Silicon monoxide/silicon/lithium metasilicate composite negative electrode material and preparation method thereof

Abstract

The invention discloses a silicon monoxide / silicon / lithium metasilicate composite negative electrode material. The silicon monoxide / silicon / lithium metasilicate composite negative electrode material comprises a silicon monoxide / silicon / lithium metasilicate composite material and an inorganic matter coating layer. The invention also provides a preparation method of the silicon monoxide / silicon / lithium metasilicate composite negative electrode material. The preparation method comprises the following steps: taking silicon monoxide and an inorganic compound of lithium element, mixing and ball-milling the silicon monoxide and the inorganic compound of the lithium element, sintering the obtained mixture in a protection gas environment, and naturally cooling the sintered mixture to obtain the silicon monoxide / silicon / lithium metasilicate composite material; and mixing and ball-milling the silicon monoxide / silicon / lithium metasilicate composite material and sintering the obtained mixture undera protection gas condition. The preparation method of the silicon monoxide / silicon / lithium metasilicate composite negative electrode material has the advantages of simplicity, safety, low cost, and easiness in operation and industrial production, and the obtained composite negative electrode material has the advantages of high reversible capacity, excellent cycle performances and high initial Coulomb efficiency.

Description

technical field [0001] The invention relates to the technical field of lithium ion battery materials, in particular to a silicon oxide / silicon / lithium metasilicate composite negative electrode material and a preparation method thereof. Background technique [0002] Lithium-ion batteries are widely used in various electronic products and equipment and electric vehicles because of their high specific energy and long cycle life. The current commercial lithium-ion battery anode materials are mainly graphite-based anode materials, whose theoretical capacity is only 372mAh / g, and the actual capacity is between 340-360mAh / g, which cannot meet the design requirements of high specific energy batteries. Therefore, it has become a key research topic in the field of batteries to develop next-generation new anode materials with high specific capacity, good cycle stability and rate performance to achieve widespread use in electronic products and electric vehicles. [0003] In the past te...

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Problems solved by technology

However, these means are very limited in improving the first Coulombic efficiency of SiO

At present, the academic practice is to learn from the method of pre-lithium on Si, pre-lithium on SiO, and advance the irreversible lithium consumption reaction in the first lithium intercalation process of the electrode cycle to the material preparation stage, and realize it by electrochemical pre-lithium. This method is complicated in process, low in efficiency, high in cost, and difficult to realize large-scale production

[0005] At present, it is still in the initial stage of research to solve the problem of low coulombic efficiency of SiO materials for the first time, and there is no very effective method

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