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 FeSe2 nanodots (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 gaspumped 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 FeSe2 nanodots 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(-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 after 500 cycles at 2 A g(-1).