In practice, the macroscopic structural and surface properties of the pyrolyzed paper heavily influence LIG-E wetting and electrochemical responses in functional devices. To explore these features, we studied LIG-E using electron microscopy, and discovered that the fibrous structure of cellulose is conserved after pyrolysis (Fig. and). As anticipated, analysis of energy-dispersive X-ray (EDX) spectra revealed that pyrolysis successfully removed over 95% of the oxygen atoms from the bulk paper material (Fig. ). Interestingly, we did not detect any significant incorporation of nitrogen or sulfur atoms in the carbonaceous structure (Fig. ).