(181s) Structure-Property Relationships in Dynamic Polymer Networks for Electrochemical Applications

Rational design of the electrode-electrolyte interphase is essential to stabilize electrodeposition of reactive metals like lithium, irrespective of the nature of electrolyte (liquid or solid-state). Thus, it is important to design an artificial interfacial layer that can accommodate the stress generation due to the volume changes during battery operation and at the same time maintain ionic continuity. In our work, we design novel materials based on stimuli-responsive polymeric architectures that can be used as a sandwich phase between the electrolyte and metal anode for enhancing the electrochemical stability. It was seen that polymers comprising of dynamic bonding groups are more effective in preventing the morphological instabilities compared to covalently bonded rigid polymers and crosslinked elastomers. The stabilization mechanism of the dynamic polymeric coatings is understood to arise from the spontaneous structural response of the polymer in response to the roughening electrode during electrodeposition. As the polymer coating is free to flow, if there is a ‘hotspot’ (uneven deposit) on the surface of the lithium metal, the dynamic polymer coating can rearrange and cover these regions resulting in increased overpotential, such that the successively Li⁺ ions deposit on the flatter regions resulting in uniformity of deposition. In my talk, I will discuss the rheology, dielectric properties and NMR relaxation behaviors of these dynamic polymer networks and the relationship with their electrochemical functions.