Porous engineering of CoS2/N-doped carbon polyhedra anode for durable lithium-ion battery.

In this work, the porous CoS2/N-doped carbon polyhedra (P-CoS2/CP) has been developed by employing ZIF-67 as the template for durable lithium-ion battery anode. The as-prepared P-CoS2/CP exhibits the novel dodecahedron structure filling with nanopores and CoS2 nanoparticles. As compared to CoS2/CP (122 m2 gâˆ'1), the P-CoS2/CP possesses the higher specific surface area of 367 m2 gâˆ'1, which benefits to enlarge the electrode-electrolyte contact area and promote the Li+ diffusion dynamics at high current density. On the other hand, the CoS2 nanoparticles are firmly wrapped by the carbon skeleton which can effectively suppresses the volume expansion of CoS2 during the charging/discharging process. Besides, the N-doping enable to improve the conductivity of CP. As a result, the initial discharge capacity of P-CoS2/CP at 0.1 A gâˆ'1 is 1484.7 mAh gâˆ'1 with the coulombic efficiency of 48.9%. After 100 cycles, the reversible capacity stabilized at 726.2 mAh gâˆ'1. Even the current density increases to 2.0 A gâˆ'1, a high reversible capacity of 353.7 mAh gâˆ'1 can still be achieved, realizing the good rate capability. The superior Li+ performance of P-CoS2/CP is attributed to the synergistic effect of the unique multi-space structure and the high chemical activity of CoS2. Moreover, the Li+ diffusion coefficient of P-CoS2/CP is 4.52 × 10âˆ'6 to 1.98 × 10âˆ'11 cm2 sâˆ'1, which is higher than that of CoS2/CP (1.45 × 10âˆ'9 to 5.23 × 10âˆ'11 cm2 sâˆ'1), highlighting the significance of porous engineering. [ABSTRACT FROM AUTHOR]