This work reports the use of mixtures of gamma-butyrolactone (GBL) and ethyl acetate (EA), with and without ethylene carbonate (EC), as solvents for lithium bis(oxalato)borate (LiBOB) salt as potential electrolytes for Li-ion cells. The effects of salt concentration, ethylene carbonate (EC) content, and temperature on the conductivity and viscosity of the mixture are reported. Results indicate that the best electrolyte for high-temperature application is that which contains 1 kmol m(-3) LiBOB in GBL + EA + EC of composition 1:1:0.1 (wt). For low-temperature applications, the best electrolyte is that which contains 0.7 kmol m(-3) LiBOB in GBL + EA + EC of composition 1:1:0 (wt). The product of conductivity with viscosity was essentially independent of temperature but was dependent on solvent composition showing that at fixed salt concentration, the viscosity is the major criteria affecting electrolyte conductivity rather than dielectric constant. (C) 2010 Elsevier B.V. All rights reserved.