Heterogeneous atoms mediated formation MnCo2S4/PNG heterostructures for high-performance supercapacitors

Transition metal sulfides are considered as potential electrode materials for high performance energy storage devices. However, structural instability during electrochemical reactions has seriously hindered their wide applications. In this study, we demonstrate that MnCo2S4/PNG (N- and P-doped graphene) composite constructed with hetero-atomic induction exhibits excellent morphological stability. Heterogeneous atoms doping on graphene can change its surface charge distribution. Under the induced effect of surface charge, the crystal growth and assembly process of MnCo2S4 nanostructure are changed as well, which leads to MnCo2S4 nanoparticles (NPs) uniformly anchored on the curled and folded PNG layer. In this case, it avoids the agglomeration of MnCo2S4 NPs, and thus increasing the specific surface area and pore volume of the composite, which is conducive to the full contact between the electrode and the electrolyte and therefore the rapid diffusion rate of the electrolyte ions at the interfaces. The obtained 1.4MnCo(2)S(4)/PNG material has a specific capacitance of 2465 F g(-1) at 1 A g(-1). In addition, the electrode possesses high conductivity, excellent rate performance and cyclic stability. The assembled 1.4MnCo(2)S(4)/PNG//PNG asymmetric supercapacitor yields an energy density of up to 65.1 Wh kg(-1) under the power density of 800 W kg(-1), showing excellent energy storage characteristics.