Bio-Based Solid Polymer Electrolytes From Cellulose Nanocrystal/Chitosan Polyelectrolyte Complexes

• Grant number: 25/25014-1
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate (Direct)
• Start date: March 16, 2026
• End date: September 15, 2026
• Field of knowledge: Physical Sciences and Mathematics - Chemistry - Physical-Chemistry
• Principal Investigator: Watson Loh
• Grantee: Guilherme Henrique Vedovello Silva
• Supervisor: Jodie Lutkenhaus
• Host Institution: Instituto de Química (IQ). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil
• Institution abroad: Texas A&M University, United States
• Associated to the scholarship: 23/07740-1 - Compact Polyelectrolyte Complexes From Polysaccharidic Precursors, BP.DD

Abstract

Biobased solid polymer electrolytes (SPEs) offer a promising pathway toward safer and more sustainable energy storage compared to conventional flammable liquid electrolytes used in Li-ion batteries. Polysaccharides, such as cellulose and chitosan, are particularly attractive building blocks due to their abundance, renewability, biodegradability, and unique physicochemical properties arising from hydrogen bonding networks. This project investigates composite films derived from polyelectrolyte complexes (PECs) of chitosan (CS) and sulfated cellulose nanocrystals (CNC), incorporating poly(ethylene glycol) (PEG), as potential SPEs. We aim to leverage the inherent properties of these biopolymers while addressing SPE challenges like low ionic conductivity. Two systems will be explored: (1) Non-stoichiometric CS:CNC PECs with excess negative charge compensated by Li+ via dialysis, designed to maximize the Li+ transport number; and (2) Lithium bis(trifluoromethanesulfonyl)imide-doped CS:CNC PECs prepared to investigate saloplasticity (the modulation of material properties by doping the ionic crosslinks with salt) as a strategy to potentially enhance polymer chain mobility and ionic transport. Key electrochemical properties, including ionic conductivity (via EIS), electrochemical stability against Li metal (via galvanostatic cycling), and the Li+ transport number (via Bruce-Vincent method), will be systematically characterized. The main objective is to establish structure-property relationships to guide the development of effective biobased SPEs for battery applications.¿