Lithium batteries started an avalanche of innovation when they became widely available, largely because they could hold significantly more energy by weight than other contemporary chemistries. Touchscreen smartphones, drones, all-day laptops, long-range electric cars and the first generation of battery-powered aircraft were some of the results.

But more energy storage is always better – you can either make things last longer, or weigh less – and manufacturers have been racing to raise the bar with next-gen battery technologies. One key metric in the aviation world is specific energy – the amount of energy stored per kilogram of battery, and CATL says it's ready to set a new benchmark.