Fe−Ni with Chitosan via Microwave and Carboxymethyl as Electrode Materials for Supercapacitor

Abstract Iron‐nickel double hydroxides (Fe−Ni) have been broadly synthesized for supercapacitors (SC). However, the influence of precipitant quantity on SC performance is one of the present challenges. Herein, we found that Fe_0.64Ni_0.36@ graphite electrodes, the open and interconnected 3D graded conductive network of carboxymethyl chitosan‐derived porous carbon (C), have achieved effective surface contact. In addition, iron and nickel reinforced redox active materials on porous carbon will undergo more redox reactions for rapid diffusion of electrolyte ions/electrons. Due to the special construction and the synergistic effect of multiple oxidation transformations, the prepared Fe_0.64Ni_0.36@graphite composite material exhibits a maximum capacitance of 1232 F g⁻¹ at a current density of 1 A g⁻¹. The prepared Fe_0.64Ni_0.36@graphite//Fe_0.64Ni_0.36@graphite symmetric supercapacitors exhibit a high energy density of 22.9 Wh kg⁻¹ at a power density of 771 W kg⁻¹. Particularly, the sample exhibits excellent cycling stability, retaining approximately 95.8 % capacitance after 5000 cycles.