Lithium-ion battery composite positive electrode as well as preparation method and application thereof

Abstract

The invention discloses a lithium-ion battery composite positive electrode as well as a preparation method and an application thereof. The composite positive electrode consists of a three-dimensional skeleton structure and inorganic solid electrolyte, wherein the three-dimensional skeleton structure is formed by connecting positive active substance particles, and the inorganic solid electrolyte is filled in the gaps of the skeleton; the positive active substance is one of lithium cobaltate, lithium manganate, lithium iron phosphate or nickel cobalt manganese ternary material; the inorganic solid electrolyte is at least one of lithium borate, lithium metaborate and lithium fluoride. The preparation method comprises the following steps of: respectively pressing the positive active substance and the inorganic solid electrolyte into green-ware, the laminating the inorganic solid electrolyte green-ware above the positive active substance green-ware, and further sintering the inorganic solid electrolyte green-ware and the positive active substance green-ware to obtain a lithium-ion battery composite positive electrode with high performance. The composite positive electrode only consists of the positive active substance and the inorganic solid electrolyte, no conductive agent or bond is added, and good mass specific capacity, good area specific capacity and good cycling performance can be achieved. The lithium-ion battery composite positive electrode can be used for preparing a liquid electrolyte lithium ion battery and a full-solid lithium ion battery.

Description

technical field [0001] The invention relates to a lithium-ion battery composite positive electrode, a preparation method and application thereof. Background technique [0002] Lithium-ion batteries have the advantages of high energy density, long cycle life, and no memory performance. As commercial energy storage devices, they are widely used in daily life and production. With the advancement of science and technology, people's demand for high-efficiency energy storage equipment is gradually increasing, and safety issues have become the main challenge for lithium-ion batteries in new demands and applications in new fields. [0003] The safety problem of lithium-ion batteries is mainly due to the large amount of flammable organic solvents in liquid electrolytes. All-solid-state lithium-ion batteries use solid-state electrolytes instead of commercial liquid organic electrolytes, which can fundamentally solve the safety problem of lithium-ion batteries. The lithium ion conduc...

AI Technical Summary

Problems solved by technology

The softening temperature of sulfur-based electrolytes is low, and the composite structure is easy to prepare, but it is sensitive to moisture in the air, which brings many problems to preparation, testing and application

In addition, the interface between the chalcogenide electrolyte and some positive electrode materials is unstable, and the positive electrode material needs to be coated with oxides before use, and the process is complicated.

The reported oxide electrolyte system composite positive electrode is generally prepared by spark plasma sintering (SPS) technology, without the use of industrial production

The mass fraction of the electrolyte in the composite positive electrode structure exceeds 30%, and conductive agents such as conductive carbon black need to be added, the mass fraction of the positive active material is low, and the energy density is low

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