Inhibition of lithium dendrites by a LiPON interlayer with Li+ conductive and electron non-conductive dynamic properties based on Li7La3Zr2O12 solid electrolyte

Abstract

The lithium dendrite problem of Li7La3Zr1.4Ta0.6O12 (LLZTO) solid electrolyte restricts the practical application and development of all-solid-state lithium batteries (ASSLBs). Herein, a LiPON interlayer with Li+ conductive and electron non-conductive dynamic properties is constructed at the Li/LLZTO interface. Results show that the electronic conductivity of solid electrolyte after LiPON modification decreased by nearly three orders of magnitude, indicating that it has good ability to hinder electron conduction. The interlayer enhances the wettability between the Li metal anode and LLZTO, resulting in a decrease of battery resistance from 3400 Ω to 700 Ω. The critical current density of the ASSLBs increase from 0.1 mA cm−2 to 1.2 mA cm−2 at room temperature, and the battery cycle number increase from 31 h to over 1000 h. XPS deep etching results show that the LiPON/LLZTO interface has good electrochemical stability. The Kelvin probe force microscope displays a sharp increase in potential within the LiPON interlayer, indicating its successful hindrance of electron conduction to the solid electrolyte. The effective inhibition of lithium dendrites growth is due to LiPON can promote the Li+ transmission from LLZTO solid electrolyte to Li anode, and also hinder the electron conduction to LLZTO to form lithium dendrites.