Impact of Li1.3Al0.3Ti1.7(PO4)3 content and particle size on the electrochemical properties and stability of polymer-based solid electrolytes for lithium batteries

Abstract

This work addresses the current limitations of standard composite solid electrolyte membranes through a systematic optimization of the LATP Li 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 wt fraction and rigorous particle size control via selective milling. By precisely integrating these calibrated ceramic particles within a ternary PVDF-HFP/PEO matrix, the resulting configuration establishes a highly balanced framework for advanced lithium-ion battery applications. The optimal composition, designated CSE2H (26 wt% LATP with particle size d 50 ≈ 0.875 μm), exhibits exceptional electrical properties: minimum activation energy (0.138 eV), maximum ionic conductivity (1.12·10 −4 S cm −1 at 30 °C and 6.33·10 −4 S cm −1 at 70 °C), and stable electrochemical operation within the voltage range 2.5-4.2 V vs. Li + /Li, LFP-cell operating conditions. Electrochemical impedance spectroscopy reveals low interfacial resistance, while chronoamperometry measurements yield a lithium-ion transference number of 0.48, indicating efficient ion transport. Galvanostatic cycling experiments confirm high coulombic efficiency (98%) and good capacity retention: initial capacity of 147 mAh g −1 LFP at 0.5C stabilizing at 77.58 mAh g −1 LFP after 200 cycles, with specific discharge capacity of 127.2 mAh g −1 LFP at 2C. Concurrently, these integrated results establish that this 26 wt% LATP baseline configuration successfully balances interfacial compatibility with competitive electrochemical properties, presenting a highly viable pathway for targeted solid-state battery development.