Liu Jian, Lin Jingyi, Yin Zuwei, Tong Zhen, Liu Junke, Wang Zhen, Zhou Yao, Li Juntao
College of Energy, Xiamen University, Xiamen 361102, China.
Molecules. 2024 Jun 22;29(13):2975. doi: 10.3390/molecules29132975.
In conventional lithium-ion batteries (LIBs), the active lithium from the lithium-containing cathode is consumed by the formation of a solid electrolyte interface (SEI) at the anode during the first charge, resulting in irreversible capacity loss. Prelithiation additives can provide additional active lithium to effectively compensate for lithium loss. Lithium oxalate is regarded as a promising ideal cathode prelithiation agent; however, the electrochemical decomposition of lithium oxalate is challenging. In this work, a hollow and porous composite microsphere was prepared using a mixture of lithium oxalate, Ketjen Black and transition metal oxide catalyst, and the formulation was optimized. Owing to the compositional and structural merits, the decomposition voltage of lithium oxalate in the microsphere was reduced to 3.93 V; when being used as an additive, there is no noticeable side effect on the performance of the cathode material. With 4.2% of such an additive, the first discharge capacity of the LiFePO4‖graphite full cell increases from 139.1 to 151.9 mAh g, and the coulombic efficiency increases from 88.1% to 96.3%; it also facilitates the formation of a superior SEI, leading to enhanced cycling stability. This work provides an optimized formula for developing an efficient prelithiation agent for LIBs.
在传统锂离子电池（LIBs）中，含锂阴极中的活性锂在首次充电时会因阳极处固体电解质界面（SEI）的形成而被消耗，导致不可逆的容量损失。预锂化添加剂可以提供额外的活性锂，以有效补偿锂损失。草酸锂被认为是一种很有前景的理想阴极预锂化剂；然而，草酸锂的电化学分解具有挑战性。在这项工作中，使用草酸锂、科琴黑和过渡金属氧化物催化剂的混合物制备了一种中空多孔复合微球，并对配方进行了优化。由于其组成和结构优点，微球中草酸锂的分解电压降低到了3.93 V；用作添加剂时，对阴极材料的性能没有明显的副作用。添加4.2%的这种添加剂时，LiFePO4‖石墨全电池的首次放电容量从139.1 mAh g增加到151.9 mAh g，库仑效率从88.1%提高到96.3%；它还促进了优质SEI的形成，从而提高了循环稳定性。这项工作为开发一种高效的LIBs预锂化剂提供了优化配方。
