Recent years have seen a lot of wins for electric vehicles, from skyrocketing sales to newer, more efficient designs. One problem that still hasn’t been solved, however, is charging times, with level 2 charging needing as long as ten hours to get a battery to 80 percent. Next to fears of getting stuck on the road far from the nearest charging station, charging times are probably the biggest concern for those thinking of making the switch to electric.
But that may change soon. In the summer of 2023, South Korean researchers at Pohang University of Science and Technology (POSTECH) announced that research into EV battery materials had resulted in a design that could cut charging times to as little as six minutes. Of all the recent advances in EV technology, this could be one that finally tips the balance in favor of cleaner, more sustainable transportation.
Below, take a look at how this discovery came about, how it works, and what it could mean for the future of EVs.
The vast majority of EVs and plug-in hybrid electric vehicles (PHEVs) on the road today use lithium-ion (Li-ion) batteries. Like all batteries, they contain two electrodes, or media through which electricity can be conducted: a positive electrode, called a cathode, which affects range, and a negative electrode, called an anode, which stores and releases the lithium ions that provide electrical energy.
While there are several reasons why it might take longer to charge an EV battery, the most common, assuming the battery pack is new or in good condition, is the anode. Graphite stores fewer lithium ions and releases them much more slowly than alternative EV battery materials, but it’s also the only material currently suitable for the purpose.
That’s why researchers around the world have been working on alternative materials for anodes, but the first to hit a breakthrough is a team led by Professor Won Bae Kim of the Department of Chemical Engineering and the Graduate Institute of Ferrous & Energy Materials Technology at POSTECH. These researchers found a way to synthesize manganese ferrites, a magnetic metal that, when used as an anode, could contain 1.5 times more lithium ions and shorten charging times to as little as six minutes.
Graphite anodes are engineered to be thick and dense to contain all the ions needed to power a typical EV. While this increases storage capacity, it also slows down charging speeds, as lithium ions can’t get into the anode quickly enough, instead collecting on the surface of the anode as lithium metal. Over time, this layer of metal makes charging take longer and longer until, finally, the battery has to be replaced.
The POSTECH team’s major innovation was to synthesize manganese ferrite in nanometer-thick sheets — in other words, stretching the material farther than graphite can go, and thus increasing the surface area, allowing lithium ions to get into the anode far more quickly. What’s more, it means increased battery capacity and life, as the new anode type can be recharged more times than graphite.
As Professor Kim put it, “We have offered a new understanding on how to overcome the electrochemical limitations of conventional anode materials.” What he means is that his team’s breakthrough could save hours of charging time and make visiting a public charging station as fast and effortless as filling your tank with gas.
There’s no denying that Professor Kim’s work is a major breakthrough for EV batteries, and it may well hold the key to efficient, affordable charging in the near future. However, graphite is likely to carry on as the material of choice for anodes due to its wide availability, low cost, and stability. To put it another way, anodes made from synthetic manganese ferrites might be too costly to produce in large numbers to make practical sense for EV manufacturers.
So, for now, the search for super-fast charging materials is still on, as research is conducted into promising technologies like solid-state batteries, silicon anodes, or lithium iron phosphate (LFP) batteries.
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Published December 1, 2023 5:46PM
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