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Development of vitrimers for solid-state polymer electrolytes by Swetha Karingal Veedu -
Jeudi 17 septembre 2026 à 14h00 - Auditoire A03 SCES - Place des Sciences, 2 - 1348 Louvain-la-Neuve -
Abstract: Solid polymer electrolytes (SPEs) are key candidates for high energy density lithium metal batteries due to their improved safety compared to liquid electrolytes. Among the various polymer hosts, poly(ethylene oxide) (PEO) remains the most widely studied. However, PEO-based SPEs still face challenges such as low ionic conductivity at room temperature and poor mechanical properties. Crosslinked networks with permanent covalent bonds can improve mechanical stiffness but lack self-healing and reprocessability. Vitrimer based SPEs could overcome these limitations through exchangeable covalent bonds that enable topology rearrangement and flow under elevated temperatures while maintaining a constant crosslink density.
This thesis exploits vitrimer chemistry to design poly(ethylene glycol) (PEG) based SPEs and investigates the structure-property relationships governing network relaxation dynamics, mechanical properties, and ionic conductivity. Two types of dynamic covalent bonds, disulfide and boronic ester, are explored across different network topologies. The disulfide-based networks required the addition of a catalyst to trigger the exchange reaction, and only an onset of relaxation was observed within the measured temperature range. In addition, the system was prone to undergo radical-mediated side reactions, leading to irreversible crosslinks. The boronic ester-based networks showed that the introduction of dioxazaborocane moieties significantly enhanced the exchange dynamics compared to dioxaborolane, and these networks exhibited dynamic behaviour within the measured temperature range (25-120 ℃). The addition of Li salt influenced the exchange dynamics differently depending on the network topologies studied. Moreover, no correlation was observed between the exchange dynamics of the boronic esters and the ionic conductivity of the SPE. These results suggest that the bond exchange dynamics and ion transport are decoupled processes in this electrolyte system.
Jury members :
Prof. Charles-André Fustin (UCLouvain) (Supervisor)
Prof. Evelyne van Ruymbeke (UCLouvain) (Co-supervisor)
Prof. Arnaud Delcorte (UCLouvain) (President)
Prof. Jean-François Gohy (UCLouvain) (Secretary)
Prof. Renaud Nicolaÿ (ESPCI Paris, Fr.)
Dr. Marc Guerre (Toulouse University, Fr.)
Pay attention : the public defense of Swetha Karingal Veedu will also take place in the form of a videoconference
