All-solid-state sodium batteries have abundant sodium resources and extremely high energy density, and have broad application prospects. All-solid-state sodium batteries have attracted extensive attention due to their good safety, non-flammability, good thermal stability, and low price, and have great potential in large-scale energy storage systems. However, the realization of practical applications of ASSBs still faces great challenges, such as the lack of various solid electrolytes (SEs), low ionic conductivity, high charge transfer resistance, interfacial problems of SEs, and the growth of Na dendrites in ASSBs, the metal Na The application can increase the energy density, and the solid electrolyte can also inhibit the growth of dendrites.
The development of electrolytes has always been the most important factor restricting the development of all-solid-state batteries. High-performance SEs working at room temperature should possess high chemical stability, high ionic conductivity, good mechanical properties, interfacial compatibility, etc. There are three types of solid electrolytes, including solid polymer electrolytes (SPE), inorganic solid electrolytes (ISE), and their composites.
The most widely studied are oxides, sulfides, and borohydrides. The cathode/electrolyte and anode/electrolyte interfaces of ASSBs suffer from insufficient interfacial contact due to mechanically rigid contacts. Furthermore, the formation of sodium dendrites needs to be addressed in ASSB. Rare metals are not used, and the popularity of the new energy vehicle market has led to a rapid increase in the demand for power batteries. As the key raw materials of power batteries, nickel, manganese, cobalt, lithium and other resources are naturally highly sought after, and their prices are also rising. Especially for China, driven by strong demand for new energy vehicles, the price of power battery raw materials has risen rapidly, especially battery-grade lithium carbonate. At the beginning of 2021, its price will be only 50,000 yuan/ton, and by December 2022, the price will increase by a relatively large amount. The price of rare metal battery materials has soared, making batteries more and more expensive, the product profits of new energy vehicle companies have dropped sharply, and subsidies for new energy vehicles have declined.
Compared with lithium batteries, sodium-ion batteries have the advantages of abundant raw material resources, low cost, environmental friendliness, good high and low temperature performance, and high safety. In terms of resources, the underground reserves of sodium rank sixth and are widely distributed. Salt lakes and seawater contain sodium. The development of sodium-ion batteries can effectively reduce the dependence on imported lithium resources.
