Dual Roles of Li3N as an Electrode Additive for Li-Excess Layered Cathode Materials: A Li-Ion Sacrificial Salt and Electrode-Stabilizing Agent

Li2CO3-passivated Li3N with high stability is prepared by aging Li3N powder in dry air, and is then used as an electrode additive for a Li(Li0.18Ni0.15Co0.15Mn0.52)O-2 (LLMO) cathode material. The material shows a large irreversible capacity of 800mAhg(-1) during the first charge, with the formation of a Li2N intermediate product. Acting as a Li+ sacrificial salt for a LLMO(+)/graphite(-) Li-ion battery, 2wt% Li3N results in a 10% increase in discharge capacity. The Li2N 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.