Ionics versus electronics, and the general case of mixed conductor

Abstract

The article emphasizes the importance of ion transport for solid state physics in view of the significance of ionic charge carriers for compositional changes and electrochemical applications, but also in view of their importance for defining the electronic charge carrier density. Special emphasis is given (i) to the mixed conductor as the general case which encompasses the pure electronic conductor and the pure ionic conductor as special cases, (ii) to the bridge between high temperature and room temperature situation and (iii) to the modern fields of interfacial ion transport and nano-ionics.

Aligning Electronic and Protonic Energy Levels of Proton‐Coupled Electron Transfer in Water Oxidation on Aqueous TiO2

“…[16][17][18] He noticed the isomorphism in the thermodynamic treatment between ionic and electronic charge carriers, and proposed representation of the thermodynamics of ionic defects using energy level diagrams similar to the electronic energy level diagrams used in semiconductor physics. [16][17][18] He noticed the isomorphism in the thermodynamic treatment between ionic and electronic charge carriers, and proposed representation of the thermodynamics of ionic defects using energy level diagrams similar to the electronic energy level diagrams used in semiconductor physics.…”

“…Furthermore, we utilize an appealing concept, of an acid-base scale developed in solid-state chemistry, [16][17][18] to elucidate the significance of the thermochemistry of PCET to thermodynamic overpotentials by aligning the electronic and protonic energy levels on the same potential-energy scale. Furthermore, we utilize an appealing concept, of an acid-base scale developed in solid-state chemistry, [16][17][18] to elucidate the significance of the thermochemistry of PCET to thermodynamic overpotentials by aligning the electronic and protonic energy levels on the same potential-energy scale.…”

Aligning Electronic and Protonic Energy Levels of Proton‐Coupled Electron Transfer in Water Oxidation on Aqueous TiO2

“…The system we study is the aqueous rutile TiO 2 (110) surface, and the reaction energies have been computed using a new method which we have developed. Furthermore, we utilize an appealing concept, of an acid‐base scale developed in solid‐state chemistry,16–18 to elucidate the significance of the thermochemistry of PCET to thermodynamic overpotentials by aligning the electronic and protonic energy levels on the same potential‐energy scale.…”

“…To further demonstrate the importance of the PCET energies in understanding the thermodynamic overpotential, we introduce the concept of an acid‐base scale developed by Maier to illustrate the thermodynamics of point defects in ionic solids 16–18. He noticed the isomorphism in the thermodynamic treatment between ionic and electronic charge carriers, and proposed representation of the thermodynamics of ionic defects using energy level diagrams similar to the electronic energy level diagrams used in semiconductor physics.…”

“…In acid‐base chemistry, H + (aq) is analogous to the ionic charge carrier in the defect chemistry of ionic solids, and thus the p K a values can be shown as protonic energy levels in a similar manner. Furthermore, he suggested that the electronic and ionic components can be linked by presenting both energy levels in the same energy scale 18. For interested readers, we refer you to Maier’s original papers16–18 for more detail.…”