  Density functional theory and ab initio molecular dynamics simulations are
applied to investigate the migration of Mn(II) ions to above-surface sites on
spinel Li(x)Mn(2)O(4) (001) surfaces, the subsequent Mn dissolution into the
organic liquid electrolyte, and the detrimental effects on graphite anode solid
electrolyte interphase (SEI) passivating films after Mn(II) ions diffuse
through the separator. The dissolution mechanism proves complex, the
much-quoted Hunter disproportionation of Mn(III) to form Mn(II) is far from
sufficient. Key steps that facilitate Mn(II) loss include concerted
liquid/solid-state motions, proton-induced weakening of Mn-O bonds forming
mobile OH- surface groups, and chemical reactions of adsorbed decomposed
organic fragments. Mn(II) lodged between the inorganic Li(2)CO(3) and organic
lithium ethylene dicarbonate (LEDC) anode SEI components facilitates
electrochemical reduction and decomposition of LEDC. These findings help inform
future design of protective coatings, electrolytes, additives, and interfaces.
