Cross-Linked Polymer Electrolytes for Li-Based Batteries: From Solid to Gel Electrolytes

Abstract

We report the preparation of solvent-free polymer electrolytes via a free radical copolymerization of methacrylate-based oligomers in the presence of LiTFSI. Properties of the electrolytes were then studied as a function of their compositions. Furthermore, the incorporation of a room temperature ionic liquid (RTIL) into the copolymer electrolyte to form a gel polymer electrolyte (GPE) is also reported. The high miscibility of the oligomers in the RTIL enables the preparation of the GPEs by a one-step method using the in situ free radical copolymerization. The GPEs have a dry aspect and are free-standing; they also exhibit an ionic conductivity close to 4 × 10–4 S cm–1 at 25 °C and to 1.45 × 10–3 S cm–1 at 65 °C. Furthermore, the GPEs have been used as electrolytes in a Li/Electrolyte/LiNi1/3Mn1/3Co1/3O2 battery. Specific capacities of 79 mAh g–1 and 118 mAh g–1 were reached at the C/5 and C/10 rate, respectively.

Rechargeable Thin‐Film Lithium Microbattery Using a Quasi‐Solid‐State Polymer Electrolyte

“…The encapsulation of the liquid phase by the polymer therefore lowered the modulus E and the stress at break; however, it improved elongation at break. These results confirm the plasticizing effect of the liquid phase on the polymer matrix, this character agreeing with the results obtained by DSC, [54] where we measured the glass transition temperature of a similar mixture without PVdF‐HFP, and observed lowering of the glass transition temperature, T g during the addition of the ionic liquid.…”

An enhanced electrochemical and cycling properties of novel boronic Ionic liquid based ternary gel polymer electrolytes for rechargeable Li/LiCoO2 cells

“…The cycling performance at C /10 rate, with a discharge capacity of 148.4 mAh g −1 , is apparently good. However, the discharge capacity faintly decreases to 130 and 118 mAh g −1 at C /2 and 1 C rates, respectively which is from 84 to 36% of the theoretical capacity for active material LiCoO 2 53 , 54 . The reversibility of the electrolyte is at 87, 54 and 40% for C /10, C /5 and 1 C rates, respectively.…”

Solid Polymer Electrolytes with High Conductivity and Transference Number of Li Ions for Li‐Based Rechargeable Batteries

“…[ 237–239 ] Scientific research on transparent SPEs is ongoing, and several transparent battery prototypes have already been reported in the literature. [ 136,240–247 ]…”