Newly developed sodium-ion batteries could offer much faster charging speeds, greater energy density and safety improvements compared to conventional lithium-ion batteries – scientists say.
Using sodium ion batteriesan alternative to the lithium-ion batteries found in most current devices, researchers at Tokyo University of Science used a new carbon-based electrolyte to improve the batteries’ energy density and charging speeds.
Scientists have been investigating sodium-ion batteries as an alternative to lithium-ion batteries due to their greater stability and low costbut several bottlenecks and limitations have blocked the advancement of technology.
In a study in December, Chemical Sciencescientists set out to overcome the obstacles.
Limit the risks of lithium-ion batteries
All batteries have an anode and a cathode – the two electrodes that determine how current enters and leaves the device. In lithium-ion batteries, the cathode is mainly made of graphite, as it is an excellent material for storing lithium ions for later discharge.
But sodium ion batteries use hard carbon (HC) — a porous combination of thousands of “turbostractic basic structural units” – a complex crystalline structure that is excellent at storing sodium ions. This is, in theory, a very fast loading material.
As detailed in the new study, small concentrations of HC were combined with aluminum oxide, a chemically inactive material, in a combined electrode. This allowed ions to flow freely into the HC particles. no “traffic” problems.
With the problem overcome, the researchers demonstrated that sodium ions could enter the HC at similar rates to lithium ions entering the graphite in a lithium-ion battery.
The researchers also discovered that the bottleneck of the entire process is the rate at which ions fill the “couples” inside the HC, with “pores” describing the process by which ions form pseudo-metallic clusters within nanoscopic pores along the surface of the HC.
Through careful analysis, researchers discovered that carbon ions sodium require less energy to form these clusters.
The discovery indicates that, under the right conditions, sodium-ion batteries (also called SIBs) can reach faster charging rates than lithium-ion batteries.
“The results also suggest that the Sodium insert is less sensitive to temperaturebased on the consideration of a lower activation energy than that of lithiation”, the study leader told Live Science, Shinichi Komabaprofessor in the Department of Applied Chemistry at Tokyo University of Science.
As the researchers praise in the same magazine, the results could help sodium-ion batteries gain more widespread adoption in applications that require extremely fast charging or discharging speeds.
