实用化高比能准固态锂离子电池体系的研究

Research on practical high-specific energy quasi-solid-state lithium-ion battery system

针对锂离子电池中电解液易泄漏、易燃烧,甚至引发爆炸等潜在安全问题,本文将单一的醚类小分子物质作为单体,与LiPF_(6)基电解液混合制备预聚前驱体,在60℃下原位衍生为非流动态的黏弹性凝聚体。通过调控单体比例、优化原位固化工艺,制备出高镍/高硅准固态锂离子电池。经测试,2.1 Ah电池体系在0.3 C电流下循环寿命达600圈,保持率比同期液态高1.8%。由更高硅含量的负极构成的36 Ah电池体系的比能量高达351 Wh/kg,500圈循环容量保持率达88.36%,准固态锂离子电池具有优异的低温性能,-20℃下容量保持率达85.6%,结果表明固化电解质在电池层内部及层间起到了良好的结构稳定性作用。该高比能准固态锂离子电池体系的开发为后续固态电池的进一步实用化提供了切实可行的途径。

Aiming at the potential safety problems such as electrolyte leakage,combustion and explosion in lithium-ion batteries,our work prepared an ether based prepolymer precursor,which were prepared by mixing a single ether molecule monomer with LiPF_(6)-based electrolyte,and then derived a non-flow viscoelastic aggregate in situ at 60℃.By adjusting the monomer ratio and optimizing the in situ curing process,we prepared a high nickel/high silicon quasi-solid-state lithium ion battery.Our results show that the cycle life of 2.1 Ah battery system can reach 600 cycles at 0.3 C,and the retention rate is 1.8%higher than that of liquid battery in the same system.The 36 Ah battery based on the anode with higher silicon content has the highest specific energy of 351 Wh/kg and the capacity retention rate of 88.36%after 500 cycles.The quasi-solid-state lithium-ion battery shows excellent low temperature performance with the capacity retention rate of 85.6%at-20℃.The results show that the solidified electrolytes play a good role in the structural stability of the battery layer and interlayer.The development of the high specific energy quasi-solid-state lithium-ion battery system provides a feasible way for the further practical application of the subsequent energy storage solid-state battery.