LaNiO3/NiO hollow nanofibers with mesoporous wall: a significant improvement in NiO electrodes for supercapacitors

Different molar ratios of La:Ni (LaNiO3/NiO) hollow nanofibers were prepared by electrospinning method. The morphologies and microstructures of the samples were examined by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The electrochemical properties of nanofibers were investigated by cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopy (EIS) analyses in an aqueous electrolyte (7 M KOH). Results showed that adding the conductive material (LNO) can enhance the specific capacitance and electrochemical stability of the NiO nanofibers. In particular, La:Ni = 1:2 (LNO:NiO = 1:1) showed a remarkable specific capacitance of 257.8 F g(-1) scaled to the total mass of the electrode or 942 F g(-1) scaled to the active mass (NiO) at a current density of 0.5 A g(-1). The cycling tests operated at a potential window of 0 to 0.45 V with a current density of 0.5 A g(-1) suggested that the electrode had excellent cycling performance, with only 10 % capacitance loss after 1000 cycles.