Safe LAGP-based all solid-state Li metal batteries with plastic super-conductive interlayer enabled by in-situ solidification

Safe and high-energy-density all solid-state lithium metal batteries (ASSLMBs) are great in demand for future electrical vehicle and grid energy storage. The compatibility of electrode-electrolyte interface is a critical factor influencing the electrochemical performance of ASSLMBs. Herein, we propose a plastic super-conductive carrier to deter untoward reaction between Li anode and Li_1.5Al_0.5Ge_1.5(PO₄)₃ (LAGP) electrolyte by in-situ solidifying succinonitrile-based plastic interlayer with Li_6.4La₃Zr₂Al_0.24O₁₂ (LLZAO) nanowires (l-SN). The method of in-situ solidification promises the low interfacial resistance. The l-SN interlayer can not only act as a physical obstacle to isolate LAGP pellet from Li metal, but also provide three-dimensional ion channels to regulate the transfer of Li ions, delivering an uniform Li ion distribution for dendrite-free Li deposition. The Li|l-SN|LAGP|l-SN|Li symmetric cell can stably cycle for 240 h without short circuit at room temperature (R.T). This approach enables a high specific capacity of 152.5 mAh g⁻¹ at 0.1C for Li|l-SN|LAGP|l-SN|LiFePO₄ cells at R.T. Furthermore, the integrated ASSLMBs show excellent cyclic stability at 40 °C with an initial discharge capacity of 168.4 mAh g⁻¹ at 0.5C and retention of 93.17% after 100 cycles. The super-ionic property at the interface makes excellent rate performance of ASSLMBs at 40 °C. This strategy is facile and efficient in promising safe and outstanding ASSLMBs and also has some referential values for other unstable electrolyte interface beyond LAGP.