A poly(ether block amide) based solid polymer electrolyte for solid-state lithium metal batteries

Solid-state lithium (Li) metal batteries (SSLMBs) with high-energy density and high-security are promis-ing for energy storage application and electronic device development. However, Li dendrite generation is still one of the most important factors hindering the application of SSLMBs since interface contact degra-dation, dead Li accumulation, and continuous solid-electrolyte interphase (SEI) growth are always caused by Li dendrite growth, making the performances of SSLMBs deteriorate rapidly. In this study, a poly(ether block amide) (PEBA) based polymer electrolyte with lithium bis-(trifluoromethanesulfonyl)imide (LiTFSI) as the Li salt is developed. It is found that the PEBA 2533-20% LiTFSI electrolyte possesses an ion conduc-tivity of 3.0 x 10-5 S cm -1 at 25 degrees C. Especially, the Li dendrite suppression ability of SEI is greatly enhanced since it provides abundant amide groups to activate TFSI- anions and further enriches lithium fluoride (LiF) content in the SEI layer, which endows the full-cell with enhanced cyclability. As a result, the fabricated solid-state Li/PEBA 2533-20% LiTFSI/LiFePO4 (areal capacity: 0.15 mAh cm -2) battery remains 94% of its maximum capacity (127.5 mAh g-1) at a rate of 0.5C and 60 degrees C after 200 cycles. In par-ticular, the full cell can cycle for almost 1000 times without short circuit. Therefore, the PEBA based elec-trolyte could promote the LiF enriched SEI layer into a platform to suppress the growth of Li dendrite toward SSLMBs with a long-life span.(c) 2022 Elsevier Inc. All rights reserved.