Robust cyclic stability and high-power performance of Ni/Mg co-doped CeO2 electrodes for asymmetric hybrid supercapacitors

Ceria co-doped with Ni and Mg (Ni, Mg@CeO 2 ) was examined for its electrochemical performance, showing impressive power density and cyclic stability in the fabricated device. The material was synthesized using an easy, low-cost solution combustion method. Two different materials were studied to evaluate the impact of co-doping: pristine CeO 2 /AC (M − 1) and Ni, Mg@CeO 2 composite with AC (Activated Carbon) (M − 2). Structural analysis confirmed the face-centered cubic (FCC) structure of CeO 2 through X-ray diffractometry (XRD). The structural and optical properties were characterized by using field-emission scanning electron microscopy (FESEM) and photoluminescence (PL) spectroscopy, respectively. The electrochemical behavior was tested with cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopy (EIS), revealing the pseudocapacitive nature of the ceria-based electrodes. As an electrode material, CeO 2 /AC (M − 1) achieved a higher specific capacitance (C s ) of 244.4 F/g at 0.5 A/g, while Ni, Mg@CeO 2 /AC (M − 2) showed 197.6 F/g at the same current. In a full-device setup, Ni, Mg@CeO 2 //AC (M − 2) reached a C s of 63.3 F/g at 0.5 A/g, along with excellent cycling stability, retaining 100.4 % coulombic efficiency over 5000 GCD cycles. The hybrid device based on Ni, Mg@CeO 2 //AC displayed a maximum specific energy of 18.3 Wh/kg and a specific power of 467.5 W/kg at 0.5 A/g. • Facile & scalable solution combustion Synthesis of Ni,Mg co-doped CeO 2 . • Porous spherical morphology provides a high surface-to-volume ratio, enhancing active sites for charge storage. • Delivers Outstanding 124.5 F/g capacitance with excellent cycling stability, showing 100.4 % retention after 5000 cycles. • High energy & power density 36.36 Wh/kg & 935 W/kg, respectively as trademark competitive for supercapacitor applications. • Synergistic doping effect of Ni,Mg in CeO 2 optimizes electronic structure, boosting conductivity and redox activity.