Negative electrode material and preparation method thereof, negative electrode plate and secondary battery

Abstract

The invention provides a negative electrode material and a preparation method thereof, a negative electrode plate and a secondary battery. The negative electrode material contains an Si element, an O element, an M1 element and an M2 element, the M1 element contains Ca and / or Ba, and the M2 element is selected from electronegativity lt; 1.8 is one or more of metal elements; and carrying out particle size grading on the negative electrode material to obtain a negative electrode material A and a negative electrode material B, and when the ratio of the particle size D50 (A) of the negative electrode material A to the particle size D50 (B) of the negative electrode material B is greater than or equal to 2, the mass content of the element M1 and the mass content of the element M2 meet a certain relational expression. When the negative electrode material is applied to the secondary battery, the capacity and the cycle performance of the battery can be remarkably improved, the expansion of the material can be effectively inhibited, and the safety of the battery is improved.

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