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Enabling High Lithium Conductivity in Polymerized Ionic Liquid Block Copolymer Electrolytes
Author(s) -
Goujon Nicolas,
Huynh TanVu,
Barlow Kristine j.,
Kerr Robert,
Vezzù Keti,
Di Noto Vito,
O'Dell Luke A.,
Chiefari John,
Howlett Patrick C.,
Forsyth Maria
Publication year - 2019
Publication title -
batteries and supercaps
Language(s) - English
Resource type - Journals
ISSN - 2566-6223
DOI - 10.1002/batt.201800104
Subject(s) - electrolyte , copolymer , lithium (medication) , materials science , ionic liquid , ionic conductivity , conductivity , imide , electrochemistry , polymerization , chemical engineering , ternary operation , polymer chemistry , polymer , inorganic chemistry , chemistry , electrode , organic chemistry , composite material , catalysis , medicine , engineering , endocrinology , computer science , programming language
Herein, the use of a novel block copolymer host, based on a polymerized ionic liquid block copolymer, is proposed. Mechanically robust solid polymer electrolytes (SPEs) with high lithium conductivity are developed using a ternary polymer electrolyte system, consisting of a poly(styrene‐ b ‐1‐((2‐acryloyloxy)ethyl)‐3‐butylimidazolium bis(trifluoromethanesulfo‐nyl)imide) (S‐PIL 64‐16 ) block copolymer, a N ‐propyl‐ N ‐methylpyrrolidinium bis(fluorosulfonyl)imide (C 3 mpyrFSI) ionic liquid (IL) and a lithium bis (fluorosulfonyl) imide (LiFSI) salt. The impact of both IL and lithium salt concentration on the morphology, ion migration processes and electrochemical performance of the electrolytes is characterized. High lithium ion conductivity is achieved when anion to Li + molar ratio was kept below a value of 1.5, resulting in a lithium transport number ( tL i + ) as high as 0.53 at 50 °C. Finally, the cycling performance in a Li|LiFePO 4 full cell is assessed using an in‐house formulated solid‐state high loading cathode (LiFePO 4 loading=10 mg cm −2 , 1.8 mAh cm −2 ). 98 % of the theoretical discharge capacity (167 mA g −1 ) is achieved for the first cycle at a C‐rate of C/20 at 50 °C. The results herein reported are the first demonstration of a PIL block copolymer‐IL‐salt composite electrolyte operating at near‐practical levels, making them a promising choice of electrolyte for the next generation of solid‐state high capacity lithium‐metal batteries.