Practical Synthesis for N‐doped Carbon Microsphere Coated with Zn_0.76Co_0.24S Nanoparticles towards High‐performance Supercapacitors

Abstract

To meet the market demand for supercapacitors with large capacitance and high stability, we successfully prepared a new type of composit material of NÀ C@Zn 0.76 Co 0.24 S with a hierarchical structure utilizing solvothermal and calcination. The nanostructures and electrochemical properties of the samples were tested and analyzed. By adjusting the mass ratio of the Ndoped carbon microsphere during the process of synthesizing composite materials, a series of comparative materials were obtained. The result of research shows that, when the mass ratio of the N-doped carbon microsphere in the composite was 55 %, the nanocomposite demonstrated excellent specific capacitance (2033.7 F g À 1 at a current density of 1 A g À 1 ) and strong cycle performance (retain 88.4 % after 5000 chargedischarge cycles), far superior to that of the single metal sulfide coating on N-doped carbon microsphere. When assembled into NÀ C@ZCS//AC asymmetric supercapacitor (ASC), the ASC exhibits a large energy density of 79.6 Wh kg À 1 while the power density is 799.7 W kg À 1 , proving the composite materials have positive significance in the application of supercapacitors.