**Acknowledgements**

The X‐ray microscopy experiments were performed at MISTRAL beamline at ALBA Synchrotron with the collaboration of ALBA staff. Alvaro Yamil Tesio is acknowledged for contribution to the experimental work. Work was funded by the Spanish Ministry of Economy and Competitiveness, through the "Severo Ochoa" Programme for Centres of Excellence in R&D (SEV‐ 2015–0496), and through project MAT2012‐39199‐C02‐01, by the Generalitat de Catalunya (grant 2014 SGR 1505), and by the European Commission in the Seventh Framework Programme FP7‐2010‐GC‐ELECTROCHEMICAL STORAGE, under contract no. 265971 "Lithium‐Air Batteries with Split Oxygen Harvesting and Redox processes (LABOHR)". M.O.M. acknowledges CSIC for a JAE‐DOC research contract cofinanced by the European Social Fund.
