Positive electrodes with active materials and temporary lithium additives for lithium ion electrochemical cells

Abstract

Provided are methods of introducing additional lithium ions into lithium-ion electrochemical cells as well as positive electrodes, comprising these additional lithium ions. A method may involve introducing a temporary lithium additive into a positive electrode, such as mixing the additive into slurry used for coating the electrode. The positive electrode also comprises a positive active material, different from the temporary lithium additive and used as a source of primary lithium ions. The positive active material is operable to release and also later to receive lithium ions during cycling. The temporary lithium additive is operable to release additional lithium ions during its decomposition, but not to receive any lithium ions thereafter. The amount of these additional lithium ions may be selected based on expected lithium ion losses in the cell. The temporary lithium additive may decompose when applying a voltage between the electrodes, e.g., during initial cycling.