MOF-derived ionic conductor enhancing polymer electrolytes with superior electrochemical performances for all solid lithium metal batteries

All solid lithium metal batteries (ASLMBs) are expected to be used for safer energy storage because they are more stable than liquid batteries. However, ASLMBs is limited in practical applications, which is largely due to the poor electrochemical performance of solid electrolytes (SE) and the slow Li⁺ transport at the interface. In order to overcome these problems, we report a unique nanoporous structure based on a metal-organic framework (MOF), in which Li-containing liquid-state electrolytes (IEs) are immersed into the UIO-66 framework to obtain UIO/IEs. When these fillers are added into PEO matrix, the composite electrolyte (PUIE) has many functions, including high ion conductivity (1.47 × 10⁻⁴ S cm⁻¹ at 30 °C), wide electrochemical window (5.2 V) and high Li⁺ transference number (0.47), and good compatibility with Li metal and electrodes. The initial discharge capacity of ASLMBs based on PUIE solid electrolyte is 140.2 mA h g⁻¹, which can still be maintained after 135.4 mA h g⁻¹ cycles after 100 cycles. This work provides a new strategy for preparing ASLMBs, in addition to specific UIO and IEs, it can also explore the application of other kinds of MOF and IEs in ASLMBs system.