3D Porous CoS2 Hexadecahedron Derived from MOC towards Ultrafast and Long-Lifespan Lithium Storage

In this work, a novel hexadecahedron assembled by core-shell CoS2 particles@N-doped carbon (CoS2@NCH) is successfully prepared via the self-template method. The CoS2@NCH hybrid electrode delivers a high lithium-storage capacity of 778 mA h g-1 after 1000 cycles at a high current density of 1 A g-1, which is the longest cycle lifespan among the reported CoS2 anode materials in lithium ion batteries. Furthermore, CoS2@NCH hybrid electrode shows excellent rate capability with the discharge capacity of 220 mA h g-1 at extremely high current density of 20 A g-1 and a charge capacity of 649 mA h g-1 is restored when current density is back to 2 A g-1. The superior performance is attributed to unique construction of CoS2@NCH. The N-doped interconnected porous carbon shells formed highly conductive skeletons for the quick electron transfer when prevent the electrode from collapsing. Moreover, porous characteristic of the materials play a key role: as some effective channels, the mesopores on porous carbon shells provide more accesses for lithium, while the mesopores derived from inter-space of particles can immerse electrodes in electrolyte completely that alleviate the volume expansion and ensure the integrity of the electrode. In addition, the nano-sized CoS2 particles which shorten the ion transport path and provide extra electroactive sites also improve the reaction kinetics.