LATP composite positive plate with low interface internal resistance, preparation method and all-solid-state lithium ion battery

A technology of composite positive electrode and positive electrode sheet, applied in the direction of positive electrode, battery electrode, secondary battery, etc., can solve the problem of affecting the electrochemical performance and cycle life of solid lithium battery, irreversible decomposition of inorganic solid electrolyte, reducing solid interface layer resistance, etc. The problem is to shorten the sintering time, improve the electrochemical performance and cycle life, and reduce the sintering temperature.

CN114628775APending Publication Date: 2022-06-14WANXIANG 123 CO LTD
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Patent Information

Authority / Receiving Office
CN · China
Current Assignee / Owner
Publication Date
2022-06-14

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Abstract

The invention relates to the technical field of solid-state lithium ion batteries, and discloses an LATP composite positive plate with low interface internal resistance, a preparation method and an all-solid-state lithium ion battery. Firstly, the LATP composite solid electrolyte is prepared through a co-sintering method, the sintering temperature is reduced, and the sintering time is shortened; then, the surface of the composite solid electrolyte is uniformly coated with an organic polymer electrolyte polyethylene oxide (PEO), so that on one hand, the solid-solid interface stress is buffered, the interface impedance is reduced, the lithium ion transmission capability is improved, meanwhile, the LATP is protected from being influenced by a metal lithium negative electrode, and the performance of the solid lithium battery can be greatly improved; comprise discharge capacity, rate discharge and cycle life.
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Description

technical field

[0001] The invention relates to the technical field of solid-state lithium ion batteries, in particular to a LATP composite positive electrode sheet with low interface internal resistance, a preparation method and an all-solid-state lithium ion battery. Background technique

[0002] All-solid-state lithium batteries (ASLBs) are considered as one of the most promising alternatives for next-generation batteries, and their electrochemical performance is largely determined by the performance of solid electrolytes, which are mainly divided into two categories: polymer solid electrolytes and inorganic solid electrolytes. solid electrolyte. Inorganic ceramic solid electrolytes have high mechanical strength, can prevent the formation and growth of lithium dendrites, and have high temperature stability, which has become a hot research topic recently. However, the large-scale application of LATP still faces two technical difficulties: one is the poor point contact bet...

Examples

preparation example Construction

[0039] A method for preparing the LATP composite positive electrode sheet with low interfacial internal resistance is characterized in that, comprising the following steps: a. preparing LATP composite solid electrolyte

[0040] (1) LiNO 3 , Al(NO 3 ) 3 ·9H 2 O and NH 4 H 2 PO 4 Add to the solvent and mix well until completely dissolved;

[0041] (2) adding a citric acid solution with a mass fraction of 10 to 15%, the molar ratio of the citric acid to the metal element in the solution is 1:1 to 1.5, then adding titanium lactate to the mixed solution, at 70 to 80 ° C Stir for 10-20 hours to obtain a viscous liquid;

[0042] (3) calcining the viscous liquid obtained in step (2) at 200-250° C. for 10-30 minutes, and then calcining at 300-350° C. for 2-3 hours to obtain a solid material;

[0043] (4) the solid material, Li obtained in step (3) 4 SiO 4 Mixing with the positive active material in a mass ratio of 25-30:0.5-1.0:25-30, ball milling for 15-20 minutes to obtain ...

Embodiment 1

[0054] A LATP composite positive electrode sheet with low interfacial internal resistance, comprising a positive electrode sheet and a composite solid electrolyte, the positive electrode sheet includes a positive electrode active material and a conductive agent, a positive electrode active material is added to the composite solid electrolyte, and the positive electrode sheet is placed in the On one side of the composite solid electrolyte, the composite solid electrolyte is a PEO-coated LATP composite solid electrolyte.

[0055] The mass ratio of the positive electrode sheet to the composite solid electrolyte is 1.2:2, and in the positive electrode sheet, the mass ratio of the positive electrode active material to the conductive agent is 20:1; the positive electrode active material is lithium iron phosphate; the conductive agent For conductive carbon black.

[0056] A method for preparing the LATP composite positive electrode sheet with low interfacial internal resistance is ch...

Embodiment 2

[0072] A LATP composite positive electrode sheet with low interfacial internal resistance, comprising a positive electrode sheet and a composite solid electrolyte, the positive electrode sheet includes a positive electrode active material and a conductive agent, a positive electrode active material is added to the composite solid electrolyte, and the positive electrode sheet is placed in the On one side of the composite solid electrolyte, the composite solid electrolyte is a PEO-coated LATP composite solid electrolyte.

[0073] The mass ratio of the positive electrode sheet to the composite solid electrolyte is 1:2, and in the positive electrode sheet, the mass ratio of the positive electrode active material to the conductive agent is 15:1; the positive electrode active material is lithium manganate; the conductive agent For conductive graphite.

[0074] A method for preparing the LATP composite positive electrode sheet with low interfacial internal resistance is characterized...