A 3D Cross‐Linking Lithiophilic and Electronically Insulating Interfacial Engineering for Garnet‐Type Solid‐State Lithium Batteries. (25th October 2020) - Ruan, Yadong
Abstract: 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 Li7 La3 Zr2 O12 (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 Ω cm 2 ) and high critical current densities (CCDs) in the time‐constant mode, 1.8 mA cm −2 at 25 °C and 3.6 mA cm −2 at 60 °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 ≈0.5 mAh cm −2 at 25 °C and 1.2 mAh cm −2 at 60 °C. Moreover, the safety‐enhanced hybrid SSBs matched with LiFePO4 and LiNi0.6 Co0.2 Mn0.2 O2 deliver a remarkable rate and cycling performances, validating the feasibility of this interfacial engineering in various SSB systems. Abstract : Acid‐salt interfacial engineering converts the surface of garnet solid electrolytes into a 3D cross‐linking lithiophilic and electronically insulating layer, which facilitates even contact and addresses the dendrite dilemmas. Superb electrochemical performances are achieved including low interfacial resistance, high critical current density, improved prolonged cycling stability, and great compatibility with various cathodes.