A kind of lithium-ion battery composite negative electrode material and preparation method thereof

Abstract

The invention discloses a composite cathode material for lithium ion batteries and a method for preparing the composite cathode material. The composite cathode material for the lithium ion batteries comprises Li<4>Ti<5>O<12> and lithium ion conductors Li<1.3>Al<0.3>Ti<1.7>(PO<4>)<3>. A mass percentage ratio of the Li<4>Ti<5>O<12> to the Li<1.3>Al<0.3>Ti<1.7>(PO<4>)<3> is 0.88-0.98:0.12-0.02; the Li<4>Ti<5>O<12> and the Li<1.3>Al<0.3>Ti<1.7>(PO<4>)<3> are simultaneously generated under identical reaction conditions. The method includes preparing cathode materials and solid electrolyte mixtures under the identical conditions by the aid of special chemical processes. The composite cathode material and the method have the advantages that solid electrolyte is uniformly dispersed in active materials, the cathode materials and the solid electrolyte mixtures are prepared under the identical conditions and are good in structural and electrochemical consistency, and accordingly electrodes are superior in electrochemical performance; the problem that existing electrode materials and solid electrolyte needs to be mechanically mixed with one another for a long time can be solved, and accordingly the electrode manufacturing time can be greatly shortened.

Description

technical field [0001] The invention belongs to the field of lithium batteries, in particular to a lithium ion battery composite negative electrode material and a preparation method thereof. Background technique [0002] Li 4 Ti 5 o 12 The intercalation and extraction of lithium ions have little effect on the structure of the material during the charge and discharge process, which is called a zero-strain material and is an ideal intercalation electrode. Li 4 Ti 5 o 12 As a lithium-ion battery anode material, its lithium intercalation and extraction potential is 1.55V, which can be compared with LiMn 2 o 4 、LiCoO 2 Lithium-ion batteries with a working voltage of 2.4V composed of 4V-level cathode materials have broad commercial prospects in energy storage and power lithium-ion batteries. [0003] Currently working on Li 4 Ti 5 o 12 Carbon black needs to be added to the electrode to improve the electronic conductivity of the material, but Li 4 Ti 5 o 12 The ionic...

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Problems solved by technology

[0003] Currently working on Li 4 Ti 5 o 12 Carbon black needs to be added to the electrode to improve the electronic conductivity of the material, but Li 4 Ti 5 o 12 The ionic conductivity and electronic conductivity of the electrode are both low, and the ionic conductivity of the electrode is still low, which affects the electrochemical performance of the material to a certain extent.

[0004] Therefore, when making solid batteries, it is often necessary to add lithium ion conductors to the electrode materials, but usually the ready-made electrode materials are mixed with lithium ion conductors. Due to mechanical mixing, the mixing uniformity is not good, which affects to a certain extent. Electrochemical properties of materials