Dual Roles of Li N as an Electrode Additive for Li-Excess Layered Cathode Materials: A Li-Ion Sacrificial Salt and Electrode-Stabilizing Agent.

Li CO -passivated Li N with high stability is prepared by aging Li N powder in dry air, and is then used as an electrode additive for a Li(Li Ni Co Mn )O (LLMO) cathode material. The material shows a large irreversible capacity of 800 mA h g during the first charge, with the formation of a Li N intermediate product. Acting as a Li sacrificial salt for a LLMO(+)/graphite(-) Li-ion battery, 2 wt % Li N results in a 10 % increase in discharge capacity. The Li N intermediate product reacts with the electrolyte, forming a uniform and regular surface film on the cathode. Moreover, chemical bonding between LLMO and N improves the electrode stability, resulting in excellent electrochemical performance.