Hollow Cobalt Selenide-Carbon polyhedron sandwiched between reduced graphene oxide nanosheets: A superior anode material for lithium-ion batteries

Abstract

In this work, a double carbon-confined sandwich-like CoSe/NCP/rGO composite was fabricated using an self-assembled method combined with a selenization treatment. In the composite, cobalt selenide (CoSe) nanoparticles were embedded in N‑doped hollow carbon polyhedrons (NCP) and sandwiched between reduced graphene oxide (rGO) nanosheets. The kinetics of electron/ion transport along with the structural stability of the composite were significantly enhanced by the layer-by-layer sandwiched hollow structure and the strong cohesive interface interaction between various components. The CoSe/NCP/rGO, when serving as LIB’s anode material, exhibited excellent performance. It demonstrated a high specific capacity with the value of 843 mAh/g at 1 A/g, superior high-rate capability with capacity remaining at 309 mAh/g at 10 A/g, long-term cycling stability with no noticeable capability fading over 1000 loops. More importantly, these results were achieved without additional conductive agents.