Strain-Tolerant Heteroepitaxial LiCoO₂/Pt on Mica for Interfacial Engineering for Enhanced Oxygen Evolution Catalysis.

In this work, we demonstrate a novel heteroepitaxial lithium cobalt oxide (LiCoO₂)/Pt architecture on flexible mica substrates that simultaneously achieves exceptional catalytic activity, durability, and mechanical flexibility. Through precise control of LiCoO₂ thickness (optimized at 190 nm), we fabricate an electrode exhibiting outstanding oxygen evolution reaction (OER) performance: a low overpotential of 308 mV at 10 mA cm⁻², a Tafel slope of 45 mV dec⁻¹, and remarkable stability with 97% activity retention after 30 hours in alkaline media. Especially, in-situ Raman spectroscopy investigations provide unprecedented insight into the dynamic structural evolution at the electrode-electrolyte interface, suggesting the formation of interfacial Co-O-Pt-like bonding environments. The flexible heterostructure maintains its exceptional performance even after 1,000 severe bending cycles at 5 mm radius (33% strain), demonstrating negligible degradation in linear sweep voltammetry measurements. This exceptional mechanical durability stems from the unique heteroepitaxial growth that prevents delamination under strain. Beyond presenting a high-performance flexible OER electrode, this work establishes several important design principles: (i) the critical role of lattice-matched substrates in strain-tolerant electrocatalysts, (ii) the importance of controlled epitaxial growth for interface engineering, and (iii) the value of in-situ spectroscopic techniques for understanding reaction mechanisms. These findings open new avenues for developing advanced flexible energy materials through heteroepitaxial design strategies.