EV batteries cannot be recharged at consistently high rates of power due to a phenomenon that occurs when a cell is stressed known as lithium plating. Nanoscopic needle-like formations called dendrites grow, and over time they can eventually puncture the separator, causing a short circuit in lithium-ion batteries that use conventional, liquid-based electrolytes. StoreDot, an Israeli startup, believes it has the solution: substitute the carbon in the graphite anode with atoms such as silicon that are in the same group on the periodic table. These exhibit similar properties due to one unifying trait – no matter how many protons they have, they all have four electrons available that can each react to form a distinct chemical bond, just like carbon. StoreDot boss Doron Myersdorf spoke to Automotive News Europe Correspondent Christiaan Hetzner about why this helps his cells fully charge in 5 minutes.
Extreme fast charging of EV batteries would eliminate one of the biggest pain points for mass adoption. How have you solved the resulting problem of lithium plating that limits cell longevity and can cause safety concerns?
This is inherently related to the graphite in the anode. Carbon is extremely stable, so charged lithium ions can be neatly stacked in its crystalline lattice structure like books stored on library shelves. But the Nobel Prize-winning scientists that designed this technology didn't necessarily have speed of charging in mind. The disadvantage of carbon is its high electrical resistance, which is what causes the dendrites during extreme fast charging. However, if you replace carbon with silicon, germanium or tin, the anode becomes more conductive, allowing ions to diffuse into the active material far more quickly.