3D printed composite solid electrolytes for high-performance solid-state batteries

Ionic conductive filler-modified composite solid electrolytes (CSEs) are promising electrolytes for solid-state lithium metal batteries. However, traditional methods, such as the roll or transfer coating, often lead to disordered polymer matrices and agglomerated particles, impacting their mechanical strength and lithium ion transport efficiency. Herein, we report a novelty CSE prepared by coupling the 3D printing method with in-situ polymerization technology. The Polyvinylidene fluoride (PVDF) matrix with lithium-aluminum-titaniumphosphate (LATP) fillers is printed into a strip array structure. After an in-situ modification, the result CSEs (CSE-3D) with the arrayed structure exhibit a high ionic conductivity of 3.4 x 10-4 S cm- 1 at room temperature and an ion migration number of 0.77. Additionally, such unique modular structures lead to even dispersion of stress and Li+ flux, confirmed by Ansys and COMSOL simulation, resulting in the CSE-3D exhibiting high mechanical strength of exceeding 50 MPa, exceptional structure stability during the stretching process, and even deposition/striping of lithium. Therefore, the lithium symmetric battery with CSE-3D exhibits stable cycles over 2500 h at 0.1 mA cm- 2 and room temperature. The corresponding LiFePO4/Li batteries also show good cycle performance and rate performance at room temperature. This study proposed a novel solution for the preparation of CSEs in high precision.