Determining the oxidation states of dissolved transition metals in battery electrolytes from solution NMR spectra.

Abstract

Dissolved transition metal ions can induce peak shifts in the NMR spectra of degraded battery electrolytes. Here, we exploit this staightforward, accessible method to calculate magnetic moments for dissolved Ni2+, Mn2+, Co2+, and Cu2+; subsequent analysis of dissolution from LiMn2O4, LiNiO2, and LiNi0.5Mn1.5O4 shows that the dissolved metals are exclusively divalent.