Poly(Ionic) Liquid-Enhanced Ion Dynamics in Cellulose-Derived Gel Polymer Electrolytes

Area of Science:

• Materials Science
• Electrochemistry
• Polymer Science

Background:

• Gel polymer electrolytes (GPEs) offer advantages over conventional electrolytes by combining solid and liquid properties.
• Cellulose-based materials are abundant, eco-friendly, and suitable for developing advanced GPEs.

Purpose of the Study:

• To develop cellulose-based GPEs using methyl cellulose and various ionic liquid dopants.
• To investigate the influence of different dopants on ion dynamics and molecular interactions in GPEs.
• To evaluate the performance of these GPEs in micro supercapacitor devices.

Main Methods:

• GPEs synthesized using methyl cellulose, ionic liquids ([Pyr14][TFSI]), polymeric ionic liquids ([PDADMA][TFSI]), and anionic polymeric ionic liquids (LiP[STFSI]).
• Characterization via Attenuated Total Reflectance Fourier-Transform Infrared Spectroscopy (ATR-FTIR), Heteronuclear Overhauser Enhancement Spectroscopy (HOESY), and Pulsed-Field Gradient Nuclear Magnetic Resonance Diffusion (PFG-NMR).
• Calculation of Li+ transference numbers (tLi+).

Main Results:

• GPEs incorporating slow-diffusing polymeric ionic liquids and fast-diffusing lithium salts achieved high Li+ transference numbers.
• The anionic polymeric ionic liquid (LiP[STFSI]) significantly enhanced lithium-ion transport, yielding transference numbers comparable to liquid electrolytes.
• Micro supercapacitors (MSCs) fabricated with these GPEs demonstrated capacitive behavior.

Conclusions:

• The nature of the polymer dopant critically influences lithium-ion transport in GPEs.
• Optimized GPEs show potential for enhancing performance in sustainable energy storage systems.
• Further development of GPE composition can lead to improved efficiency for applications like micro supercapacitors.