Abstract: Provided are electrolyte solutions including both lithium difluoro(oxalato)borate and lithium tetrafluoroborate and a solvent component for use in lithium metal or anode-free rechargeable battery cell and methods of using the electrolyte solutions to improve capacity retention of the battery cells. Also provided are rechargeable battery systems including a lithium metal or anode-free battery cell and electrolyte solutions including both lithium difluoro(oxalato)borate and lithium tetrafluoroborate and a solvent component. The systems described herein exhibit improved capacity retention.

Abstract: An oxygen-reducing catalyst layer, and a method of making the oxygen-reducing catalyst layer, where the oxygen-reducing catalyst layer includes a catalytic material film disposed on a substrate with the use of physical vapor deposition and thermal treatment. The catalytic material film includes a transition metal that is substantially free of platinum. At least one of the physical vapor deposition and the thermal treatment is performed in a processing environment comprising a nitrogen-containing gas.

Abstract: Alloy compositions are described for use in anodes of lithium ion batteries. The alloy compositions contain (a) tin, (b) a second element that includes silicon, aluminum, or a combination thereof, (c) a third element that includes yttrium, a lanthanide element, an actinide element, or a combination thereof and an optional alkaline earth element, and (d) an optional transition metal. The alloy compositions are amorphous and remain amorphous even after multiple cycles of lithiation and delithiation.

Abstract: A rechargeable lithium-ion cell contains a positive electrode, negative electrode, charge-carrying electrolyte containing charge carrying medium and lithium salt, and an N-substituted or C-substituted phenothiazine compound dissolved in or dissolvable in the electrolyte. The substituted phenothiazine compound has an oxidation potential above the positive electrode recharged potential and serves as a cyclable redox chemical shuttle providing cell overcharge protection.

Abstract: A rechargeable lithium-ion cell contains a positive electrode, negative electrode, charge-carrying electrolyte containing charge carrying medium and lithium salt, and cycloaliphatic N-oxide compound dissolved in or dissolvable in the electrolyte. The N-oxide compound has an oxidation potential above the positive electrode recharged potential and serves as a cyclable redox chemical shuttle providing cell overcharge protection.

Abstract: A cathode composition for a lithium ion battery that contains lithium having the formula (a) Liy[M1(1?b)Mnb]O2 or (b) Liy[M1(1?b)Mnb]O1.5+c where 0?y<1, 0<b<1 and 0<c<0.5 and M1 represents one or more metal elements, with the proviso that for (a) M1 is a metal element other than chromium. The composition is in a form of a single phase having an O3 crystal structure that does not undergo a phase transformation to a spinel crystal structure when incorporated in a lithium-ion battery and cycled for 100 full charge-discharge cycles at 30 C and a final capacity of 130 mAh/g using a discharge current of 30 mA/g.

Abstract: A cathode composition for a lithium-ion battery having the formula Li[M1(1-x)Mnx]O2 where 0<x<1 and M1 represents one or more metal elements, with the proviso that M1 is a metal element other than chromium. The composition is in the form of a single phase having an O3 crystal structure that does not undergo a phase transformation to a spinel crystal structure when incorporated in a lithium-ion battery and cycled for 100 full charge-discharge cycles at 30° C. and a final capacity of 130 mAh/g using a discharge current of 30 mA/g.

Abstract: A battery of series-connected rechargeable lithium ion cells each of which contains a negative electrode; a negative electrode current collector; a positive electrode; a positive electrode current collector; and an electrolyte comprising charge carrying medium, lithium salt and cyclable redox chemical shuttle. The negative electrode has a larger irreversible first cycle capacity loss than that of the positive electrode, and is driven to a potential above that of the positive electrode if the cell is discharged to a state of cell reversal. The shuttle has an electrochemical potential above the positive electrode maximum normal operating potential, and prevents the negative electrode potential from reaching even higher and more destructive positive values during overdischarge. The current collector has a lithium alloying potential below the negative electrode minimum normal operating potential.

Abstract: A redox chemical shuttle comprising an aromatic compound substituted with at least one tertiary carbon organic group and at least one alkoxy group (for example, 2,5-di-tert-butyl-1,4-dimethoxybenzene) provides repeated overcharge protection in rechargeable lithium-ion cells.

Abstract: A cathode composition for a lithium-ion battery having the formula Li[M1(1-x)Mnx]O2 where 0<x<1 and M1 represents one or more metal elements, with the proviso that M1 is a metal element other than chromium. The composition is in the form of a single phase having an O3 crystal structure that does not undergo a phase transformation to a spinel crystal structure when incorporated in a lithium-ion battery and cycled for 100 full charge-discharge cycles at 30° C. and a final capacity of 130 mAh/g using a discharge current of 30 mA/g.