Cerium oxide-loaded poly(lactic acid)-poly(butylene adipate terephthalate) composite membranes: Preparation and energy storage performance in supercapacitors

The present study demonstrated the successful fabrication of high-performance supercapacitor electrodes on the basis of cerium oxide (CeO 2 ), reinforced poly(lactic acid) (PLA), poly(butylene adipate terephthalate) (PBAT) composite films with different CeO 2 loadings (0.25, 0.50, 0.75, and 1.00 wt%) and fully characterized their physicochemical and electrochemical properties. The 0.50 wt% CeO 2 -loaded composite revealed the best compromise between the capacity to store energy and the ability to deliver power. At a current density of 3.0 A g −1 , this electrode was capable of yielding a remarkably high specific capacitance of 264 F g⁻¹, coupled with impressive values for energy density (146.67 Wh kg⁻¹) and power density (12,000 W kg⁻¹). In all cases, the specific capacitance was found to decrease progressively with the scanning rate, which is a typical behavior attributable to the extra time required for ion migration through the electrolyte at fast charging, discharging cycles. The electrode with 0.50 wt% CeO 2 @PLA, PBAT, in particular, displayed outstanding capacitive properties as evidenced by the near-ideal linearity and symmetry of the charge, discharge curves, excellent coulombic efficiency, and cycling stability, which in terms of quantitative retention was ca. 84% of the initial capacitance after 4000 continuous cycles of charging and discharging. It was implied that the synergistic combination of the characteristics of CeO 2 and the biodegradable polymer matrix can provide a multifunctional, efficient, and hence, sustainable, green energy electrode material with little negative impact on the environment and people.