Comprehensive Analysis of <scp> ZrO ₂ </scp> Particle Size in <scp>PEO</scp> Electrospun Nanolayers for Enhanced Performance as a Polymeric Solid‐State Electrolyte

ABSTRACT Nanofibrous solid electrolytes (NSEs) represent a highly promising category of architectural designs for next‐generation lithium‐ion batteries, through offering favorable pathways for transferring lithium ions between the interconnected tiny pores. However, the relatively low ionic conductivity observed at room temperature still poses substantial challenges that hinder their practical applications, which could be remarkably addressed by loading fillers, like oxide nanoparticles. Herein, we employed nano‐ and microscaled zirconia (ZrO 2 ) particles with various concentrations (1%–5%) into the polyethylene oxide‐based NSEs to approach a maximized electrochemical functionality. The results indicated a significant rise in the fraction of free lithium ions from 0.21 to 0.72 and 0.44 via loading 3% and 1% nano and micro ZrO 2 , respectively. The Nyquist plots exhibited the highest ionic conductivities of (2.44 ± 0.35) × 10 −4 and (2.54 ± 0.28) × 10 −4 S cm −1 in the presence of 3% and 1% nano and micro ZrO 2 . Additionally, incorporating the fillers resulted in an enhancement in the capacity retention from 98.75 to 151.75 (containing 3% nano ZrO 2 ) and 146.42 mAh g −1 (containing 1% micro ZrO 2 ) at 1C after 80 cycles. The findings illustrate a clear correlation between nanoparticle size and electrolyte performance, suggesting that the incorporation of nanoscale ZrO 2 presents a viable approach to address the intrinsic limitations of PEO‐based NSEs. This research provides valuable insights for the strategic design of high‐performance, flexible, and secure solid‐state electrolytes intended for next‐generation lithium‐ion batteries and other energy storage systems.