Different distribution of in-situ thin carbon layer in hollow cobalt sulfide nanocages and their application for supercapacitors

Recently, cobalt sulfides emerge as a candidate for energy reserve and conversation. However, the problem of poor stability and low rate capability for cobalt sulfides restrict its practical application. Thin carbon layer (TCL) coated has been regarded as a promising constructing strategy for high performance supercapacitors, because TCL can promote the tremendous properties of bare materials. In this literature, we report a very interesting phenomenon that different distribution of in-situ carbon coated hollow CoS2 nanocages (external and both external and interior) can be synthesized only by adjusting sulfuration time, followed by calcination. Moreover, it is clearly observed that CoS2-C@TCL exhibits significant improvement for specific capacitance and good stability (better than CoS2@TCL and CoS2). These results compel us to design a series of experiments to figure out the reason and the more detailed mechanism is discussed in paper. More importantly, it will provide a new strategy for synthesis of special structure with in-situ carbon coated sulfide for energy conversion. (C) 2016 Elsevier B.V. All rights reserved.