Effects of Li+ conduction on the capacity utilization of cathodes in all-solid-state lithium batteries

Zhiping Wang; Shipai Song; Chunzhi Jiang; Yongmin Wu; Yong Xiang; Xiaokun Zhang

doi:10.3389/fchem.2023.1169896

Effects of Li⁺ conduction on the capacity utilization of cathodes in all-solid-state lithium batteries

Front Chem. 2023 Apr 21:11:1169896. doi: 10.3389/fchem.2023.1169896. eCollection 2023.

Authors

Zhiping Wang¹, Shipai Song¹, Chunzhi Jiang¹, Yongmin Wu², Yong Xiang^{1

3

4}, Xiaokun Zhang¹

Affiliations

¹ School of Materials and Energy, University of Electronic Science and Technology of China, Chengdu, Sichuan, China.
² State Key Laboratory of Space Power-sources Technology, Shanghai Institute of Space Power-sources, Shanghai, China.
³ Advanced Energy Research Institute, University of Electronic Science and Technology of China, Chengdu, Sichuan, China.
⁴ Sichuan Provincial Engineering Research Center of Flexible Display Material Genome, University of Electronic Science and Technology of China, Chengdu, Sichuan, China.

Abstract

Li⁺ conduction in all-solid-state lithium batteries is limited compared with that in lithium-ion batteries based on liquid electrolytes because of the lack of an infiltrative network for Li⁺ transportation. Especially for the cathode, the practically available capacity is constrained due to the limited Li⁺ diffusivity. In this study, all-solid-state thin-film lithium batteries based on LiCoO₂ thin films with varying thicknesses were fabricated and tested. To guide the cathode material development and cell design of all-solid-state lithium batteries, a one-dimensional model was utilized to explore the characteristic size for a cathode with varying Li⁺ diffusivity that would not constrain the available capacity. The results indicated that the available capacity of cathode materials was only 65.6% of the expected value when the area capacity was as high as 1.2 mAh/cm2. The uneven Li distribution in cathode thin films owing to the restricted Li+ diffusivity was revealed. The characteristic size for a cathode with varying Li⁺ diffusivity that would not constrain the available capacity was explored to guide the cathode material development and cell design of all-solid-state lithium batteries.

Keywords: Li+ diffusivity; all-solid-state lithium batteries; capacity; cathode; modeling.

Grants and funding

This work was supported partly by the National Science Funds of China (Grant No. 21905040) and startup funds from the University of Electronic Science and Technology of China (Grant No. Y03019023601008001).