Molten lithium battery negative electrode material, preparation method and all-solid-state lithium battery

Abstract

The invention provides a molten lithium battery negative electrode material, a preparation method and an all-solid-state lithium battery. A small amount of Si3N4 is added into molten Li to adjust the surface tension of the molten Li, and the molten Li-Si-N after reaction can change point contact of lithium and a garnet interface into surface contact, so that the wettability of a garnet electrolyte and metal lithium is improved, the interface impedance of the two is reduced, and a uniform electric field is provided for lithium deposition and stripping processes. After being assembled into a symmetrical battery, the material shows excellent cycling stability (stably cycling for 1500 hours under the current density of 0.2 mA cm <-2 > and stably cycling for 1000 hours under the current density of 0.4 mA cm <-2 >) and relatively high critical current density (1.8 mA cm <-2 >). The first specific discharge capacity of the assembled all-solid-state battery under the current density of 2C reaches up to 145mA h g <-1 >, and the capacity is kept at 97% after 100 cycles under the current density of 1C.

Description

technical field [0001] The invention relates to a molten state lithium battery negative electrode material, a preparation method and an all-solid lithium battery, belonging to the technical field of all-solid lithium batteries. Background technique [0002] Since the commercialization of the first rechargeable lithium-ion battery by Sony Corporation of Japan in the 1990s, scholars around the world have started a research boom on lithium-ion batteries. Recently, lithium-ion batteries have begun to be used in the field of electric vehicles, but traditional lithium-ion batteries have limited their development in the field of electric vehicles due to low energy density and safety issues caused by flammable electrolytes. The solid-state electrolyte in all-solid-state batteries has good compatibility with lithium metal, and metal lithium, as the "ultimate" anode material of lithium batteries, has an ultra-high theoretical specific capacity (3860mA h g -1 ), extremely low electroc...

AI Technical Summary

Problems solved by technology

These buffer layers can react with lithium metal in situ, so that the interface changes from lithium-phobic to lithium-friendly, and realizes the close contact between metal lithium and garnet electrolyte, but the lithium ion conductivity of the polymer film at room temperature is too poor to be practical middle application

Although inorganic thin films can achieve low interfacial impedance at room temperature, they mainly rely on technical equipment such as atomic layer deposition, chemical vapor deposition, and electron beam thermal evaporation. The manufacturing cost is high and it is difficult to scale up.

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