Hybrid Electrolyte of Li_1.3Al_0.3Ti_1.7(PO₄)₃ Nanofibers and Cross-linked Gel Electrolyte for Li Metal Batteries

Hybrid solid electrolytes (HSEs) based on oxide-based inorganic electrolytes in combination with polymer electrolytes or gel electrolytes are promising options for lithium batteries. Utilizing the synergistic combination of the two materials, HSEs offer great potential to achieve high ionic conductivity, reduced interfacial resistance, mechanical integrity, and high processability. Despite the enhanced performances by the hybrid designs, the reason for the enhancement has not been fully understood. Herein, we report an HSE consisting of a three-dimensional (3D) network of Li1.3Al0.3Ti1.7(PO4)3(LATP) nanofibers and a UV-cured gel electrolyte in comparison with an LATP powder-dispersed and an LATP-free UV-curved gel electrolyte to elucidate the role of the 3D LATP network in enhancing the performance of lithium metal batteries. The LATP fiber was prepared by electrospinning LATP powder and polyacrylonitrile without calcination. The incorporation of the LATP fiber network to the gel electrolyte increases the ionic conductivity and Li+ transference number due to the interfacial Li+ conduction between the fibers and the gel electrolyte. The LATP fiber and powder-dispersed gel electrolytes show a change in the SEI structure; however, the former exhibits a more uniform Li deposition morphology, longer cycling stability, and higher rate capability, demonstrating the critical role of the interfacial conduction.