United States scientists have recently developed the world's first anode-free sodium solid-state battery. This has led to the development of inexpensive, fast-charging, high-capacity batteries for use in electric vehicles and power grids. The research paper was published in the latest issue of the journal Nature Energy.
Lithium-based batteries have become the standard for electric vehicles and mobile devices, but their performance is limited by a number of factors. First, lithium is limited in the earth's crust. In addition, the surge in demand for lithium-ion batteries has led to a rising price for lithium. Sodium is about 1,000 times more abundant in the earth's crust than lithium, and it is also a more environmentally friendly battery material.
Conventional battery construction consists of a cathode and an anode. During charging, the anode stores ions. During discharge, ions flow from the anode through the electrolyte to the current collector (cathode) to power the device and the car. In anodeless batteries, ions are stored directly on the surface of the current collector by electrochemical deposition of alkali metals. This approach not only increases the voltage and energy density of the battery, but also reduces the cost, but also introduces new challenges.
First author Grayson · Dey Schell of the University of California, San Diego in United States, explains that in anode-less batteries, good contact between the electrolyte and the current collector needs to be maintained. This is easy to do with liquid electrolytes because liquids can flow around while solid electrolytes cannot. However, while the liquid electrolyte consumes the active material, it will produce solid electrolyte interface buildup, resulting in reduced battery performance.
To solve this problem, the research team took a different approach and developed a new sodium battery architecture: they used solid aluminum powder with liquid-like fluidity to construct the current collector. During battery assembly, the aluminum powder becomes dense under high pressure, forming a solid current collector while maintaining liquid-like contact with the electrolyte, enabling low-cost, high-efficiency charge-discharge cycles.
The research team believes that the newly developed sodium battery has a stable structure and can be cycled hundreds of times. The removal of the anode and the replacement of lithium with sodium make the production process of the new battery more economical and environmentally friendly. The innovative solid-state design also improves the safety of the battery.