The B2B platform for full-electric and plug-in hybrid electric vehicles: Industry News

Researchers from Mississippi State University suggest a completely new recharging method that could greatly reduce the recharging time for electric vehicles. An additional oscillating electric field is used to charge a lithium-ion battery in only a fraction of the time needed when using traditional methods.

Ibrahim Abou Hamad and colleagues from the Mississippi State University have developed a new technique to recharge li-ion batteries based on large-scale molecular dynamics simulations. In the study they propose to apply an oscillating electric field to the anode of a lithium battery to lower the energy barrier for lithium ions to intercalate more quickly into the anode.

"These simulations suggest a new charging method that has the potential to deliver much shorter charging times, as well as the possibility of providing higher power densities," states the team.

The science behind

Hamad explains that the lithium-ion battery-charging process is marked by the intercalation of lithium ions into the anode material. The intercalation is the rate at which the lithium ions can cross the barrier into the graphite anode. While the electric field pushes the lithium ions towards the anode, the rate-limiting step is the process of intercalation.

“Our simulation results show that this charging method offers a great reduction in the average intercalation time for Li+ ions. The oscillating field not only increases the diffusion rate of Li+ ions in the electrolyte but, more importantly, also enhances intercalation by lowering the corresponding overall energy barrier,” the researcher states in the study.

In addition, the researchers showed that the dependence of the intercalation time on the amplitude is exponential. This means that a small increase in amplitude would lead to a large increase of the intercalation speed and thus to potentially very fast charging times.

Potential barriers to the charging revolution

Battery performance is a complicated balance between huge numbers of competing factors. Before we can evaluate what influence the study will actually have on electric vehicles, the findings have to be tested in a real battery. Technology Review, a magazine published by the Massachusetts Institute of Technology, discussed potential drawbacks of the new method. If the oscillating field does improve charging time in real batteries, manufacturers would then have to check its effect on other performance metrics such as the number of charging cycles a battery can withstand and how long it holds its charge. Consequently, should a faster recharge method mean a shorter battery lifespan, then the trade off might not be worth it. Another question could emerge around the energy efficiency. If the amount of electricity it takes to recharge a battery faster would increase with this method it could be maybe less beneficial.