Thermodynamic, Kinetic and Electrochemical Studies on Mixed Proton, Oxygen Ion and Electron (Hole) Conductors

Technical Report · Mon Apr 25 04:00:00 EDT 2022

DOI:https://doi.org/10.2172/1864586· OSTI ID:1864586

Virkar, Anil V. ^[1]

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1. Univ. of Utah, Salt Lake City, UT (United States); University of Utah

The report contains a summary of work done during the period of performance September 1, 2015 through August 31, 2021. The principal objective of the work was to conduct thermodynamic, kinetic and electrochemical studies on mixed proton, oxygen ion and electron (hole) conductors. The project also involved studies on cation conductors such as Li⁺ and Na⁺ ion conductors of particular relevance to batteries. The work involved theory and experiments. Since any use of ionic conductors necessarily entails two electrodes, electrode reactions are central to the overall transport processes from one electrode, through the electrolyte, to the other electrode. The role of interfaces and electrochemical reactions is thus of central importance. Transport processes in fuel cells, electrolyzers, lithium batteries and sodium batteries were examined using linear non-equilibrium thermodynamics, which is based on the assumption of small departures from thermodynamic equilibrium. The main approach involved expressing transport processes using the Onsager equations which naturally include coupling of thermodynamic flows and thermodynamic forces. The basic tenet of linear nonequilibrium thermodynamics is the existence of local thermodynamic equilibrium which means that all thermodynamic functions are locally defined. Thus, chemical potentials of various species are defined locally as a function of position and also of time. The existence of local thermodynamic equilibrium has fundamental implications concerning transport of electronic species through a predominantly ionic conductor.

• Research Organization: Univ. of Utah, Salt Lake City, UT (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES). Materials Sciences & Engineering Division
• DOE Contract Number: FG02-03ER46086
• OSTI ID: 1864586
• Report Number(s): DOE-UTAH-FG02-03ER46086
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY