Button type sodium ion battery and preparation method thereof

The invention belongs to the technical field of sodium ion batteries, and discloses a button type sodium ion battery and a preparation method thereof. The invention provides a button type sodium ion battery. The button type sodium ion battery comprises a positive electrode cover, a positive electrode, a diaphragm, a negative electrode sheet, a gasket, a spring sheet and a negative electrode shell, the positive electrode comprises a current collector and a positive plate. The sodium sheet is suitable for glass fibers, the multi-layer diaphragm is added to serve as a diaphragm interlayer, the diffusion speed of sodium ions can be increased by means of high loading capacity and rapid loading of the multi-layer diaphragm, dissolution of organic matter in electrolyte is prevented, and the high reversible capacity of the sodium battery is kept. The button type sodium ion battery prepared by the method has the advantages of good cyclicity, high energy density and the like. The invention further provides a preparatio