A 3D Cross-Linking Lithiophilic and Electronically Insulating Interfacial Engineering for Garnet-Type Solid-State Lithium Batteries

Solid-state batteries (SSBs) promise high energy density and strong safety due to using nonflammable solid-state electrolytes (SSEs) and high-capacity Li metal anode. Ta-substituted Li7La3Zr2O12 (LLZT) SSE possesses superior ionic conductivity and stability with Li metal, yet the interfacial compatibility and lithium dendrite hazards still hinder its applications. Herein, an interfacial engineering is demonstrated by facile acid-salt (AS) treatment on LLZT, constructing a 3D cross-linking LiF-LiCl (CF) network. Such structure facilitates Li wetting via capillary permeation. Notably, CF as electronically insulting phases block the electrons through the interface and ulteriorly suppress the dendrite formation. The assembled Li symmetric cell exhibited a low interfacial impedance (11.6 omega cm(2)) and high critical current densities (CCDs) in the time-constant mode, 1.8 mA cm(-2) at 25 degrees C and 3.6 mA cm(-2) at 60 degrees C, respectively. Meanwhile, by exploring the capacity-constant mode of CCD measurement, the concept of critical areal capacity (CAC) is first proposed, obtaining its values of approximate to 0.5 mAh cm(-2) at 25 degrees C and 1.2 mAh cm(-2) at 60 degrees C. Moreover, the safety-enhanced hybrid SSBs matched with LiFePO4 and LiNi0.6Co0.2Mn0.2O2 deliver a remarkable rate and cycling performances, validating the feasibility of this interfacial engineering in various SSB systems.

Automated summary

In this study, an interfacial engineering approach was demonstrated on LLZT by acid-salt treatment, resulting in the construction of a 3D cross-linking LiF-LiCl network that facilitates Li wetting and suppresses lithium dendrite formation. This method successfully reduced interfacial impedance and increased critical current density, while introducing the concept of critical areal capacity (CAC) in CCD measurement. The safety-enhanced hybrid SSBs showed remarkable rate and cycling performances, confirming the feasibility of this interfacial engineering in various SSB systems.