Surface-modified Li[Li0.2Ni0.17Co0.07Mn0.56]O2 nanoparticles with MgF2 as cathode for Li-ion battery

• MgF2 coating layer enhances the cycling and thermal stabilities of Li-rich material.
• The optimized coating content of MgF2 is found to be 1 wt.%.
• MgF2 coating can effectively suppress the undesirable growth of SEI layer.
• MgF2 coating facilitates the Li+ diffusion kinetics in Li-rich material.

Li-rich layered materials hold lots of promise as cathode for next-generation high performance Li-ion batteries. In this contribution, surface-modified layer-structured Li[Li0.2Ni0.17Co0.07Mn0.56]O2 (Li-rich) nanoparticles are employed as cathode for Li storage and transport studies. The results demonstrate that 1 wt.% MgF2-modified Li-rich electrode exhibits the best cycling capability, with capacity retention ratio of 86% after 50 cycles, much higher than that of pristine one (only 66%). In the meantime, the 1 wt.% MgF2 surface modified Li-rich electrode shows superior rate performance and thermal abuse treatments as well. Subsequent investigation indicates that the coated MgF2 layer can suppress the undesirable growth of solid electrolyte interphase (SEI) film and enhance the structure stability upon cycling. This coating technique provides the potentially rewarding avenue towards the development of high capacity Li-ion cathodes.