The atom-scale structure and properties of the interface between polymer electrolyte and electronic conductor are of great interest for novel electrochemical power sources including fuel cell, lithium batteries, and supercapacitors. Scanning tunneling microscopy, a well-known tool for imaging electronically conducting surface, is used to investigate Nafion polymer electrolyte coated Pt or highly ordered pyrolytic graphite. Periodic atom-scale patterns at the interface between Nafion and highly ordered pyrolytic graphite are obtained. In addition, in situ, real-time visualization of the atom-scale interface structure is realized upon changing the electrochemical potential of the substrates. The results suggest that a highly convergent resonant tunneling electron wave can penetrate a thick (200-1000 nm) recast Nafion (polymer electrolyte) coating and reach the substrates. A theory based on electron resonant tunneling is established to explain this phenomenon. It is expected that this method can be applied for real-time atom-scale visualization of other polymer/conductor interfaces.
ASJC Scopus subject areas
- Physics and Astronomy(all)