For the first time, TU Delft researchers led by Prof. Fokko Mulder have produced an integrated battery electrolysis system – known as a ‘battolyser’ – that can not only store or supply electricity efficiently as a battery but can also split water into hydrogen and oxygen using electrolysis. This week the first article about it was published Energy & Environmental Science, and a research programme has been awarded funding by the Technology Foundation STW with the support of several companies.