Researchers from the Swiss Federal Laboratories for Materials Science and Technology, Empa and the University of Geneva (UNIGE) have developed a new prototype of a solid sodium battery with better performance and improved safety.

The new sodium based battery prototype, which is said to be all solid state, is designed to store more energy while providing high reliability.

Developed using sodium, which is a cheap alternative to lithium, the battery has been designed to meet the growing demand for batteries with safety demand unlike lithium-ions which consists of a flammable liquid.

According to the researchers, the use of solid sodium instead of a liquid electrolyte in the battery enables the use of a metal anode by blocking the formation of dendrites. This process allows storing more energy while guaranteeing safety.

In order to allow the sodium ions to circulate freely, the battery uses closo-borane as solid ionic conductor.

The inorganic conductor, closo-borane can eliminate the firing risk while recharging the battery, the researchers said.

In order to establish close contact between the battery’s three layers, the team dissolved a part of the electrolyte in a solvent and then added the sodium chromium oxide powder.

The researchers said: “Once the solvent had evaporated, they stacked the cathode powder composite with the electrolyte and anode, compressing the various layers to form the battery.”

During testing, the battery’s electrolytes could withstand 3 volts unlike many other solid electrolytes which got damaged at the same voltage.

Following testing for over 250 charge and discharge cycles, the battery retained 85% of its original energy capacity.

The researchers said that experiments are still ongoing to commercialize the battery solution.

Image: The solid sodium battery’s composition. Photo: © Empa/ University of Geneva.