A rechargeable electrochemical device, comprising: an ionically conducting liquefied gas electrolyte comprising a liquefied gas solvent and a lithium salt; a housing enclosing the liquefied gas electrolyte and structured to provide a pressurized condition to the liquefied gas electrolyte; and at least two conducting electrodes in contact with the liquefied gas electrolyte; wherein: the liquefied gas electrolyte operates at a vapor pressure above an atmospheric pressure of 100 kPa at a room temperature of 293.15 K; the liquefied gas electrolyte is capable of being placed under a compressive pressure equal to, or greater than, the liquefied gas solvent's vapor pressure at room temperature when the compressive pressure is applied, thereby keeping the liquefied gas electrolyte in a liquid phase; and the liquified gas electrolyte remains in a single liquid phase at 293 K; the liquefied gas electrolyte further comprises one or more additives, thereby providing the liquefied gas electrolyte in combination with the liquefied gas solvent and the lithium salt; the one or more additives are selected from the group consisting of: cyclic carbonates, non-cyclic carbonates, cyclic ethers, non-cyclic ethers and nitriles; wherein the molar ratio of the lithium salt to the additive is between 0.3 to 3.0 whereby the lithium salt is soluble to at least 0.4M in the liquified gas electrolyte; and the liquified gas electrolyte has a conductivity of at least 3.5 mS/cm at 293 K. an ionically conducting liquefied gas electrolyte comprising a liquefied gas solvent and a lithium salt; a housing enclosing the liquefied gas electrolyte and structured to provide a pressurized condition to the liquefied gas electrolyte; and at least two conducting electrodes in contact with the liquefied gas electrolyte; wherein: the liquefied gas electrolyte operates at a vapor pressure above an atmospheric pressure of 100 kPa at a room temperature of 293.15 K; the liquefied gas electrolyte is capable of being placed under a compressive pressure equal to, or greater than, the liquefied gas solvent's vapor pressure at room temperature when the compressive pressure is applied, thereby keeping the liquefied gas electrolyte in a liquid phase; and the liquified gas electrolyte remains in a single liquid phase at 293 K; the liquefied gas electrolyte further comprises one or more additives, thereby providing the liquefied gas electrolyte in combination with the liquefied gas solvent and the lithium salt; the one or more additives are selected from the group consisting of: cyclic carbonates, non-cyclic carbonates, cyclic ethers, non-cyclic ethers and nitriles; wherein the molar ratio of the lithium salt to the additive is between 0.3 to 3.0 whereby the lithium salt is soluble to at least 0.4M in the liquified gas electrolyte; and the liquified gas electrolyte has a conductivity of at least 3.5 mS/cm at 293 K. the liquefied gas electrolyte operates at a vapor pressure above an atmospheric pressure of 100 kPa at a room temperature of 293.15 K; the liquefied gas electrolyte is capable of being placed under a compressive pressure equal to, or greater than, the liquefied gas solvent's vapor pressure at room temperature when the compressive pressure is applied, thereby keeping the liquefied gas electrolyte in a liquid phase; and the liquified gas electrolyte remains in a single liquid phase at 293 K; the liquefied gas electrolyte further comprises one or more additives, thereby providing the liquefied gas electrolyte in combination with the liquefied gas solvent and the lithium salt; the one or more additives are selected from the group consisting of: cyclic carbonates, non-cyclic carbonates, cyclic ethers, non-cyclic ethers and nitriles; wherein the molar ratio of the lithium salt to the additive is between 0.3 to 3.0 whereby the lithium salt is soluble to at least 0.4M in the liquified gas electrolyte; and the liquified gas electrolyte has a conductivity of at least 3.5 mS/cm at 293 K.