A Parchment‐Like Supercapacitor Made with Sustainable Graphene Electrodes and its Enhanced Capacitance by Incorporation of the LaSrCoO3 Perovskite

Abstract

AbstractThis work reports the electrochemical properties of rollable supercapacitors (SCs) assembled with electrodes made of recycled soda label as supporting substrate, graphene (conductive material), TiNi alloy (negative collector) and copper foil (positive collector). The electrochemical properties of the SCs improved by adding the La0.5Sr0.5CoO3 (LSC) nanoparticles on their electrodes. Those nanoparticles have irregular morphology and sizes of 220–1800 nm. The SCs fabricated without LSC exhibited a gravimetric capacitance and energy density of 406.3 F g−1 and 56.5 Wh kg−1, respectively. When the LSC is added on the SC electrodes, the above values increase to 920.9 F g−1 and 127.1 Wh kg−1, that is, the capacitance was enhanced by ≈84 %. Another SC was fabricated using copper foil as negative collector instead of the TiNi alloy, but the capacitance and energy density were lowered to 135 F g−1 and 18.7 Wh kg−1, respectively. This result indicates that using the TiNi alloy as negative collector was important to produce higher capacitance. Surprisingly, the capacitance retention of the SC made with LSC increased to 133 % after 300 rolling cycles but it diminished to 78 % after 500 rolling cycles. The devices made with and without LSC exhibited output voltages of 1.25 V and 0.4 V, respectively. UV‐Vis absorbance, Raman and XPS spectra revealed the existence of oxygen vacancy defects and Co2+/Co3+ species on the SC electrodes, which worked as redox centers for the charge storage.