Achieving Fast and Stable Lithium/Potassium Storage by In Situ Decorating FeSe₂ Nanodots into Three-Dimensional Hierarchical Porous Carbon Networks

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 FeSe 2 nanodots (FeSe 2 @PCN) for fast and stable lithium/potassium storage. The FeSe 2 @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 FeSe 2 nanodots during lithiation/potassiation to maintain the integrity of electrode materials. Thus, FeSe 2 @PCN displays exceptional electrochemical properties for lithium storage in terms of high capacity (1150 mAh g –1 after 100 cycles at 200 mA g –1 ) and outstanding cyclic stability (232 mAh g –1 after 5000 cycles at 10 A g –1 ). When further used in KIBs, it delivers a superior capacity of 390 mAh g –1 at 100 mA g –1 and retains 128 mAh g –1 after 500 cycles at 2 A g –1 .