<p>Tungsten oxides with oxygen vacancies, particularly W₁₈O₄₉, hold promise for pseudocapacitive energy storage but are often limited by moderate conductivity and insufficient structural stability under high-rate operation. In this work, a Ni-doped W₁₈O₄₉ electrode with an urchin-like architecture directly grown on nickel foam (Ni-W₁₈O₄₉/NF) is reported via a one-step solvothermal method. This unique interconnected microsphere morphology provides abundant active sites, facilitates electrolyte penetration, and ensures efficient charge transport. The capacitive behaviors of Ni-W₁₈O₄₉/NF electrode in different electrolytes were compared and screened. As a result, when evaluated in 1&#xa0;M AlCl₃ electrolyte, the electrode delivers a specific capacitance of 625 mF cm^− 2 at a high current density of 20&#xa0;mA cm^− 2. Moreover, it exhibits a high Coulombic efficiency of 99.76% and excellent capacitance retention of 99.33% after 3000 cycles at 15&#xa0;mA·cm^− 2. This is confirmed to be attributed to the pseudo-capacitance contribution generated by the smaller Al³⁺ diameter embedded in the Ni-W₁₈O₄₉ lattice. The doped Ni element extends the diameters of these tunnels and generates additional potential defects, thereby providing more sites for the incorporation of Al³⁺. This work provides a scalable design strategy for durable, high-rate supercapacitor electrodes by combining transition-metal doping, oxygen-defect engineering, and electrolyte design.</p>