Expanded Structural Design of Organic Ionic Plastic Crystals Based on Linear Tris‐Pyrrolidinium Salt
Year: 2025
Type: article
Abstract: Organic ionic plastic crystal (OIPC) materials exhibit soft solid phases within a specific temperature range, making them promising candidates for various electrochemical devices due to their intrinsic ionic conductivity and electrochemical stability. In this study, a series of linear tris‐pyrrolidinium salts with different alkyl side chain lengths and counter‐anions were synthesized and systematically characterized in terms of their structural, thermal, and electrochemical properties. Among the synthesized compounds, N,N ‐bis(4‐( N′ ‐undecylpyrrolidinium)butyl)pyrrolidinium trishexafluorophosphate ( 11‐PF 6 ) exhibited two solid‐solid phase transitions and a low fusion entropy ( ΔS f ) of 13 J·K −1 ·mol −1 at 210 °C. Similarly, N,N ‐bis(4‐( N′ ‐dodecylpyrrolidinium)butyl)pyrrolidinium tris‐hexafluorophosphate ( 12‐PF 6 ) showed multiple phase transitions with a low ΔS f of 18 J·K −1 ·mol −1 at 206 °C. The temperature‐dependent soft crystalline phases of 11‐PF 6 were identified as plastic crystal phase using polarized optical microscopy and 1D wide‐angle X‐ray scattering (WAXS). The ionic conductivity of 11‐PF 6 was measured to be 2.04 × 10 −6 S·cm −1 at 70 °C. Upon blending with 80 mol% LiTf 2 N, the ionic conductivity significantly increased to 1.16 × 10 −4 S·cm −1 . Electrochemical stability was evaluated via linear sweep voltammetry (LSV). The composite solid electrolyte consisting of 11‐PF 6 and 80 mol% LiTf 2 N exhibited electrochemical stability up to 5.4 V (versus Li/Li + ), highlighting its potential as a high‐voltage electrolyte component.
Source: Chemistry - A European Journal
Authors: Jong Chan Shin, Minjae Lee
Institution: Kunsan National University
Language: English
Subfield: Catalysis
Field: Chemical Engineering
Domain: Physical Sciences
Open Access status: bronze
OpenAlex ID: W4410176696