S-1 Supporting Information Origin of Enhanced Cyclability in Covalently Modified LiMn 1.5 Ni 0.5 O 4 Cathodes Kenneth E. Madsen, Kevin A. Wade, Richard T. Haasch, D. Bruce Buchholz, Kimberly L. Bassett, Bruno G. Nicolau, and Andrew A. Gewirth* Department of Chemistry University of Illinois at Urbana-Champaign 600 S. Mathews Ave. Urbana, IL 61801 USA K. E. Madsen, K. A. Wade, Dr. K. L. Bassett, Dr. B. G. Nicolau, Prof A. A. Gewirth University of Illinois at Urbana-Champaign, Department of Chemistry, Urbana, IL 61801 Dr. R. T. Haasch University of Illinois at Urbana-Champaign, Frederick Seitz Materials Research Laboratory, Urbana, IL 61801 Dr. D. B. Buchholz Northwestern University, Department of Materials Science and Engineering, Evanston, IL 60208