Surface engineering is an effective strategy to restrain the generation of rocksalt NiO phase on surface of layered LiNi0.815Co0.5Al0.035O2 (NCA) primary nanoparticles,a representative Ni-rich layered oxides cathode materials,Herein,we demonstrate the kilogram-scale synthesis of few-layer reduced graphene oxide (rGO) conformably coated NCA primary nanoparticles cathode materials by a mechanical wet ball-milling strategy.The lightening rGO coating layer effectively avoids the direct contact of electrolyte and NCA with rapid electrons transfer.As a result,the as-obtained NCA@rGO hybrids with only 1.0 wt% rGO content can deliver a high specific capacity (196 mAh g-1 at 0.2 C) and fast charge/discharge capability (127 mAh g-1 at 5 C),which is much higher than the corresponding NCA nanoparticles (95 mAh g-1 at 5 C).Even after 100 cycles at 1 C,91.7% of initial reversible capacity is still maintained.Furthermore,a prismatic pouch cell (240 mAh) is also successfully assembled with the commercial graphite anode.