Herein we report a novel facile strategy for the fabrication of Co3O4 porous nanocages based on the Kirkendall effect, which involves the thermal decomposition of Prussian blue analogue (PBA) Co3[Co(CN)6]2 truncated nanocubes at 400 °C. Owing to the volume loss and release of internally generated CO2 and NxOy in the process of interdiffusion, Co3O4 nanocages with porous shells and containing nanoparticles were finally obtained. When evaluated as electrode materials for lithium-ion batteries, the as-prepared Co3O4 porous nanocages displayed superior battery performance. Most importantly, capacities of up to 1465 mA h g−1 are attained after 50 cycles at a current density of 300 mA g−1. Moreover, this simple synthetic strategy is potentially competitive for scaling-up industrial production.