Abstract: An anode for a lithium or lithium-ion cell, protected with an SEI by pre-treatment in an SEI-formation cell, is stable for cell cycling even in the presence of substantial water in the cell electrolyte. A method for making the protected anode includes forming an SEI on a lithium or lithium-ion electrode by performing multiple charge/discharge cycles on the electrode in a first cell having an SEI formation electrolyte to produce the protected anode. The SEI formation electrolyte includes an ionic liquid having at least one of eight organic cations.

Abstract: An anode for a Li-ion cell, protected with an SEI by pre-treatment in an SEI-formation cell, is stable for cell cycling even in the presence of substantial water in the cell electrolyte. A method for making the protected anode includes forming an SEI on a lithium electrode by performing multiple charge/discharge cycles on the electrode in a first cell having an SEI formation electrolyte to produce the protected anode. The SEI formation electrolyte includes an ionic liquid having at least one of eight organic cations.

Abstract: An electrolyte for Li-ion and other secondary electrochemical cells includes an FSI anion and at least one of methyltriethylphosphonium; trimethylisobutylphosphonium; methyltributylphosphonium; and trihexyltetradecylphosphonium. The electrolyte uniquely enables stable cell cycling even when water is present in the electrolyte at levels as high as 5000 ppm. Methyltriethylphosphonium and trimethylisobutylphosphonium-containing electrolytes are particularly effective in this water-stabilizing capacity.

Abstract: An electrolyte for Li-ion and other secondary electrochemical cells includes an FSI anion and at least one of methyltriethylphosphonium; trimethylisobutylphosphonium; methyltributylphosphonium; and trihexyltetradecylphosphonium. The electrolyte uniquely enables stable cell cycling even when water is present in the electrolyte at levels as high as 5000 ppm. Methyltriethylphosphonium and trimethylisobutylphosphonium-containing electrolytes are particularly effective in this water-stabilizing capacity.

Abstract: An anode for a Li-ion cell, protected with an SEI by pre-treatment in an SEI-formation cell, is stable for cell cycling even in the presence of substantial water in the cell electrolyte. A method for making the protected anode includes forming an SEI on a lithium electrode by performing multiple charge/discharge cycles on the electrode in a first cell having an SEI formation electrolyte to produce the protected anode. The SEI formation electrolyte includes an ionic liquid having at least one of eight organic cations.

Abstract: Pyrrolidinium based room temperature ionic liquids, and phosphorous and arsenic analogues, are used as electrolytes in energy storage devices including secondary lithium batteries, supercapacitors and asymmetric battery-supercapacitors. The electrolytes preferably contain lithium ions as the charge-carrying species. The electrolytes are in a liquid state at the operating temperature.