Li_6.75La₃Zr_1.75Ta_0.25O₁₂-2wt.%Li₃OCl Inorganic Composite Solid Electrolyte And Its Application In Lithium Metal Batteries

Li₇La₃Zr₂O₁₂?LLZO?garnet-type oxide has become a promising inorganic electrolyte for solid-state lithium-ion batteries due to its high ionic conductivity and good chemical stability with the lithium metal.However,the poor wettability of LLZO garnet-type oxide with lithium metal and its incompact structure have impeded their extensive applications in solid-state lithium-ion batteries.Herein,Li_6.75La₃Zr_1.75Ta_0.25O₁₂?LLZTO?particles were embedded in the amorphous Li₃OCl to form an integrated composite electrolyte?LLZTO-2wt.%Li₃OCl?with compact and stable structure at 350 ^oC,which presents high ionic conductivity(2.27×10^-4 S cm^-1),low interfacial resistance and high electrochemical stability?up to 10 V vs.Li/Li⁺?at room temperature.The amorphous Li₃OCl acting as a binder,filler and bridge promotes the formation of an integrated composite electrolyte and continuous ionic conductive network among LLZTO particles.Furthermore,the Li₃OCl with excellent affinity to lithium metal in-situ reacts with the lithium metal to form a stable and dense interfacial layer,which greatly decreases the interfacial resistance between the composite electrolyte and lithium metal?from 1850 to 90?cm²?.The interfacial layer allied compact composite electrolyte also effectively suppresses the lithium dendrite growth during lithium plating-striping.The symmetrical Li/LLZTO-2wt.%Li₃OCl/Li cell can stably cycle 1000 hours without short circuit.The stable specific capacity of solid-state LiFePO₄/LLZTO-2wt.%Li₃OCl/Li battery is as high as 157.5 mAh g^-1 and 85.7 mAh g^-1 at 0.05C and 0.5C,respectively.Combining the garnet-type electrolyte with amorphous Li₃OCl is a promising way to develop the compact garnet-type electrolyte at low temperature for solid-state lithium-ion batteries.A LLZTO-2wt.%Li₃OCl composite solid electrolyte?LC?layer is attached to the surface of Li metal electrode through a glass-fiber-paper?GF?-supported method to form a stable in-situ reaction interfacial layer between Li metal anode and organic liquid electrolyte in Li metal batteries.The Li metal anode modified by GF-LC shows excellent cycling stability in Li metal symmetric battery(over 1100 h stable cycles at 1 mA cm^-2/1 mA h cm^-2 with less corrosion of Li metal anode)and Li-Cu battery(over 300 h cycles at 1 mA cm^-2/1 mA h cm^-2 with coulombic efficiency of99.0%).The superiorly stable and dendrites-free mechanism of GF-LC modified Li metal anode is related with reduced direct contact area and less corrosive side reactions between organic electrolyte and Li metal anode.Based on the excellent stability of GF-LC modified Li metal anode,Li-S battery is assembled to research the effect of GF-LC modified Li metal anode on cycling stability.Compared with Li-S batteries modified by pristine and GF modified Li metal anodes,the GF-LC modified Li-S battery shows better cycling stability and longer cycling life.