It is understood that sodium-ion battery is a secondary battery (rechargeable battery) with a similar working principle to lithium-ion battery. The positive and negative electrodes are composed of two different sodium ion embedded compounds. During charging, Na+ is extracted from the positive electrode and embedded in the negative electrode through the electrolyte. At the same time, the compensation charge of the electrons is supplied to the negative electrode through the external circuit to ensure the charge balance of the positive and negative electrodes. During discharge, the opposite is true. Na+ is extracted from the negative electrode and embedded in the positive electrode through the electrolyte. Under normal charging and discharging conditions, the embedding and extraction of sodium ions between the positive and negative electrodes does not destroy the basic chemical structure of the electrode material. From the perspective of charge and discharge reversibility, the sodium-ion battery reaction is an ideal reversible reaction.

According to the data, there are many technical routes for sodium-ion batteries, and there is no clear technical route at present. This has affected the large-scale mass production process to a certain extent. Although the mainstream technical route has not yet been determined, the products basically cannot avoid the three major technical routes of sodium-electric positive electrode materials: layered oxides, polyanion compounds, and Prussian blue (white), and the negative electrode materials are mainly hard carbon and soft carbon. Due to the large differences in performance and cost of different technical routes, there are still disputes in the industry. Among them, polyanion compounds have the highest voice.

In recent years, relevant companies have achieved remarkable results in the research of sodium-ion batteries, especially in the proposal and experimental verification of layered oxide configuration prediction methods, which provides theoretical guidance for the design and preparation of low-cost, high-performance layered oxide positive electrode materials for sodium-ion batteries.