Rearrangement of Ion Transport Path on Nano-Cross-linker for All-Solid-State Electrolyte with High Room Temperature Ionic Conductivity.

Abstract

The low room temperature ionic conductivity (RTσ) of polyethylene oxide (PEO)-based solid-state polymer electrolyte (SPE) severely restricts its application for lithium batteries. Herein, acrylamide (AM) has been introduced into the poly(ethylene glycol) methyl ether methacrylate-poly(ethylene glycol) diacrylate (P-P). The multiple hydrogen bonds of AM expand the original single lithium environment (Li···O-C) to three types (Li···O-C, Li···N-H, and Li···O═C), which accelerates the conduction of lithium ions. In addition, the double bond modification of nanosilica (═SiO2) not only improves the mechanical properties but also brings a high-speed orderly vehicular transport mechanism. The multiple-lithium-ions environment is rearranged on the surface of the ═SiO2 to play a more significant role, making the RTσ of SPE reach 2.6 × 10-4 S cm-1, and the Li-ion transfer number reaches 0.84. The results show that the assembled all-solid-state lithium-sulfur battery has a high initial discharge capacity of 707 mAh g-1 at 30 °C when the sulfur loading is 4.3 mg cm-2, good cycle stability (capacity retention rate of 89% after 100 cycles at 0.1 C), and excellent rate performance. This SPE with high RTσ, stable interface engineering, and broad potential window (5.1 V) is expected to be used in other lithium/lithium-ion batteries that require high-voltage tolerance.