A facile and scalable method is developed for the high-efficiency synthesis of Co, N-doped carbon nanocages catalyst for the oxygen reduction reaction (ORR). During the synthesis, the precursors are uniformly distributed on the surface of potassium chloride (KCl) by high-energy ball milling. As evidenced, the N and Co elements are successfully doped and distributed uniformly on the surface of carbon nanocages. Owing to the distinctive nanocage architecture and the synergistic effects of Co, N and Co-N-x coordination, the obtained Co, N-CNC-800 shows efficient ORR catalytic activity with an onset potential of 0.924 V (vs. RHE), and the number of electron transfer (n) is approximately 3.4. Furthermore, its stability and methanol tolerance are far superior to those of commercial 40% Pt/C. This simple and universal synthesis strategy is expected to be widely applied in the preparation of other heteroatom-doped carbon nanocages as catalysts in hydrogen fuel cells. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.