The oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are the cornerstone of many renewable energy storage and conversion technologies such as metal-air batteries, fuel cells, and water electrolysis. [1][2][3] Both reactions, however, need highly active catalysts to achieve high efficiency since the oxygen electrode is a strongly irreversible system associated with high activation overpotential and sluggish kinetics. Noble metals (e.g., Pt) and their oxides (e.g., RuO 2 , IrO 2 ) have been found to be the most active catalysts for electrocatalytic reduction and evolution of molecular oxygen. However, their large-scale application is greatly prohibited by high cost, supply scarcity, and inferior durability. [4,5] On the other hand, as the universal choice of ORR catalyst, the OER activity of Pt is limited by the in situ formation of insulating platinum oxides in the process. IrO 2 and RuO 2 are unstable at high potentials due to the in situ transformation to higher-valent oxides, in spite of the highest activity towards OER. [6] To fulfill the demands in practical use, the development of lowcost yet durable bifunctional electrocatalysts with high activity toward both ORR and OER process is highly desired to reduce the cost and complexity of the renewable energy storage and conversion systems.Recent studies highlighted that transitional metal-N-doped carbon (NC) nanohybrids (MNC, MFe, Co, Ni, etc.) hold promise as substitutes of noble metal electrocatalysts in both acidic and alkaline medium. [7][8][9] In such catalysts, the presence of transitional metals helps to greatly improve the crystallinity and electrical conductivity of carbon matrix by catalytic graphitization upon preparation at high temperature, which in turn function to protect the metals from corrosion and aggregation during the electrochemical reactions. [10,11] More importantly, the interaction and synergy of metal species, the doped N species, and carbon lattice create sufficient localized reactive sites by modifying the charge distribution on carbon surface via the promoted electron transfer effect, which changes the local work function for O 2 adsorption and consequently facilitate the ORR or OER. [12,13] Very recently, the synergistic effect of metal@C nanoparticles and neighboring metal-N x coordination sites has been demonstrated to promote the O 2 adsorption The oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are cornerstone reactions for many renewable energy technologies. Developing cheap yet durable substitutes of precious-metal catalysts, especially the bifunctional electrocatalysts with high activity for both ORR and OER reactions and their streamlined coupling process, are highly desirable to reduce the processing cost and complexity of renewable energy systems. Here, a facile strategy is reported for synthesizing double-shelled hybrid nanocages with outer shells of Co-N-doped graphitic carbon (Co-NGC) and inner shells of N-doped microporous carbon (NC) by templating against core-shell metal-orga...