Abstract: A lithium-ion rechargeable battery with carbon-based anode comprising a cathode based on a lithium intercalating compound, such as a lithium-free or a lithiated compound, a non-aqueous lithium ion-conducting electrolyte and a carbon-based anode, wherein said carbon-based anode comprises, as the starting active material before the first cycle of the battery, the potassium intercalated graphite of the formula KC.sub.8 (first stage potassium graphite intercalation compound), optionally together with a binder. After the first discharge cycle of the battery, most potassium ions are released from the intercalation compound, but the structure of the anode compound maintains an "expanded" interlayer distance, which greatly enhances the kinetics of the electrochemical process, thus resulting in a high-rate carbon anode. The positive counterelectrode material may be chosen both among lithiated and among lithium-free intercalation compounds.

Abstract: A molten salt electrochemical system for battery applications comprises tetravalent sulfur as the active cathode material with a molten chloroaluminate solvent comprising a mixture of AlCl.sub.3 and MCl having a molar ratio of AlCl.sub.3 /MCl from greater than 50.0/50.0 to 80/20.

Abstract: A molten salt electrochemical system for battery applications is provided mprising aluminum as the anode, positive oxidation states of either iodine or sulfur as the cathode, and a low-melting molten mixture of aluminum chloride and alkali chloride disposed between the anode and cathode and in contact with each.