Boosting lithium storage in silicon anodes by synergistic dual carbon confinement and CoSe 2 / CoO heterostructures

Abstract The significant volume expansion and poor conductivity of Si anodes hinder their applications. In this work, a hierarchical double carbon shell embedded with CoSe 2 /CoO heterostructures derived from Co‐based zeolitic imidazolate framework (ZIF‐67) and polydopamine (PDA) was coated on Si nanoparticles (Si@CN‐CoSeO@NC). The double shell not only improves electrical conductivity and alleviates volume changes but also establishes a built‐in electric field at the CoSe 2 /CoO interface, enabling efficient charge transfer and enhanced reaction kinetics. Benefiting from the synergies between compositional and structural advantages, the Si@CN‐CoSeO@NC anode delivered high reversible capacity and superior cycling stability, retaining 1198 mA h g −1 after 500 cycles at 1 A g −1 and 538.7 mA h g −1 after 1000 cycles at 5 A g −1 . Furthermore, a full cell coupled with a LiFePO 4 cathode exhibited a high specific capacity of 127.8 mAh g −1 after 100 cycles at 1.2 C.