Mesoporous LaNiO3/NiO nanostructured thin films for high-performance supercapacitors

Mesoporous LaNiO3 (LNO)/NiO electrodes for thin film supercapacitors have been developed from a sol–gel precursor using polyethylene glycol 1000 (PEG 1000) as a template. It is the first time that the LNO/NiO thin films have been reported as electrochemical electrodes. Electrochemical measurements in an aqueous electrolyte (1 M Na2SO4) show areal specific capacitances of about 9.5 mF cm−2 and 1.85 mF cm−2 at the scan rates of 0.1 V s−1 and 100 V s−1, respectively. The film shows a quasi-rectangular curve even at the ultrahigh scan-rate of 100 V s−1, which is much higher than that of conventional supercapacitors. The specific capacitance is five orders of magnitude higher than most of the micro-/thin films. The cycling tests operated at the potential window of 0 to 1 V with a current density of 1 mA cm−2 suggest that the thin film electrode has an excellent cycling performance with only 2.8% capacitance loss after 1000 cycles. It is believed that LNO can improve the electrical conductivity and stability of the electrodes, and the porous structure can provide full accessibility of the electrolyte, which is helpful in enhancing the stable performance of the electrochemical behaviors.