Epoxy-functionalized silane grafting enhances the cycling performances of Li1.2Ni0.13Co0.13Mn0.54O2 cathode materials

Epoxy-functionalized silane (KH560) modified Li 1.2 Ni 0.13 Co 0.13 Mn 0.54 O 2 materials are prepared by a facile chemical grafting method for the first time. X-ray diffraction confirms that the crystal structure of Li 1.2 Ni 0.13 Co 0.13 Mn 0.54 O 2 is not affected by the KH560 modification. Scanning electron microscopy and transmission electron microscopy results prove that KH560 is homogeneously grafted on the Li 1.2 Ni 0.13 Co 0.13 Mn 0.54 O 2 surface with a thickness of 3–5 nm. The electrochemical tests reveal that the 1.0 wt% KH560 modified Li 1.2 Ni 0.13 Co 0.13 Mn 0.54 O 2 cathodes retain 92.88% (1 C) and 98.24% (5 C) capacity retentions after 100 cycles, respectively, far higher than 83.09% (1 C) and 50.68% (5 C) of the pristine. The improved cycling performances are mainly attributed to the fact that the X-O-M bonds stabilize the surface oxygen and resist the parasitic reactions during cycling, which further can suppress the structure degradation and the impedance increase. This work provides a facile and effective modification method to optimize the interfacial structures of Li 1.2 Ni 0.13 Co 0.13 Mn 0.54 O 2 and/or other cathode materials.