Low Li(+) binding affinity: An important characteristic for additives to form solid electrolyte interphases in Li-ion batteries

Abstract

Calculations are made of the lowest unoccupied molecular orbital (LUMO), chemical hardness (eta), dipole moment (mu), and binding energy with a Li+ ion for 32 organic molecules that are electrolyte additives for solid electrolyte interphase (SEI) formation in lithium-ion batteries (LIBs). The results confirm that both the LUMO and eta values are critical indicators of suitable SEI formation. The mu values of the additives are generally smaller than those of widely used solvents in LIBs. It is found that a low Li-ion binding affinity may be an important characteristic for SEI-forming additives. Li+ binding affinity is proposed as a factor in the computational screening process used to obtain promising additives. (C) 2011 Elsevier B.V. All rights reserved.