The rise of electric cars could leave us with a big battery waste problem

Carmakers, recyclers and tech start ups are working to solve the question of how to deal with lithium-ion batteries when they wear out

The drive to replace polluting petrol and diesel cars with a new breed of electric vehicles has gathered momentum in recent weeks. But there is an unanswered environmental question at the heart of the electric car movement: what on earth to do with their half-tonne lithium-ion batteries when they wear out?

British and French governments last month committed to outlaw the sale of petrol- and diesel-powered cars by 2040, and carmaker Volvo pledged to only sell electric or hybrid vehicles from 2019.