LiNbO 3 Coating and F - Doping Stabilize the Crystal Structure and Ameliorate the Interface of LiNi 0.88 Co 0.06 Mn 0.03 Al 0.03 O 2 to Improve the Electrochemical Properties and Safety Capability.

Ni-rich layered materials Li[Ni x Co y Mn z Al 1- x- y - z ]O 2 ( x > 0.8) are regarded as the competitive cathode for practical applications in lithium-ion batteries owing to the large discharging capacity. Nevertheless, the strong oxidation activity, the poor structure, and the thermal stability at the electrode-electrolyte interface would lead to much trouble, for example, inferior electrochemical properties and acute safety issues. To ameliorate the above problems, this work reports a strategy for the double modification of F - doping and LiNbO 3 covering in LiNi 0.88 Co 0.06 Mn 0.03 Al 0.03 O 2 cathode via using high-temperature calcining and ball-milling technology. As a result, the cathodes after F - doping and LiNbO 3 covering not only demonstrate a more stabilized crystal structure and particle interface but also reduce the release of high-activity oxygen species to ameliorate the thermal runaway. The electrochemical tests show that the LiNbO 3 -F - -modified cathode displays a superior rate capability of 159.3 mAh g -1 at 10.0 C and has the predominant capability retention of 92.1% in the 200th cycle at 25 °C, much superior than those (125.4 mAh g -1 and 84.0%) of bare cathode. Thus, the F- doped and LiNbO 3 -coated Ni-rich oxides could be a promising cathode to realize the high capacity and a stabilized interface.