Uniform nano/micro-spherical MoO2/Mo2CTx (T = O) heterostructures have been synthesized through a heterocatalytic reaction with subsequent facile calcinations. Given the high activity of HxMoO3/C precursors, this strategy opens a low-temperature route to realize the fabrication of nanocrystalline MoO2/Mo2CTx heterostructures, leading to achieve rapidly activated conversion reaction and extrinsic pseudocapacitive behaviour. Rather than carbon, highly conductive Mo2CTx decreases the charge transfer resistance in MoO2 and maintains its structural stability upon lithiation/delithiation, ensuring the heterostructures with excellent cyclability (e.g., up to 833 mA h g⁻1 at 100 mA g⁻1 for 160 cycles with 95% capacity retention) and high rate capability (e.g., 665 mA h g⁻1 at 1 A g⁻1). Additionally, owing to the carbon-free characteristic, the secondary nano/microstructure feature and the suppressed surface oxidation trait, MoO2/Mo2CTx heterostructures, therefore, can deliver an improved initial Coulombic efficiency (e.g., up to 78% at 100 mA g⁻1). The present oxycarbide transformation and hybridization strategies are facile but effective, and they are very promising to be applied to converting other oxides–carbon composites into oxides/carbides heterostructures towards achieving higher electrochemical performance.