Resolving anodic and cathodic interface-incompatibility in solid-state lithium metal battery via interface infiltration of designed liquid electrolytes

Owing to their interfacial wettability, liquid electrolytes (LEs) are widely used in all-solid-state lithium metal batteries (ASSLMBs) as interface infiltrators. Nevertheless, no single LE compatible with both anode and cathode impedes its practical applications. To alleviate the issue, ethylene carbonate-based reduction-resistant LEs (RRLEs) and acetonitrile-based oxidation-resistant LEs (ORLEs) are designed as anolyte and catholyte infiltrators to meet the different compatibility requirements of the anode and the cathode with Li 1.6 Al 0.4 Mg 0.1 Ge 1.5 (PO 4 ) 3 (LAMGP), respectively. Electrochemical instability of the LAMGP toward Li metal has been improved by infiltrating the interface using the designed anolyte RRLE. A concentrated LiFSI LE dissolved in EC, a reduction-resistant solvent that solidifies at 25 °C produces an ultra-thin in-situ solidified layer that presents superb interface compatibility between Li metal and LAMGP effectively impedes Li dendrite penetration into the solid-state electrolyte (SSE). Furthermore, the layer raises the critical current density to 2.2 mA cm −2 at 25 °C. On the other hand, the incompatibility between the cathode and the SSE is mitigated by infiltrating the interface using designed acetonitrile-based ORLE catholyte. Finally, the Li|LAMGP|LiNi 0.33 Co 0.33 Mn 0.33 O 2 based battery infiltrated by the designed anolyte and catholyte LEs at its corresponding interface achieves a remarkable reversible capacity of 131.3 mA h g −1 and 88.4% capacity retention after 300 cycles. • Anolyte and catholyte LEs infiltrated interfaces are constructed in ASSLMBs. • In-situ formed ultra-thin layer was observed at the anolyte LE infiltrated interface. • The layer raises the LAMGP's critical current density to 2.2 mA cm −2 at 25 °C. • The interface effectively impedes Li dendrite penetration into the solid electrolyte. • The ASSLMBs achieved 88.4% capacity retention and 98.8% efficiency after 300 cycles.