Magnesium lithium silicate pre-lithiated silicon monoxide negative electrode material as well as preparation method and application thereof

Abstract

The invention discloses a preparation method of a magnesium lithium silicate pre-lithiated silicon monoxide negative electrode material, which comprises the following steps: (1) proportioning: obtaining silicon monoxide negative powder which is silicon monoxide powder without disproportionation treatment; preparing lithium oxide powder, wherein the lithium oxide powder is analytically pure and anhydrous lithium oxide powder; preparing magnesium oxide powder, wherein the magnesium oxide powder is analytically pure; (2) mixing: adding the silicon monoxide powder, the lithium oxide powder and themagnesium oxide powder into a mixer according to a certain proportion, and stirring and mixing at normal temperature to obtain uniform mixed powder A; (3) heat treatment: carrying out heat treatmentreaction on the mixed powder A in the step (2) under inert gas to obtain an intermediate product B; and (4) CVD carbon coating: carrying out carbon coating on the intermediate product B obtained in the step (3) under carbon source gas through a chemical vapor deposition method, wherein the prepared product has relatively high initial coulombic efficiency and good cycling stability.

Description

technical field [0001] The invention relates to the technical field of battery negative electrode materials, in particular to a lithium magnesium silicate pre-lithiated silicon oxide negative electrode material and a preparation method and application thereof. Background technique [0002] At present, lithium-ion batteries (LIBs) have been widely used in the field of power energy. Silicon-based materials have extremely high lithium storage capacity and are considered to be the most promising materials to replace graphite negative electrodes or other carbon negative electrodes. However, in the process of deintercalating lithium, it will lead to large volume expansion of silicon-based negative electrodes, and at the same time, it is easy to form SEI film and grow repeatedly, which will also cause a large loss of active lithium in the first charge-discharge cycle, resulting in irreversible capacity and poor cycle performance. . Among silicon-based materials, SiO has a smaller ...

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Problems solved by technology

However, in the process of deintercalating lithium, it will lead to large volume expansion of silicon-based negative electrodes, and at the same time, it is easy to form SEI film and grow repeatedly, which will also cause a large loss of active lithium in the first charge-discharge cycle, resulting in irreversible capacity and poor cycle performance.

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