Fluorine-Doped Carbon Surface Modification of Li-Rich Layered Oxide Composite Cathodes for High Performance Lithium-Ion Batteries

Fluorine (F)-doped carbon modified lithium rich layered oxides Li1.2Mn0.54Ni0.13Co0.13O2 (LMCNO@C-F) are synthesized by a facile sol-gel process. In this constructed architecture, the F-doped carbon surface modification layers can not only enhance the electronic conductivity of the overall electrode but also avoid the direct exposure of LNMCO to the electrolyte. As a result, The LMCNO@C-F sample exhibits a high reversible capacity (289.5 mA h g(-1) at 0.1 C), excellent rate capability (263.6, 218.9, 182.9, and 108.6 mA h g(-1) at 0.5, 1, 5, and 10 C, respectively), and superior cycling stability (with a high capacity retention of 88.5% at 5 C after 500 cycles). The enhanced performance is ascribed to the formed metal fluorides (Mn-F bond) and a strong electronic coupling between F-doped carbon and bulk LMNCO, which can greatly enhance the structure stability and electronic conductivity of LMNCO cathode materials.