title: Experimental and Computational Analysis of the Solvent-Dependent O2/Li(+)-O2(-) Redox Couple: Standard Potentials, Coupling Strength, and Implications for Lithium-Oxygen Batteries.
abstract: Understanding and controlling the kinetics of O2 reduction in the presence of Li(+)-containing aprotic solvents, to either Li(+)-O2(-) by one-electron reduction or Li2 O2 by two-electron reduction, is instrumental to enhance the discharge voltage and capacity of aprotic Li-O2 batteries. Standard potentials of O2 /Li(+)-O2(-) and O2/O2(-) were experimentally measured and computed using a mixed cluster-continuum model of ion solvation. Increasing combined solvation of Li(+) and O2(-) was found to lower the coupling of Li(+)-O2(-) and the difference between O2/Li(+)-O2(-) and O2/O2(-) potentials. The solvation energy of Li(+) trended with donor number (DN), and varied greater than that of O2 (-) ions, which correlated with acceptor number (AN), explaining a previously reported correlation between Li(+)-O2(-) solubility and DN. These results highlight the importance of the interplay between ion-solvent and ion-ion interactions for manipulating the energetics of intermediate species produced in aprotic metal-oxygen batteries.
authors.affiliation: Department of Mechanical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, 02139, USA.
authors.forename: David G
authors.initials: DG
authors.lastname: Kwabi
authors.affiliation: Liox Power Inc, 129 North Hill Ave, Suite 103, Pasadena, CA, 911106, USA.|Oak Ridge National Lab, Chemical Sciences Division, 1 Bethel Valley Rd, Oak Ridge, TN, 37831-6119, USA.
authors.forename: Vyacheslav S
authors.initials: VS
authors.lastname: Bryantsev
authors.affiliation: Department of Materials Science and Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, 02139, USA.
authors.forename: Thomas P
authors.initials: TP
authors.lastname: Batcho
authors.affiliation: Department of Chemistry and Materials Science, Moscow State University, Moscow, 119992, Russia.
authors.forename: Daniil M
authors.initials: DM
authors.lastname: Itkis
authors.affiliation: Department of Materials Science and Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, 02139, USA.
authors.forename: Carl V
authors.initials: CV
authors.lastname: Thompson
authors.affiliation: Department of Mechanical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, 02139, USA. shaohorn@mit.edu.|Department of Materials Science and Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, 02139, USA. shaohorn@mit.edu.
authors.forename: Yang
authors.initials: Y
authors.lastname: Shao-Horn
keywords: acid-base interactions; lithium; oxygen electrochemistry; solvation; superoxide