The nanoglasses embedded NiCo2O4 nanocomposite induced by S interstitial doping for supercapacitor electrodes

Abstract

The nanoglasses embedded NiCo2O4 on Ni foam induced by the S interstitial doping (S-NCO@NF) is achieved in this work. Attributed to the interconnected nanostructure, the generation of nanoglasses as well as the S doping, the obtained S-NCO@NF electrode demonstrates strong OH– adsorption capability and excellent electrochemical performances. Moreover, the derivation of NiCo2O4 nanoglasses was studied by DFT calculations. The insertion of S atoms into NiCo2O4 crystal induces the dramatic relative atomic displacement and thus results in the generation of nanoglasses with many unsaturated atoms and tremendous dangling bonds. Such unique atomic structure and S doping endow the S interstitial doped models with remarkable OH– adsorption capability. Notably, the OH– adsorption calculations reveal that the doped S atoms also take part in redox reactions and perform as active sites, providing a new insight into the nonmetal doped models. The S-NCO@NF electrode demonstrates high capacitance, remarkable rate capacity and excellent cycle stability (84.44% retention after 6000 cycles). This current paper undoubtedly provides a new perspective for describing the enhancement effect of doping atoms on electrode performance.