A novel reinforced concrete-like composite solid-state electrolyte with enhanced performance for all-solid-state lithium batteries

Due to superior energy density and safety, all-solid-state lithium-ion batteries (ASSLBs) are considered to be the perfect substitute for lithium-ion batteries. As the most important component of ASSLBs, solid-state electrolytes (SSEs) are an important part of promoting the commercial development of ASSLBs. However, low ionic conductivity and poor oxidation stability of SSEs are the main obstacles to their industrial preparation. Here, we chose garnet Li₇La₃Zr₂O₁₂ ceramics to prepare a three-dimensional (3D) rebar-like structure nanofiber framework by electrospinning, and infiltrating a polyethylene oxide (PEO) polymer matrix to form the reinforced concrete-like composite solid electrolytes (3D RC-CSEs). The regularly arranged and interconnected framework endows the 3D RC-CSEs with a fast ion transport channel (ion conductivity is 0.23 mS cm⁻¹ at 30 ℃), the lithium-ion transference number is up to 0.47 and electrochemical stability window of 4.9 V (vs. Li⁺/Li). The Li|3D RC-CSEs|Li battery can achieve a stable cycle for 3200 h at 0.2 mA cm⁻². The LFP|3D RC-CSEs|Li battery shows an excellent rate performance (discharge specific capacity of 123.1 mAh g⁻¹ at 3 C) and great cycling performance (discharge specific capacity of 123.1 mAh g⁻¹ after 600 cycles at 1 C) at 60 ℃. In addition, the 3D RC-CSEs showed that Young's modulus is 9.6 times of the PEO-LiTFSI. The unique structural design provides a practical strategy for commercial development.