Preparation method of silicon-carbon negative electrode material for sodium-ion battery

The invention discloses a preparation method of a silicon-carbon negative electrode material for a sodium-ion battery. The invention aims to improve the performance of anthracite used as a sodium-ion battery negative electrode material so as to meet the actual production requirements of anthracite used as a sodium-ion battery. The method comprises the following steps: 1, mixing anthracite and silicate (potassium silicate or sodium silicate), and putting the mixture into a ball milling tank for ball milling; 2, putting the mixture subjected to ball milling in the step 1 into a constant-temperature magnetic stirrer, heating while stirring, adding dilute acid into the mixture, and then filtering, washing and drying; and 3, drying the powder obtained in the step 2, putting the dried powder into a quartz boat, carrying out high-temperature carbonization in an inert gas environment, and naturally cooling. And 4, adding calcium hydride powder into the powder obtained in the step 3 according to a certain proportion,