿命的新型电化学储能体系奠定理论基础并提供技术指导。发表相关研究论文26篇，包括Science Advances, Nature Communications, Angewandte Chemie International Edition, Advance Energy Materials, ACS Energy Letter, Journal of The Electrochemical Society, Science China Chemistry等有重要影响力的专业杂志，完成项目总体预定目标。