Room Temperature to 150 °C Lithium Metal Batteries Enabled by a Rigid Molecular Ionic Composite Electrolyte. Issue 12 (9th February 2021)

• Record Type: Journal Article
• Authors: Yu, Deyang; Pan, Xiaona; Bostwick, Joshua E.; Zanelotti, Curt J.; Mu, Linqin; Colby, Ralph H.; Lin, Feng; Madsen, Louis A.
• Is Part Of: Advanced energy materials. Volume 11:Issue 12(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-02-09
• Subjects: high temperature -- ionic liquids -- lithium batteries -- molecular ionic composites -- polymer electrolytes; Energy harvesting -- Materials -- Periodicals; Energy conversion -- Materials -- Periodicals; Energy storage -- Materials -- Periodicals; Photovoltaics -- Periodicals; Fuel cells -- Periodicals; Thermoelectric materials -- Periodicals; 621.31
• DOI: 10.1002/aenm.202003559
• Languages: English
• ISSNs: 1614-6832

Abstract

Abstract: Molecular ionic composites (MICs), made from ionic liquids and a rigid‐rod polymer poly(2, 2′‐disulfonyl‐4, 4′‐benzidine terephthalamide) (PBDT), are a new type of rigid gel electrolyte that combine fast ion transport with high thermal stability and mechanical strength. In this work, a MIC electrolyte membrane is prepared that is composed of PBDT, lithium bis(trifluoromethylsulfonyl)imide (LiTFSI), and 1‐butyl‐1‐methylpyrrolidinium bis(trifluoromethylsulfonyl)imide (Pyr14 TFSI) in a mass ratio of 10:10:80. The ionic conductivity at 25 ° C is 0.56 mS cm −1 with no added flammable/volatile components. Although the polymer content is only 10 wt%, this MIC membrane is rigid with a tensile modulus of 410 MPa at room temperature. The MIC membrane remains stable and rigid at 200 ° C with the shear storage modulus ( G ′) only slightly decreasing by 35%. Li/MIC/LiFePO4 cells demonstrate stable cycling performance over a wide temperature range from 23 to 150 ° C. The specific discharge capacity at 100 and 150 ° C at 1 C rate exceeds 160 mAh g −1 . The discharge capacity retention is 99% after 50 cycles at 150 ° C. This stable battery performance shows that this low polymer content MIC membrane qualifies for use as a solid electrolyte in lithium metal batteries operating over a wide temperature range. Abstract : A new type of ionic liquid gel electrolyte is made with a rigid aromatic polyamide. The solid electrolyte, containing only 10 wt% polymer, is rigid and remains mechanically stable up to 200 °C. Li/MIC/LiFePO4 batteries show stable cycling performance over a wide temperature range, from 23 to 150 °C.