Regulation And Performance Research Of Lithium Metal/Electrolyte Interface In All-Solid-State Lithium-air Battery

Lithium-ion batteries in traditional organic systems have the problems of low energy density,lithium dendritic growth in the negative electrode,and flammability of the electrolyte,and can no longer meet the needs of long-range mileage for new energy vehicles.Dendrites pierce the membrane easily,cause short-circuiting,and ignite the electrolyte.There are countless explosions.Because of this,all-solid-state lithium-air batteries have received a great deal of attention because of their high energy density(3500 Wh/kg),and their solid-state electrolytes can inhibit the growth of dendritic crystals and the stability of the mechanism.At present,the research of all-solid-state lithium-air battery is still in the primary stage,which includes the problems of unstable solid interface,large contact resistance,growth of lithium dendrites and low ionic conductivity of air cathode.For the problem of low ionic conductivity of the positive electrode,a high-energy ball milling method was used to synthesize a composite positive electrode material of RuO2/SWCNT/LAGP(1:10:100),which can not only effectively catalyze ORR and OER reactions,but also ensure that the positive electrode has good Electronic and ionic conductivity;For the problems of large interfacial impedance of lithium metal and solid electrolyte and the growth of lithium dendrites,Li1.5Al0.5Ge1.5P3O12(LAGP,～10-4 S cm-1)solid electrolyte sheets have been synthesized in this thesis.The nano-paper was used to polish the side that was in contact with the lithium metal anode,and an ultra-fine interface structure was obtained.For the problem of poor interface contact,the molten lithium was hot-pressed on the side of the LAGP superfine treatment.An ultra-smooth interface structure was obtained through the regulation of the metal lithium and the electrolyte interface.This scheme effectively inhibits the accumulation of lithium dendrites at the "tip" of metallic lithium and the resulting growth of lithium dendrites in the LAGP pores,making the cell at room temperature,current density 400 mA g-1,constant volume 1000 mAh g-1,the cycle life is further increased to 27 cycles(at present,the longest cycle life of all solid state lithium air batteries),which provides a simple,easy,and low-cost method for suppressing the growth of lithium dendrites in solid electrolytes..In addition,we innovated the use of atomic force microscopy(AFM)to in-situ characterize changes in anode morphology and potential of all-solid-state lithium-air batteries.