基于固态陶瓷的锂空气电池结构设计及相关问题研究

Recently, “lithium-air batteries” the upgraded products of lithium-ion batteries have attracted an increasing attention in academia and industry. If successfully developed and commercialized, it will have a revolutionary impact on the electric vehicle industry and even electrical energy storage area. But, there are many key issues for lithium-air batteries required to be resolved, such as, volatility, flammability and decomposition issues for organic electrolytes; dendrite formation and surface corrosion for lithium anode; product deterioration at cathode side. Accordingly, we propose a novel solid-state lithium-air batteries that can solve the issues above mentioned. Moreover, this design can address two big concerns for conventional solid-state lithium-air batteries, i.e., high internal resistance and limited TPBs at cathode side. Based on this novel battery, this project will study some scientific issues in-depth, such as, (i) the essence of electrochemical reaction at TPBs of cathode; (ii) the effect of H2O and CO2 on battery performance; and (iii) the stability, oxygen permeability and selectivity of oxygen-selective-membrane. The results can provide experimental basis for in-depth understanding of the electrochemical reaction, provide theoretical support for electrode design, and resulting in a continuing shift from lithium-oxygen batteries to lithium-air batteries.

最近，锂离子电池的升级产品“锂空气电池”吸引了学术界和工业界的广泛关注。如果能最终研发成功并商业化，将对电动汽车行业以及电能存储领域产生革命性的影响。但目前锂空气电池中的很多关键问题都尚未得到解决，如：有机电解液的挥发、易燃、分解；锂负极的枝晶、腐蚀；正极的产物变质等问题。为此，申请人提出一种全新固态锂空气电池，可以全面解决上述问题。此外，通过结构设计解决了传统固态锂空气电池的两大致命问题：高的电池内阻和十分有限的阴极活性位点。本项目将基于这种新型固态锂空气电池，深入研究：（i）锂空气电池在正极三相界面的电化学反应本质；（ii）H2O和CO2对电池性能的影响程度；（iii）透氧膜的稳定性，氧渗透能力和选择能力。从而为深入理解锂空气电池的电化学反应路径提供实验依据，为电极结构设计提供理论支持，不断推进锂氧气电池向锂空气电池的转变。

本项目完成了LLZO的固相和液相合成，通过干压烧结的方式完成了致密LLZO陶瓷片的烧结，最终陶瓷块体的致密度达到95%以上，通过二次酸刻蚀完成双层（LLZO多孔层+LLZO致密层）甚至三层（LLZO多孔层+LLZO致密层+LLZO多孔层）的制备，通过浸渍方式将电子导电层引入多孔层中形成全固态空气阴极，并与LLZO致密层形成电解质阴极一体化结构，完成了锂空气电池的系统测试、表征；此外还完成高效空气电极催化剂、石墨烯基空气电极载体、金属锂阳极制备及保护、有机-陶瓷复合电解质薄膜、氧气渗透膜、锂空气单电池、原理样机等研究内容；突破了复合高效催化剂、复合固体电解质、氧气渗透膜、锂阳极制备及界面保护等关键技术；研制了锂空气电池样机（原理样机），通过试验测试，锂空气电池样机表面积达到50cm2；电流密度为0.1mA/cm2时，容量达到729mAh，样机比能量达到1360Wh/kg，0.1C倍率循环100周容量保持率100%，能量保持率97.5%，技术成熟度达到了4级。项目执行期间申请国家发明专利6项，发表SCI论文34篇，培养博士生3人，硕士生5人。