Correction to: Nature Energy https://doi.org/10.1038/s41560-019-0490-3, published online 4 November 2019.

In the version of this Article originally published, in the Acknowledgements, in the sentence beginning “The computational studies were supported by”, ‘X-ray photoemission spectroscopy (XPS)’ was inadvertently left out; the sentence has now been amended to read “The computational studies and X-ray photoemission spectroscopy (XPS) were supported by the US Department of Energy, Basic Energy Sciences, Division of Materials Science and Engineering”.