Enhanced rate capability and cycling stability of lithium-rich cathode material Li1.2Ni0.2Mn0.6O2 via H3PO4 pretreating and accompanying Li3PO4 coating

H 3 PO 4 pretreated and Li 3 PO 4 coated Li-rich materials Li 1.2 Ni 0.2 Mn 0.6 O 2 have been prepared via hydrothermal followed by a facile modified method. The pretreated process partially extracts Li and O from lattice, results in pre-activation of Li 2 MnO 3 component and the formation of spinel phase. A stable Li 3 PO 4 coating is formed on the surface of the material during the subsequent heat treatment. H 3 PO 4 pretreatment and Li 3 PO 4 coating are skillfully combined using a simple method. Electrochemical studies exhibit that the electrochemical performance of Li 1.2 Ni 0.2 Mn 0.6 O 2 is obviously improved after surface modification. The surface treated material with 0.04 mol L −1 H 3 PO 4 shows more excellent electrochemical properties than those of Li 1.2 Ni 0.2 Mn 0.6 O 2 cathode, with a high specific discharge capacity of 262.6 mAh g −1 at 0.1 C, a great capacity retention of 92.2% at 1 C after 100 cycles, and an outstanding rate capability reaching 105.4 mAh g −1 at 10 C. The enhanced performance is caused by the formation of spinel phase and Li 3 PO 4 coating layer, which can accelerate the migration of Li + and facilitate the charge transfer reaction. The Li 3 PO 4 coating also inhibits the dissolution of transition metal ions and enhances the stability of electrode/electrolyte interface.