CATL’s sodium-ion battery on display at a trade showVCG/VCG via Getty Images On 5 February, a black sedan was speeding down an icy track in northern China at 95 kilometres per hour when its tyre burst, releasing a puff of white into the -32°C air. The car coasted to a stop without spinning into the snow. This was meant to demonstrate that even the harshest conditions were no barrier to the auto-maker Changan’s new line of electric vehicles, which includes the first mass-produced EV with a sodium...