Researchers have developed a new material that could improve the efficiency of sodium batteries.
Developed by an international interdisciplinary team of researchers, including the Canepa Research Laboratory at the University of Houston, the material could improve the energy performance of sodium batteries.
The new material, sodium vanadium phosphate with the chemical formula NaxV2(PO4)3, improves the performance of sodium-ion batteries by increasing the energy density (i.e., the amount of energy stored per kilogram) by more than 15 per cent, the researchers highlight.
The material has a higher energy density of 458 watt-hours per kilogram (Wh/kg) compared to the 396 Wh/kg of older sodium-ion batteries, bringing sodium technology closer to lithium-ion batteries.
Sodium is nearly 50 times cheaper than lithium and can even be extracted from seawater, making it a more sustainable option for large-scale energy storage, says Pieremanuele Canepa, assistant professor in the Robert Welch Department of Electrical and Computer Engineering at the University of Houston and principal investigator at Canepa Labs.
‘Sodium-ion batteries could be cheaper and easier to produce, helping to reduce reliance on lithium and making battery technology more accessible worldwide.’
The researchers also created a battery prototype using the new material, NaxV2(PO4)3, demonstrating significant energy storage efficiency. NaxV2(PO4)3 belongs to the group of ‘Na superionic conductors,’ or NaSICONs, and is designed to allow sodium ions to move smoothly in and out of the battery during charging and discharging, according to the press release.
The material has a unique way of handling sodium that allows it to work as a single-phase system. This means it remains stable when releasing or absorbing sodium ions. The researchers claim that this allows NaSICON to remain stable during charging and discharging while providing a sustained voltage of 3.7 volts (relative to the sodium metal), which is higher than the 3.37 volts found in existing materials.
The researchers also claim that while the difference may seem small, it significantly improves the energy density of the battery, i.e. how much energy it can store. The key to its efficiency is vanadium, which can exist in multiple steady states, allowing it to hold and release more energy.
‘Continuous voltage variation is a key characteristic. It means the battery can run more efficiently without compromising the stability of the electrodes. This is a disruptive change for sodium-ion technology,’ said Canepa.
The researchers claim that the implications of this study are not limited to sodium-ion batteries. The synthetic method used to make NaxV2(PO4)3 could be applied to other materials with similar chemical properties, opening up new possibilities for advanced energy storage technologies. This, in turn, could affect everything from more affordable and sustainable batteries to powering our devices to help us transition to a cleaner energy economy, according to the press release.
The material shows that sodium-ion batteries can meet the high energy demands of modern technology while being cost-effective and environmentally friendly, Canepa said.
