Lanthanum-doped rGO from biomass: a sustainable electrode material for enhanced supercapacitor performance

Abstract We report the electrochemical performance of supercapacitor electrodes made from lanthanum (La 2 O 3 )-imbued biomass-based reduced graphene oxide (rGO) composites. Integration of lanthanum at various contents (0, 0.25, 0.5, 0.75, and 1 g) with rGO was observed to appreciably improve the specific capacitance, electrical conductivity, and impedance characteristics of the novel composites. The composite made with 0.5 g of La 2 O 3 (rGO-La_0.5) achieved a very high specific capacitance value of 67.32 F g −1 at a current of 2 mA, indicating its remarkable energy storage capability. The studied composites’ resistance decreased from 3.01 to 1.52 Ω, suggesting an enhanced charge transfer and reduced diffusion impedance mechanism. XRD analysis confirmed an optimization of rGO crystal structure due to La 2 O 3 inclusion, leading to more atomic ordering and better charge flow than the pristine composite (rGO-La_0). FESEM micrographs of the composites disclosed successful doping of lanthanum particles into the rGO sheets, preventing its restacking and increased ion adsorption. Furthermore, the pore size distribution of the composites exhibited their mesoporous nature, enabling rapid ion transfer that was meritorious for energy retention. It is asserted that the proposed La 2 O 3 -doped rGO composites as supercapacitor electrodes can be beneficial for advanced energy storage applications, thus contributing to sustainable solutions. However, optimizing La 2 O 3 contents in composites and assessing the long-term stability of the designed composite-based electrodes for practical energy storage use is worthy of study.