The invention discloses a cost-saving method to synthesize lithium nickel manganese cobalt (NMC) cathode materials for lithium-ion batteries (LIBs) especially Ni-rich single crystals. Lithium oxide (Li2O) salt is used as Li source in this method instead of LiOH-based salts (LiOH and LiOH·H2O) which has been used in existing NMC production. Compared to conventional LiOH-based salts route, the use of Li2O enables the same electrochemical performance of the final products while significantly reducing the number of processing steps and lowering the overall production cost and equipment attrition.