Lithium ion battery anode material and preparation method thereof, and lithium ion battery

Abstract

The invention discloses a lithium ion battery anode material and a preparation method thereof, and a lithium ion battery. The preparation method comprises the following steps: (1) mixing aluminum and silicon (II) oxide to obtain a mixture, wherein the mass of silicon (II) oxide is greater than that of aluminum; and (2) firing the mixture under an inert atmosphere or vacuum condition at the temperature of 900-1150 DEG C for 2-12h to obtain the lithium ion battery anode material. According to the preparation method, the raw material aluminum is added in the raw material silicon (II) oxide, due to reaction of the raw material aluminum and silicon (II) oxide, the content of active oxygen in the anode material obtained finally is reduced, and the prepared anode material further comprises aluminum oxide. The content of the active oxygen in the anode material is reduced, the charge-discharge first-time efficiency of the anode material is greatly improved, the specific capacity of the anode material is greatly increased; meanwhile, aluminum oxide in the anode material can be used for relieving the volume expansion of silicon in the anode material, so that the volume effect of the whole anode material is reduced.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to a lithium ion battery negative electrode material, a preparation method thereof, and a lithium ion battery. Background technique [0002] With the rapid development of electronic equipment, the requirements for miniaturization, multi-functionalization and high performance of batteries are constantly increasing. In addition, the capacity of the current commercial negative electrode material graphite is close to 372mAh / g. In order to seek a higher specific energy For negative electrode materials with higher capacity, people are turning their attention to metals that can electrochemically alloy with lithium, such as silicon, tin, and aluminum with higher specific capacity. The theoretical specific capacity of lithium intercalation and desorption of this type of negative electrode material is much greater than that of graphite, and the theoretical lithium in...

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Problems solved by technology

However, it undergoes serious volume expansion and contraction during the process of intercalation and delithiation, and the volume expansion rate is >300%, which causes the powdering and shedding of the material during the charge and discharge process, resulting in the decline of cycle performance.

[0003] In order to improve its cycle performance, the current preparation method is to disperse silicon-based materials into other inactive materials to form a uniform composite material. The inactive material is amorphous carbon, which contains carbon obtained by high-temperature carbonization of organic matter. The amorphous carbon, such as the carbon in the nano-carbon-silicon composite material disclosed in CN1903793, although the inactive material has greatly improved the cycle performance of the material, but due to the high specific surface area of ​​the amorphous carbon, the formation of SEI film, resulting in severe lithium consumption and high irreversible capacity for the first time

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