(i) Are the metal atoms in the reduced Cu-In/Sn materials present as alloys or separate metallic phases?(ii) What are the Cu/In or Cu/Sn stoichiometries in the alloy phase? (iii) What is the level of crystallinity? What are the metal oxidation states and oxidic contributions? (iv) What is the ef fect of the applied potentials? Are In or Sn leaching or enriching during operation?