Electrochemical characterization of in situ polymerized composite solid electrolyte incorporating three dimensional Li1·5Al0.5Ge1.5(PO4)3 framework.

In pursuit of safer lithium-ion batteries, research is veering towards all-solid-state lithium batteries (ASSLBs) featuring solid electrolytes due to the safety concerns and low metal interfacial compatibility of liquid electrolytes. ASSLBs combined with composite solid electrolytes (CSEs) incorporating NASICON-type active fillers are especially appealing because of their inherent safety, ease of production, and high energy density. This study introduces a Li 1 · 5 Al 0.5 Ge 1.5 (PO 4) 3 (LAGP) framework created via tape casting and in situ thermal polymerization, achieving a CSE with notable ionic conductivity (0.791 mS cm−1), electrochemical stability up to 5.09 V, and a lithium-ion transference number of 0.72 at 30 °C. The Li|CSE|Li cell demonstrates low overpotential over 1000 h, and the Li|CSE|NCM811 coin cell delivers a discharge capacity of 180.9 mAh g−1, maintaining 84.6 % capacity after 200 cycles. Moreover, the Li|CSE|NCM811 pouch cell upholds a capacity of 116.41 mAh g−1 after 100 cycles, underscoring the 3D LAGP framework and in situ polymerization's role in enhancing ASSLB safety and functionality. The composite solid electrolyte, synthesized through a straightforward one-step in-situ polymerization process within a three-dimensional LAGP framework, exhibits excellent ionic conductivity and demonstrates superior electrochemical performance in all-solid-state lithium batteries. [Display omitted] • Composite Solid Electrolyte with 3D LAGP framework is synthesized. • The CSE showed the ionic conductivity of 7.91 × 10−4 S cm−1 at 30 °C. • The Li.|CSE|Li cell shows excellent stability over 1000 h with low over potential. • The Li.|CSE|NCM cell delivers excellent rate capability, and long cyclability. • The coin and pouch type cells show the applicability of the CSE. [ABSTRACT FROM AUTHOR]