DETROIT – The scientific push to make cheap sodium-ion batteries a viable alternative to the packs with lithium cells that go into electric cars and energy storage systems can only be compared to the R&D rush that went into LFP batteries in the past decade or so.
The phosphate cells that don’t use expensive nickel or cobalt slowly fell down in price, leading to proliferation of portable power stations like the Anker Solix series that sell for less than a grand on Amazon. Their energy density also increased, and charging performance in cold weather improved. So much so, that LFP is increasingly the battery chemistry of choice when it comes to mass electric vehicles and energy storage.
Something similar is happening in the field of sodium-ion batteries. The base material is 50 times cheaper than lithium, and so abundant it can be distilled from seawater. The more than a decade of research into creating a viable sodium-ion alternative to lithium in batteries is now starting to bear fruit. The first electric cars and grid-level energy storage systems are coming online, and the two biggest battery makers CATL and BYD are increasingly prioritizing their production, despite the precipitous drop in the price of lithium in the past year or so.
The weakest point of sodium-ion batteries – their energy density – is slowly being addressed, too, with more and more lab-level research seeping through into production lines. The latest case in point is the breakthrough discovery of a sodium vanadium phosphate compound (NaxV₂(PO₄)₃) that a group of scientists from the University of Houston and a number of French universities managed to take from the theoretical to the practical realm.
The vanadium phosphate material increases the theoretical energy density from the current 396 Wh/kg average to 458 Wh/kg, closing in on lithium-ion batteries. What’s more, the use of vanadium allows the cells to remain stable during rapid charging and discharge, while delivering a higher, 3.7 V voltage than the typical cells used now.
According to the researchers, “the continuous voltage change is a key feature” because it makes the battery more energy-efficient without affecting the electrodes’ stability. The team even goes as far as calling this “a game-changer” for the commercialization of the sodium-ion battery chemistry and says that the proprietary process can be applied to other potential electrode materials, too.
