HKUST-1@IL-Li Solid-state Electrolyte with 3D Ionic Channels and Enhanced Fast Li+ Transport for Lithium Metal Batteries at High Temperature

The challenge of safety problems in lithium batteries caused by conventional electrolytes at high temperatures is addressed in this study. A novel solid electrolyte (HKUST-1@IL-Li) was fabricated by immobilizing ionic liquid ([EMIM][TFSI]) in the nanopores of a HKUST-1 metal-organic framework. 3D angstrom-level ionic channels of the metal-organic framework (MOF) host were used to restrict electrolyte anions and acted as highways for fast Li+ transport. In addition, lower interfacial resistance between HKUST-1@IL-Li and electrodes was achieved by a wetted contact through open tunnels at the atomic scale. Excellent high thermal stability up to 300 degrees C and electrochemical properties are observed, including ionic conductivities and Li+ transference numbers of 0.68 x 10(-4) S center dot cm(-1) and 0.46, respectively, at 25 degrees C, and 6.85 x 10(-4) S center dot cm(-1) and 0.68, respectively, at 100 degrees C. A stable Li metal plating/stripping process was observed at 100 degrees C, suggesting an effectively suppressed growth of Li dendrites. The as-fabricated LiFePO4/HKUST-1@IL-Li/Li solid-state battery exhibits remarkable performance at high temperature with an initial discharge capacity of 144 mAh center dot g(-1) at 0.5 C and a high capacity retention of 92% after 100 cycles. Thus, the solid electrolyte in this study demonstrates promising applicability in lithium metal batteries with high performance under extreme thermal environmental conditions.

Automated summary

This study addresses the safety challenges in lithium batteries caused by traditional electrolytes at high temperatures. A novel solid electrolyte (HKUST-1@IL-Li) was fabricated by immobilizing ionic liquid in the nanopores of a metal-organic framework. The solid electrolyte demonstrated remarkable thermal stability and ionic conductivities, showing promising applicability in lithium metal batteries under extreme thermal environmental conditions.