Electro-chemo-mechanical deterioration of high-dose electron irradiated Li1.3Al0.3Ti1.7(PO4)3 electrolyte

Solid-state electrolytes (SSEs) hold promises for aerospace and satellite applications, owing to their high-voltage and low-temperature stability. However, concerns about electrochemical degradation under high-energy radiation hinder their widespread use in space. To this end, a NASICON-type Li1.3Al0.3Ti1.7(PO4)3 (LATP) electrolyte with high ionic conductivity at room temperature was selected, and the effects of high-dose electron irradiation on the microstructure as well as electrochemical and mechanical properties of electrolyte were investigated by using neutron powder diffraction (NPD), NPD stress analysis, micro-computed tomography, nanoindentation, and XRD residual stress test. It was confirmed that LATP SSEs held good resistance to irradiation at absorbed doses of 1 and 2 MGy with negligibly performance degradation, while irradiation at high doses induced a rapid decrease in the Young modulus and hardness of SSEs and introduced a tensile stress of 65.79 MPa at up to 10 MGy absorbed dose, which increased the cracking tendency and the risk of lithium dendrite growth in the solid-state electrolyte. NPD revealed that the reduction of lithium vacancies at the M1 site of the irradiated SSEs was the critical factor for the ion transport performance degradation. This is evidenced by a significant increase in impedance, up to 453 Ω, and an increase in the activation energy for ion transport to 0.501 eV.