In some designs, it may be advantageous to have a total salt concentration in the electrolyte in the range from around 0.8M to around 2.0M, while utilizing a small fraction of fluoroethylene carbonate (FEC) co-solvent in electrolyte (e.g., in the range from around 3 to about 20 vol. %, as a fraction of all the solvents in the electrolyte), some amount of non-FEC cyclic carbonates (e.g., in the range from around 5 to about 35 vol. %, as a fraction of all the solvents in the electrolyte) and some amount of the LMP co-solvent(s) (e.g., in the range from around 20 to about 70 vol. %, as a volume fraction of all the solvents in the electrolyte). In some designs, it may be advantageous to for the electrolyte composition to additionally comprise at least one linear carbonate. In some designs, it may be advantageous for the electrolyte to comprise a mixture of two or more linear carbonates. In some designs, it may be advantageous for the fraction of linear carbonate(s) to constitute from about 5 vol. % to about 50 vol. % (as a volume fraction of all the solvents in the electrolyte). In some designs, it may be even more advantageous for the fraction of linear carbonate(s) to constitute from about 10 vol. % to about 30 vol. % (as a volume fraction of all the solvents in the electrolyte). In some designs, it may be advantageous for at least some of the linear carbonates to comprise at least one carbonyl (═O) side group in their molecular structure. In some designs, it may be preferable for at least one of the linear carbonates or the only linear carbonate or the mixture of all linear carbonates in the electrolyte to exhibit a melting point from around ?10° C. to around ?60° C. The size of the linear carbonate molecules may play a significant role in cell performance. For example, shorter chain linear carbonates in the electrolyte may result in better rate performance and, in some cases, better cycle stability. However, too short linear carbonates may also lead to cycle stability reduction. In some designs, the average number of atoms in the linear carbonates in the electrolyte may preferably be in the range from about 12 to about 26 per carbonate molecule. In some designs, it may be advantageous for the electrolyte to comprise diethyl carbonate (DEC) as a linear carbonate or a component of a linear carbonate mixture. DEC-comprising electrolytes may exhibit better rate performance (better capacity retention at higher rates). Additionally, electrolytes comprising DEC may offer high cycle stability.