A method for improving the density and conductivity of tantalum-doped garnet-type solid electrolyte

A solid-state electrolyte, garnet-type technology, applied in the field of electrochemical energy storage, can solve the problems of insufficient improvement of electrical conductivity and density, and achieve the advantages of improving cycle stability, inhibiting abnormal grain growth, and improving density. Effect

CN113402271BActive Publication Date: 2022-04-29HARBIN INST OF TECH
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
Publication Date
2022-04-29

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Abstract

The invention discloses a method for improving the density and conductivity of a tantalum-doped garnet-type solid electrolyte, which belongs to the field of electrochemical energy storage. The invention aims to solve the technical problem that the electrical conductivity and density of the existing tantalum-garnet-type solid electrolyte have not been fully improved. The method of the invention includes powder mixing, wet ball milling, drying, pre-sintering, wet ball milling, drying, grinding and sieving, rubber mixing and tabletting, degumming, powder burying and sintering. The present invention by doping La 2 o 3 Nanoparticles to adjust the element ratio of La site and Zr(Ta) site in tantalum-doped garnet-type solid electrolyte LLTZO, and then mediate the mesophase LaTaO 4 The formation of LLTZO can effectively inhibit the abnormal grain growth of LLTZO, and improve the sintering homogeneity of tantalum-doped garnet-type solid electrolyte, and at the same time reduce or eliminate hole defects to improve the density, thereby improving the ion conductivity and improving the cycle of solid-state batteries stability. The method of the invention is simple, the sintering cost is low, and industrialized mass production can be easily realized.
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Description

technical field

[0001] The invention belongs to the field of electrochemical energy storage; In particular, the invention relates to a method for improving the density and conductivity of tantalum doped garnet solid electrolyte. Background technology

[0002] With the rapid development of lithium-ion batteries, higher requirements are put forward for the safety of batteries, and the discovery of solid electrolyte can meet this requirement. Garnet solid electrolyte (LI) 7 La 3 Zr 2 O 12 ）It is one of the most potential electrolytes. However, low conductivity and density are urgent problems to be solved.

[0003] At present, element doping can provide more lithium ion vacancies, stabilize the cubic phase, reduce the sintering temperature and the fluidity of the liquid phase, so as to improve the density and conductivity. Among them, tantalum doping can effectively improve the conductivity of garnet solid electrolyte, as shown in the following documents:

[0004] Document 1: T. Thom...

Examples

Embodiment 1

[0038] A method for improving the density and conductivity of tantalum doped garnet solid electrolyte in this embodiment adopts tantalum doped garnet solid electrolyte as Li 2 CO 3 ，La 2 O 3 ，ZrO 2 And TA 2 O 5 The mixed powder is formed by solid-state sintering, and the sintering process is by adding la 2 O 3 Nanoparticles to mediate mesophase La 2 Zr 2 O 7 (LaTaO 4 ）And then promote the formation of llzto at the grain boundary. This is accomplished through the following steps:

[0039] Step 1: according to Li 6.5 La 3 Zr 1.5 Ta 0.5 O 12 Weigh Li 2 CO 3 、La 2 O 3 ，ZrO 2 And TA 2 O 5 Mix the powder evenly, Li 2 CO 3 Excess 10wt.%, Isopropanol was used as solvent for wet ball milling. The volume ratio of isopropanol to mixed powder was 70ml: 20g, and the grinding ball was ZrO with diameter of 4mm and 6mm 2 Ball, the mass ratio of two kinds of grinding balls is 1:1, the mass ratio of mixed powder to grinding ball is 1:1, the rotating speed is 200rpm, and the milling time is 10h. The...

Embodiment 2

[0046] A method for improving the density and conductivity of tantalum doped garnet solid electrolyte in this embodiment adopts tantalum doped garnet solid electrolyte as Li 2 CO 3 ，La 2 O 3 ，ZrO 2 And TA 2 O 5 The mixed powder is formed by solid-state sintering, and the sintering process is by adding la 2 O 3 Nanoparticles to mediate mesophase La 2 Zr 2 O 7 (LaTaO 4 ）And then promote the formation of llzto at the grain boundary. This is accomplished through the following steps:

[0047] Step 1: according to Li 6.5 La 3 Zr 1.5 Ta 0.5 O 12 Weigh Li 2 CO 3 、La 2 O 3 ，ZrO 2 And TA 2 O 5 Mix the powder evenly, Li 2 CO 3 Excess 10wt.%, La 2 O 3 Excess 5wt.%, Isopropanol was used as solvent for wet ball milling. The volume ratio of isopropanol to mixed powder was 70ml: 20g, and the grinding ball was ZrO with diameter of 4mm and 6mm 2 Ball, the mass ratio of two kinds of grinding balls is 1:1, the mass ratio of mixed powder to grinding ball is 1:1, the rotating speed is 200rpm, and the m...