Correction to: Nature Materials https://doi.org/10.1038/s41563-017-0013-1, published online 12 February 2018.

In the version of this Article originally published, in the y-axis label in Fig. 3a the unit was incorrect as ‘10–2 cm3 (STP) cm–1 cmHg–1’; it should have been ‘10–2 cm3 (STP) cm–3 cmHg–1’. In addition, in the schematic in the lower-right corner of Fig. 3e the label ‘\(< d_{i\rm{C}_4}\)’ was incorrect; it should have been ‘\(> d_{i\rm{C}_4}\)’.