Prototype promises better lithium batteries

Electric vehicles run on rechargeable batteries, but the lifespan of a full battery and the distance they can travel in a single charge needs to improve if they are ever to compete with their petrol-based equivalents.

Lithium batteries — the best material for storing charge — become unsafe when deposits of the liquid electrolyte form 'dentrites' on the electrodes causing the battery to short circuit. Moreover, the liquid electrolyte can become hot and pressurized, causing it to explode.

Now, a team of engineers, which includes Moroccan material scientist Abdelmaula Aboulaich who now works with the MANAGEM Group in Marrakech, built a lithium battery with an electrolyte made from a solid block copolymer of polystyrene with lithium salt grafts. This prototype outperforms its lithium rivals, according to their report in Nature Materials¹.

Since the electrolyte is solid, it stifles the growth of dendrites and also inhibits the build up of pressure in the battery, so there is no danger of explosion. Commercial batteries used in electrical vehicles work at around 80–90°C, and over a voltage range of about 4 Volts. The team's prototype is just as effective even at temperatures as low as 60°C, and over a larger voltage range of 5V.

"This paves the way for safe, low cost and high energy density lithium metal battery for the mass markets of electric vehicles and stationary applications," says Renaud Bouchet, an electrochemical researcher at the Grenoble Institute of Technology, France, and the lead author.

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