The dependence of lithium cycling efficiency on stack pressure was studied for several electrolytes. To evaluate the cycling efficiency E, we calculated the figure of merit (FOM) of lithium as FOM = 1/(1-E). The effect of solvents on the FOM change with pressure was examined for LiAsF6 solute electrolytes containing 2-methyltetrahydrofuran (2MeTHF), ethylene carbonate (EC)/2MeTHF, propylene carbonate (PC), or EC/PC. The electrolyte LiAsF6-EC/2MeTHF showed the largest FOM at (80 at 125 kg/cm2). With the electrol LiAsF6-PC and LiAsF6-EC/PC, FOM was less dependent on stack pressure than it was with the electrolytes LiAsF6-2MeTHF and EC/2MeTHF, probably because a different separator was used for the former electrolytes. Examining the effect of the solute on the FOM change with pressure showed that the FOMs for LiPF6- and LiCF3SO3-EC/2MeTHF reached maximum values at 50 and 75 kg/cm2, respectively, and that the FOM values for LiAsF6-EC/2MeTHF increased with increasing stack pressure up to at least 125 kg/cm