Constructing Li‐Rich Artificial SEI Layer in Alloy–Polymer Composite Electrolyte to Achieve High Ionic Conductivity for All‐Solid‐State Lithium Metal Batteries. Issue 11 (29th January 2021)

• Record Type: Journal Article
• Authors: Liu, Yuxuan; Hu, Renzong; Zhang, Dechao; Liu, Jiangwen; Liu, Fang; Cui, Jie; Lin, Zuopeng; Wu, Jinsong; Zhu, Min
• Is Part Of: Advanced materials. Volume 33:Issue 11(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-01-29
• Subjects: all‐solid‐state lithium‐ion batteries -- artificial solid electrolyte interface -- composite polymer electrolytes -- lithium metal batteries -- lithium–silicon alloys -- poly(ethylene oxide); Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adma.202004711
• Languages: English
• ISSNs: 0935-9648

Abstract

Abstract: To achieve high ionic conductivity for solid electrolyte, an artificial Li‐rich interface layer of about 60 nm thick has been constructed in polymer‐based poly(ethylene oxide)‐lithium bis(trifluoromethanesulfonyl)imide composite solid electrolyte (briefly noted as PEOm ) by adding Li‐based alloys. As revealed by high‐resolution transmission electron microscopy and electron energy loss spectroscopy, an artificial interface layer of amorphous feature is created around the Li‐based alloy particles with the gradient distribution of Li across it. Electrochemical analysis and theoretical modeling demonstrate that the interface layer provides fast ion transport path and plays a key role in achieving high and stable ionic conductivity for PEOm ‐Li21 Si5 composite solid electrolyte. The PEOm ‐5%Li21 Si5 composite electrolyte exhibits an ionic conductivity of 3.9 × 10 –5 S cm −1 at 30 ° C and 5.6 × 10 −4 S cm −1 at 45 ° C. The LiFePO4 | PEOm ‐5%Li21 Si5 | Li all‐solid‐state batteries could maintain a stable capacity of 129.2 mA h g −1 at 0.2 C and 30 ° C after 100 cycles, and 111.3 mA h g −1 after 200 cycles at 0.5 C and 45 ° C, demonstrating excellent cycling stability and high‐rate capability. Abstract : A Li‐rich artificial solid electrolyte interface (SEI) layer about 60 nm thick is successfully designed and constructed in a Li alloy filled poly(ethylene oxide) polymer electrolyte to achieve high ionic conductivity for lithium metal batteries. The LiFePO4 |Li all‐solid‐state batteries exhibit high cycling performance of 111.3 mA h g –1 after 200 cycles at 0.5 C in 45 °C.