The new batteries are based on the electrodes formed from a mixture of iron oxide, manganese and sodium. The last one is a reactive metal with properties very similar to those of lithium, but widely available worldwide and therefore much cheaper to use.
Despite the high costs and limited life, lithium-ion batteries have been powered portable computers, mobile phones and almost any other portable gadgets for years.
Currently, the development of lithium batteries seems to be reaching an end, showing that the technology is beginning to reach its limits.
A good example of this is the difference between the energy required to charge tablets and smartphones and the energy storage demonstrated by current batteries.
However, the increase of the energy density in Li-ion batteries is made in small steps and the price is higher than production costs.
A group of researchers from the University of Tokyo has come up with a daring project. They propose the replacement of the composition of lithium batteries with a combination of less expensive materials, but with similar results.
Shinichi Komaba’s team has developed a Na-ion battery that offers an energy density of 520 mWhr / g, similar to lithium-ion batteries. Unfortunately, the sodium-ion batteries developed by the Japanese researchers are losing their energy storage capacity after just 30 charging cycles, so their use in commercial products is not yet possible.
But a solution could come from Argonne National Laboratory in Chicago, where another version of the sodium battery is being tested.
A team led by a researcher named Chris Johnson has created a new material using layered vanadium pentoxide which is capable maintaining its capacity for 200 charging cycles.
At present, the most accessible lithium-ion batteries can maintain a minimum of 300 charging cycles, without losing significant energy storage capacity.
The transition to the new type of battery could boost the autonomy of these devices without raising the final costs.
Researchers must now focus on finding a way to store more energy without increasing the physical dimensions of the battery.
Lithium-ion and sodium-ion batteries now offer the same capacity, except that the latter are cheaper.