New, Safer Lithium-Ion Batteries

Source: Oleksandr Marynchenko - 123RF

Science reports that a new generation of lithium-ion batteries could hold more charge—without catching fire.

Lithium-ion batteries contain three main components: two charge-storing electrodes and a liquid organic electrolyte that separate them. The electrolyte ferries lithium ions back and forth between the electrodes during charging and discharging, but they’re flammable.

In 2016, Samsung recalled the Note 7 after several reports of exploding and burning devices due to a battery defect.

In June 2018, a Boeing 737-700 WestJet flight, from Calgary International Airport (CYYC), Alberta, to Vancouver International Airport (CYVR), British Columbia, with 2 flight crew members, 3 cabin crew members, and 53 passengers on board, was forced to return to the airport following a fire in the cargo hold of the aircraft.

According to a report by the Transportation Safety Board of Canada, the bag belonged to a passenger who “flew frequently for business purposes and was aware of WestJet’s policies” that say e-cigarettes and the lithium-ion batteries associated with them must be in carry-on baggage only, not in checked bags.

The passenger had inadvertently packed two spare lithium-ion batteries for his e-cigarette in a front pocket of his bag before he checked in the bag at the airport, the report states.

Researchers report they’ve redesigned these batteries to work with nonflammable materials. As a bonus, the new batteries might even store more power than current models.

In recent years, researchers have experimented with replacing these organic electrolytes with solid electrolytes or water-based versions that can’t catch fire. But if the operating voltage of these water-based batteries exceeds 1.23 volts (V)—below that of even a 1.5-V AA battery—electrode materials can react with water molecules, splitting them into hydrogen and oxygen gases, often with explosive results.

Yet, when researchers stay below the 1.23-V threshold, they end up with batteries that store far less energy than traditional lithium-ion cells, which operate at about 4 V.

The report adds that if commercialized, the new batteries could help keep drivers of electric vehicles safe even if they wind up in an accident.