Optimization of solid electrolytes (SEs) is of great significance for lithium-based solid state batteries (SSBs). However, insufficient Li ion transport, deficient interfacial compatibility and formation of lithium dendrites lead to poor cycling performance. Based on Li⁺ conductive metal–organic frameworks (LCMOFs), herein a multiscale optimization strategy is put forward to facilitate Li⁺ transport within the MOFs (molecular scale), between the MOFs’ boundaries (nanoscale) and across the SE/electrode interface (microscale) in SSBs. LCMOFs are obtained by binding Li⁺ onto ionogenic chemical groups (–CO₂H, –SO₃H and –OH) in nanoscale dispersed MOFs. Both experimental results and DFT simulations confirm the key role of ionogenic groups for Li⁺ transport. Furthermore, benefiting from the optimized interfaces between LCMOF crystals, SEs with excellent electrochemical properties are obtained, including a high ionic conductivity of 1.06 × 10⁻³ S cm⁻¹ at 25 °C, a wide electrochemical window from 2.0 to 4.5 V, low interfacial resistances and stable Li plating/stripping. The fabricated Li|SE|LiFePO₄ SSB exhibits high and stable charge/discharge capacities under wide operation temperatures ranging from −20 to 60 °C.

中文翻译：

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通过离子导电金属-有机骨架对锂金属电池中锂离子扩散的多尺度优化

固态电解质（SEs）的优化对于锂基固态电池（SSB）具有重要意义。但是，锂离子输运不足，界面相容性不足以及锂枝晶的形成会导致循环性能变差。本文基于Li ⁺导电金属-有机骨架（LCMOF），提出了一种多尺度优化策略，以促进Li ⁺在MOF（分子尺度）内，MOF的边界（纳米尺度）之间以及跨SE /电极界面（微米级）。LCMOF是通过将Li ⁺结合到离子化学基团（–CO ₂ H，–SO ₃H和–OH）在纳米级分散的MOF中。实验结果和DFT模拟都证实了离子基团对于Li ⁺传输的关键作用。此外，得益于LCMOF晶体之间的优化界面，获得了具有优异电化学性能的SE，包括在25°C时具有1.06×10 ^-3 S cm ^-1的高离子电导率，2.0至4.5 V的宽电化学窗口，低界面电阻和稳定的锂电镀/剥离。所制得的Li | SE | LiFePO ₄ SSB在-20至60°C的宽工作温度下显示出高而稳定的充电/放电容量。