Solid Electrolytes for Li-S Batteries: Solid Solutions of Poly(ethylene oxide) with Li x PON- and Li x SiPON-Based Polymers

Eleni Temeche; Xinyu Zhang; Richard M Laine

doi:10.1021/acsami.0c06196

Solid Electrolytes for Li-S Batteries: Solid Solutions of Poly(ethylene oxide) with Li _x PON- and Li _x SiPON-Based Polymers

ACS Appl Mater Interfaces. 2020 Jul 8;12(27):30353-30364. doi: 10.1021/acsami.0c06196. Epub 2020 Jun 22.

Authors

Eleni Temeche¹, Xinyu Zhang¹, Richard M Laine¹

Affiliation

¹ Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109-2136, United States.

PMID: 32519843
DOI: 10.1021/acsami.0c06196

Abstract

We report here efforts to synthesize free-standing, dry polymer electrolytes that exhibit superior ionic conductivities at ambient for Li-S batteries. Co-dissolution of poly(ethylene oxide) (PEO) (M_n 900k) with Li_xPON and Li_xSiPON polymer systems at a ratio of approximately 3:2 followed by casting provides transparent, solid-solution films 25-50 μm thick, lowering PEO crystallinity, and providing measured impedance values of 0.1-2.8 × 10^-3 S/cm at ambient. These values are much higher than simple PEO/Li⁺ salt systems. These solid-solution polymer electrolytes (PEs) are (1) thermally stable to 100 °C; (2) offer activation energies of 0.2-0.5 eV; (3) suppress dendrite formation; and (4) enable the use of lithium anodes at current densities as high as 3.5 mAh/cm². Galvanostatic cycling of SPAN/PEs/Li cell (SPAN = sulfurized, carbonized polyacrylonitrile) shows discharge capacities of 1000 mAh/g_sulfur at 0.25C and 800 mAh/g_sulfur at 1C with high coulumbic efficiency over 100 cycles.

Keywords: LiPON; PEO; lithium−sulfur battery; polymer electrolyte; polymer precursors.