Novel anode materials are of paramount significance for the development of advanced Li- and K-ions batteries with high energy density, favorable rate capability, and long lifespan. We herein construct a delicate three-dimensional (3D) hierarchical porous carbon networks uniformly decorated with FeSe2nanodots (FeSe2@PCN) for fast and stable lithium/potassium storage. The FeSe2@PCN features a honeycomb-like architecture made up of countless cross-linked N-doped carbon membranes, which is synthesized via a simple and scalable gas-pumped self-expanding approach. The well-integrated porous carbon network (PCN) matrix not only can facilitate ion/electron transportation and offer sufficient active sites for Li+/K+adsorption but also accommodate the volumetric change of decorated FeSe2nanodots during lithiation/potassiation to maintain the integrity of electrode materials. Thus, FeSe2@PCN displays exceptional electrochemical properties for lithium storage in terms of high capacity (1150 mAh g–1after 100 cycles at 200 mA g–1) and outstanding cyclic stability (232 mAh g–1after 5000 cycles at 10 A g–1). When further used in KIBs, it delivers a superior capacity of 390 mAh g–1at 100 mA g–1and retains 128 mAh g–1after 500 cycles at 2 A g–1.