Vertically Aligned and Continuous Nanoscale Ceramic–Polymer Interfaces in Composite Solid Polymer Electrolytes for Enhanced Ionic Conductivity

TLDR

Composite solid polymer electrolytes with ceramic fillers enhance ionic conductivity and mechanical properties through ceramic–polymer interactions. The study reports a composite electrolyte featuring densely packed, vertically aligned, continuous nanoscale ceramic–polymer interfaces built on surface‑modified anodized aluminum oxide scaffolds and a poly(ethylene oxide) matrix. The authors fabricated the electrolyte by embedding surface‑modified anodized aluminum oxide scaffolds into a poly(ethylene oxide) matrix to create continuous interfacial pathways. Experimental results show fast Li⁺ transport along the interfaces, with interfacial ionic conductivity exceeding 10⁻³ S cm⁻¹ at 0 °C and an overall electrode‑level conductivity of 5.82 × 10⁻⁴ S cm⁻¹, enabling Li–Li cells to cycle at low polarization without dendrite penetration due to the high‑hardness, vertically aligned interfacial structure.

Abstract

Among all solid electrolytes, composite solid polymer electrolytes, comprised of polymer matrix and ceramic fillers, garner great interest due to the enhancement of ionic conductivity and mechanical properties derived from ceramic-polymer interactions. Here, we report a composite electrolyte with densely packed, vertically aligned, and continuous nanoscale ceramic-polymer interfaces, using surface-modified anodized aluminum oxide as the ceramic scaffold and poly(ethylene oxide) as the polymer matrix. The fast Li+ transport along the ceramic-polymer interfaces was proven experimentally for the first time, and an interfacial ionic conductivity higher than 10-3 S/cm at 0 °C was predicted. The presented composite solid electrolyte achieved an ionic conductivity as high as 5.82 × 10-4 S/cm at the electrode level. The vertically aligned interfacial structure in the composite electrolytes enables the viable application of the composite solid electrolyte with superior ionic conductivity and high hardness, allowing Li-Li cells to be cycled at a small polarization without Li dendrite penetration.