Road transportation is going electric — though not fast enough. Road vehicles account for 19% of total global energy consumption and 15% of all greenhouse gas emissions1,2. Compared with internal combustion engine vehicles, electric vehicles have much higher well-to-wheel efficiency (that is, the fraction of energy from the oil in the well that is delivered to the wheels of the vehicle), and can improve local air quality and reduce greenhouse gas emissions. At present, only about 10 million of the roughly 1.5 billion cars, buses and trucks in the world are electric (corresponding to under 0.7%)3. However, in 2020, around 3 million of the 65 million cars sold globally were electric (corresponding to 4.6%), and concerns about climate change are motivating governments to introduce incentives and regulations to rapidly increase the share of electric vehicles.