Bi-metal Sulfides Embedded in MOF-derived N-doped Carbon Polyhedral Nanocages for High-performance Lithium-ion Batteries

Abstract

The high rate and long life performance of the lithium ion batteries are affected by serious volume change and low conductivity of the active electrode material during the charging and discharging. Herein, bimetal sulfides embedded in N-doped carbon polyhedral nanocages (SnS@CoS@NCNTs) are successfully designed by employing porous metal-organic frameworks (MOFs) as precursors. Benefiting from the abundant active sites of metal sulfide, the catalytic properties of CoS, and the high conductivity of porous carbon, SnS@CoS@NCNTs electrode materials exhibit excellent performance. The electrode delivers the initial specific capacity of 1112 mA·h·g−1 and the remarkable capacity of nearly 440 mA·h·g−1 after 300 cycles in current density of 1 A·g−1, which may be caused by the synergistic effect of bimetal sulfides and N-doped carbon polyhedral nanocages to enhance the structural stability and ion/electron conductivity. This work provides a feasible method for constructing bimetal-sulfide/carbon composites with excellent electrochemical performance.