Achieving Higher Critical Current Density in LGPS-Based Lithium Metal Batteries via a Synergistic Interlayer for Physical Inhibition and Chemical Scavenging of Lithium Dendrites

Abstract

Li_10.35Ge_1.35P_1.65S₁₂ (LGPS) electrolyte has garnered attention due to its high ionic conductivity and processability. However, its strong incompatibility with lithium metal hinders its practical application. Conventional interlayer strategy isolates Li from LGPS, avoiding the detrimental side reactions, but lithium dendrite penetration is still a problem. To address the aforementioned challenges, we develop a PVDF-HFP-supported PDOL-based interlayer (PDOL/PVDF-HFP), which stabilizes the LGPS/Li interface by synergistically physically inhibiting and chemically scavenging lithium dendrites. The multifunctional feature of the interlayer comes from the use of a bifunctional initiator, InCl₃. On the one hand, InCl₃ induces the polymerization of DOL, forming a physical separator and protecting lithium from LGPS; on the other hand, in situ reactions between In³⁺/Cl^– and Li form a LiCl/LiF/LiIn hybrid SEI, homogenizing the surface Li⁺ flux and suppressing lithium dendrite formation and penetration. In addition, an unexpected dynamic microdendrite scavenging is realized by virtue of the side reactions of LGPS/Li, which converts the undesirable reaction to be an advantage in our design. Benefiting from the comprehensive advantages of such design, the constructed sulfide-based solid-state batteries achieve a super low interfacial impedance of 5.1 Ω, a high critical current density (CCD) value over 5 mA/cm², and a super long cycling stability over 8000 h. Our synergistic interlayer strategy would open an effective avenue for solving interfacial challenges for practical sulfide-based solid-state batteries.