Positive electrode composite material of lithium ion battery and all-solid-state battery containing the same

Abstract

The invention discloses a positive electrode composite material of a lithium ion battery. The specific preparation method of the material is as follows: step 1: weighing an appropriate amount of solidelectrolyte and dissolving into an organic solvent, adding an appropriate amount of positive electrode material to the above solution, stirring uniformly in a high-speed dispersion machine, then putting into a vacuum drying oven and drying till the solvent is volatilized completely; and step 2: calcining the obtained solid powder in an atmosphere of an inert gas for a certain time, and cooling with a furnace to obtain the positive electrode material having a core-shell structure. The positive electrode composite material prepared by the invention is provided with the core-shell structure, a positive electrode active material is taken as a core, and the solid electrolyte coated on a surface of the positive electrode active material is a shell layer; with such a core-shell structure, the direct contact between the positive electrode active material and the solid electrolyte can be reduced, and thus the interface problem between a positive electrode and the solid electrolyte is improved;and in addition, the solid electrolyte of the shell layer can further reinforce the ionic conductivity of the material.

Description

technical field [0001] The invention belongs to the field of lithium-ion battery preparation, and relates to a lithium-ion battery cathode composite material and an all-solid-state battery containing the cathode composite material. Background technique [0002] At present, commercial lithium batteries use organic liquid electrolytes. The electrolyte and electrode materials are prone to side reactions during charging and discharging, resulting in irreversible decline in battery capacity. At the same time, during the long-term service of the battery, the organic liquid electrolyte will volatilize and dry up. , leakage and other phenomena will affect the battery life. On the other hand, traditional lithium batteries cannot use metal lithium with high energy density as the negative electrode material. During the battery cycle, due to factors such as the surface current density of metal lithium and the uneven distribution of lithium ions, the repeated dissolution and deposition o...

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Problems solved by technology

[0004] The object of the present invention is to provide a lithium-ion battery positive electrode composite material and an all-solid-state battery containing the positive electrode composite material. The positive electrode composite material has a core-shell structure, the positive electrode active material is the core, and the solid electrolyte coated on its surface is the shell Layer, this core-shell structure can reduce the direct contact between the positive electrode active material and the solid electrolyte, thereby improving the interface problem between the positive electrode and the solid electrolyte. In addition, the solid electrolyte of the shell layer can also enhance the ionic conductivity of the material and solve the problem of Solve the problems of low ion conductivity of existing solid electrolytes, high interfacial impedance between solid electrolytes / electrodes, poor interfacial compatibility, and high cost of battery preparation at this stage

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