NOVELTY - Synthesizing a mixture of molecules or salts having low symmetry by using mixed Grignard reagents, is claimed.    USE - The method is useful for synthesizing a mixture of molecules or salts having low symmetry that are used in battery and electrochemical double layer capacitor (all claimed), as electrolytes in electronic devices (memory devices including static, permanent and dynamic RAM), energy storage devices (super capacitors or ultra capacitors, and electrolytic capacitors), dye-sensitized solar cells and fuel cells, and as heat transfer medium, high temperature reaction and/or extraction media.    ADVANTAGE - The method provides composition that: exhibit wider electrochemical voltage stability window compared to the conventional electrolytes and desired combinations of at least two of thermodynamic stability, low volatility, wide liquidus range and ionic conductivity; and improves electrochemical double layer capacitor cycle life, the safety and reliability of battery operation and battery cycle life.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for:    (1) synthesizing (S1) a mixture of molecules, comprising reacting a reactant with a mixture of at least two Grignard reagents having mole fractions of fa and fb to produce a mixture of molecules having selective mole fractions;    (2) the mixture of molecules having low average symmetry, prepared by the method;    (3) a battery comprising: an anode; a cathode; a separator between the anode and the cathode; and an electrolyte composition in contact with the anode, the cathode, and the separator, where the electrolyte composition comprises: the mixture of phosphonium ionic liquids, or phosphonium salts dissolved in a solvent and the phosphonium ionic liquids or phosphonium salts have a controlled cation distribution; and    (4) an electrochemical double layer capacitor (EDLC) comprising: a positive electrode; a negative electrode; a separator between the first electrode and the second electrode; and an electrolyte composition in contact with the positive electrode, the negative electrode and the separator, where the electrolyte composition comprises a mixture of phosphonium ionic liquids, or phosphonium salts dissolved in a solvent and the phosphonium ionic liquids or phosphonium salts have a controlled cation distribution.