Inorganic solid electrolyte with surface made of amorphous substance and preparation method thereof

Abstract

The invention provides a preparation method of an inorganic solid electrolyte with a surface made of an amorphous substance. The preparation method comprises the following steps: A) preparing an amorphous substance having the same chemical composition as a solid electrolyte substrate material by a melting-quenching method or a high-energy ball milling method; B) mixing the amorphous substance, a binder and a solvent to obtain composite material slurry; and C) coating the surface of the solid electrolyte substrate material with the composite material slurry, removing the solvent and the binder,and softening the amorphous substance to obtain the inorganic solid electrolyte with the surface made of the amorphous substance.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to an inorganic solid electrolyte whose surface is an amorphous substance and a preparation method thereof. Background technique [0002] Lithium secondary batteries are widely used in daily life with many advantages such as large output power, high energy density, excellent cycle performance, no memory effect and no environmental pollution. The most competitive vehicle power battery. [0003] Current commercial lithium-ion batteries widely use liquid electrolytes, which are characterized by high electrical conductivity and excellent electrochemical performance. However, the liquid electrolyte has a low flash point, which may cause the electrolyte to heat up and spontaneously ignite under abnormal conditions such as high-current discharge, overcharging, and internal short circuit, and even cause safety problems such as explosion. At the same time, from th...

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Problems solved by technology

However, although the lithium dendrite growth phenomenon in batteries due to the uneven deposition and dissolution of lithium can be suppressed by solid electrolytes with high shear modulus, there are still some problems for metallic lithium in full oxide electrolyte-based electrolytes. The application of solid-state lithium batteries poses challenges: 1. The solid-point contact between metal lithium and the electrolyte causes large interface impedance and poor battery dynamics; 2. During charging and discharging, especially at high rates, the volume of metal lithium The expansion and contraction will gradually accumulate stress on the interface, and the electrolyte block will be deformed and broken, which will further deteriorate the contact; 4+ 、 Ge 4+ ) There is a continuous interface reaction between the solid electrolytes that penetrates into the electrolyte body, generating ion-electronic mixed conductive regions and low-conductivity by-products, which destroy the interface contact and the structural strength of the electrolyte body while reducing the conductivity of lithium ions

4. Lithium metal and some electrolytes with low density (such as LLZO) have a spontaneous chemical reaction at the grain boundary to form an electronically conductive phase, causing the battery to short-circuit

[0013] 1. The effect of modifying the interface of crystalline substances is not significant, and its intrinsic polycrystalline boundary and high rigidity determine that it cannot take into account both stability to lithium and good contact, that is, poor compatibility

[0014] 2. In the existing polymer modification, although it is effective for a short time, there are often hidden dangers of lithium dendrites, and the good compatibility of the electrolyte with lithium metal has not really been achieved.

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