<p>The advancement of high-performance supercapacitors is dependent upon the development of sustainable and flexible electrode materials. In this work, Ni-doped CeO₂@chitosan (Ni–CeO₂@CS) hybrid framework was synthesized via a simple co-precipitation–hybridization approach. X-ray diffraction (XRD) investigation confirmed the cubic fluorite structure of CeO₂ and exhibited lattice contraction due to Ni doping. Scanning Electron Microscopy (SEM) and transmission electron microscopy (TEM) images confirmed nanosized Ni–CeO₂ particles (8–12&#xa0;nm) homogeneously distributed on the chitosan scaffold and suppressing agglomeration and offering abundant ion-accessible channels. Brunauer–Emmett–Teller (BET) measurements showed a significant increase in surface area from 42 m²&#xa0;g⁻¹ (CeO₂) to 152 m²&#xa0;g⁻¹ for Ni–CeO₂@CS, accompanied by a hierarchical mesoporous distribution. The Ni–CeO₂@CS electrode demonstrated an outstanding specific capacitance of 780 F g⁻¹ at 1 A g⁻¹, with approximately 83% retention at 10 A g⁻¹ and over 90% capacitance retention after 5000 cycles. With capacitance retention of around 94% under 180° bending, the constructed Ni–CeO₂@CS//AC asymmetric supercapacitor maintains ~31 Wh kg⁻¹ even at 10.5&#xa0;kW&#xa0;kg⁻¹ and provides a high energy density of 65 Wh kg⁻¹ at 800 W kg⁻¹. These findings confirm Ni–CeO₂@CS as a viable option for flexible supercapacitor electrodes by demonstrating how the synergistic combination of Ni doping and chitosan biopolymer offers improved conductivity, hierarchical porosity, and stable redox kinetics.</p> Graphical Abstract <p></p>