With the gradual trend of electrification in the automotive industry, the technological development of power batteries has also begun to accelerate. Currently, most new energy vehicle models on the market are equipped with lithium-ion power batteries, which are in short supply and high demand, leading to continuously rising manufacturing costs. Due to the limited global lithium mineral resources, the market has been actively exploring alternatives to lithium-ion batteries. Sodium-ion batteries have gained attention in the past two years, especially after 2023, with news about the “boarding” of sodium-ion batteries flooding the industry. So why is sodium-ion battery receiving such attention? What are its advantages and disadvantages compared to lithium-ion batteries? 1. What is a Sodium-ion Battery? In fact, the development of sodium-ion batteries started at the same time as lithium-ion batteries, but due to technological bottlenecks and performance gaps, they have not been widely used. With technological advancements, some of the bottlenecks have been gradually overcome, and the energy density of sodium-ion batteries has been increasing, with breakthroughs in driving range. In addition, the reserves of sodium ore on Earth are much higher than lithium ore, making the cost of manufacturing sodium-ion batteries much lower than lithium-ion batteries, thus making sodium a new power battery technology route.
Sodium-ion batteries are very similar to lithium-ion batteries, both relying on the movement of metal ions within the battery to achieve charging and discharging. They are also both secondary batteries, commonly known as rechargeable batteries, which means they can be used repeatedly. One of the main differences between sodium-ion batteries and lithium-ion batteries is the charge carrier, with the electrode material in sodium-ion batteries being sodium salt. The working principle of sodium-ion batteries and lithium-ion batteries is very similar. During charging, sodium ions are released from the positive electrode active material lattice, raising the positive electrode potential. At the same time, sodium ions further migrate to the surface of the negative electrode in the electrolyte and embed themselves in the negative electrode active material lattice. During this process, electrons flow from the positive electrode to the negative electrode through the external circuit, causing the potential difference between the positive and negative electrodes to increase and charging the sodium-ion battery. During discharging, the migration of sodium ions and electrons is reversed, with sodium ions leaving the negative electrode and re-embedding themselves in the positive electrode active material lattice after passing through the electrolyte. Electrons flow from the negative electrode to the positive electrode through the external circuit, providing energy to the electrical devices connected to the external circuit, completing the battery’s discharging and energy release. 2. Positive electrode material route
Compared to traditional lithium-ion batteries, sodium-ion batteries have an important difference in addition to the difference in electrolyte, which is the difference in the positive electrode material. At present, there are mainly three types: Prussian blue positive electrode, layered oxide positive electrode, and polyanion positive electrode. The Prussian blue positive electrode is a compound composed of sodium and ferricyanide, usually blue, with the characteristics of high voltage and high energy density, simple preparation process, and low cost; the layered oxide positive electrode is composed of sodium and metal oxides such as copper, iron, manganese, and nickel, with high energy density and long cycle life; the polyanion positive electrode materials include sodium iron phosphate and sodium vanadium phosphate, with higher safety and longer life. 2. Advantages and disadvantages of sodium-ion batteries 1. Advantages of sodium-ion batteries
