Abstract: Disclosed is a negative electrode material and a preparation method therefor. The negative electrode material is a core-shell structure, and comprises a core layer formed by hard carbon, and a first carbonized layer, a carbon powder layer and a second carbonized layer which are sequentially coated at the outer side of the core layer. Further disclosed are a negative electrode plate prepared by the negative electrode material, and a sodium ion battery. The negative electrode material of the present disclosure can effectively improve the conductivity of a hard carbon material, thereby facilitating improvement of the performance such as initial Coulombic efficiency and cycle life of the sodium ion battery.

Abstract: The disclosure relates to the technical field of batteries, and discloses a cathode material and a preparation method thereof, a cathode plate and an O3-type layered sodium ion battery. The chemical formula of the cathode material is NaM1-x-y-zNixFeyMnzO2, wherein M comprises a first metal element, and the first metal element has at least one f electron orbital. Ni, Fe and Mn elements in the cathode material are elements containing a d electron orbital. By doping the element M, on the one hand, the f electron orbital and the d electron orbitals are mutually entangled, properties of the cathode material are synergistically improved, so that the structure and air stability of the material are improved; and on the other hand, interaction of all elements in the material can be facilitated, so that ions can move away from original positions to generate vacancies, ion diffusion channels of sodium ions are enlarged, and the rate capability of the material is improved.