Sodium-ion battery electrode material pre-SEI film hard carbon material and application thereof

The invention relates to preparation and application of a sodium ion battery electrode material pre-SEI film hard carbon material, which comprises the following steps: adding a lithium salt and a sodium salt into a heated organic solvent while stirring, and continuously stirring until a uniform dispersion liquid without visible particles is obtained; a hard carbon powder material is added into the dispersion liquid, and the pre-SEI hard carbon material is obtained according to the set stirring speed, heating temperature and stirring reaction preset time. And filtering, washing and calcining to remove the residual organic solvent on the surface. The material disclosed by the invention has the characteristics of low investment, simple preparation process flow, easiness in industrial production, high product consistency, easiness in adjustment of the pre-SEI membranization degree of the product and the like. Besides, the optimized negative plate formula and structural design are adopted, so that the sodium ion b