A lithium-ion battery having an anode electrode, a cathode electrode and a non-aqueous solvent lithium electrolyte. At least one cyclophosphazene is added to the non-aqueous solvent lithium electrolyte, which cyclophosphazene acts as a flame-retardant material. The non-aqueous solvent lithium electrolyte is preferably a carbonate-based electrolyte and the preferred cyclophosphazene is hexamethoxycyclotriphosphazene.