This invention is a follow-up work of our precious patents: US11862794B2 and US20220112094A1. Both titled 'Cost effective synthesis of oxide materials for lithium-ion batteries". Based on previous work, in this invention, one-step method to synthesize Ni-rich monocrystalline NMC is developed. The one-step method is: heat a solid hydroxide precursor comprising NixMnyMzCo1-x-y-z(OH)2 with Li2O to produce monocrystalline lithium nickel manganese cobalt oxide having a formula LiNiXMnyMzCo1-x-y-zO2.The time at high temperature annealing is reduced to 1 minute, making the synthesis of Ni-rich monocrystalline more cost effective.