EV batteries could last much longer thanks to new capacitor with 19-times energy density that scientists created by mistake

A new material structure could revolutionize energy storage by enabling the capacitors in electric vehicles or devices to store energy for much longer, scientists say.

Researchers have developed capacitors from new "heterostructures" with a novel property that reduces the speed at which energy dissipates without affecting their ability to charge quickly.

The new discovery — which the scientists say was unintended and builds off novel electronics work — could be the foundation for better battery life across consumer devices such as laptops or smartphones, as well as more flexibility in grid-scale energy storage. The scientists described their findings in a study published April 18 in the journal Science.

While batteries can store energy for a long period, they take a long time to charge and discharge electricity. This is where capacitors come in — they store electricity in an electric field that can be quickly charged and discharged for rapid access to power as needed. 

Smartphones, for example, generally use power from the battery but get energy from capacitors when power is needed in a short burst — such as for a camera flash. Each smartphone typically has hundreds of capacitors.

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Some capacitors use ferroelectric materials to store energy. These materials are naturally polarized, which can be reversed by applying a voltage. When the polarization is reversed, this remains in the capacitor like ‘memory’, even after the voltage is removed.