Artificial solid electrolyte interphase composed of a tris(2-acryloyloxyethyl) isocyanurate-based polymer for lithium metal anode

Abstract

To enhance the mechanical robustness of artificial solid electrolyte interphases (SEIs), particularly their resistance to swelling in liquid electrolytes, we developed a cross-linked polymer coating derived from tris(2-acryloyloxyethyl) isocyanurate (TAIC) and trimethylolpropane ethoxylate triacrylate (ETPTA) for lithium metal anodes. The TAIC : ETPTA (3 : 1)-based polymer exhibited excellent film-forming ability, mechanical stability, and interfacial compatibility with lithium metal. Symmetric cell tests demonstrated prolonged cycling stability exceeding 3500 hours (equivalent to 350 charge–discharge cycles), and a high lithium ion transference number (t_Li+ = 0.75). Furthermore, the polymer film effectively suppressed dendritic lithium growth and minimized electrolyte decomposition. Electrochemical impedance spectroscopy and surface morphology analysis revealed that the coating reduced SEI thickening and interfacial resistance growth during cycling. This work presents a rational design of a mechanically and ionically optimized artificial SEI, offering a viable strategy for stabilizing lithium metal electrodes in high-energy-density batteries such as lithium–sulfur systems.