Rational design and fabrication of one-dimensional hollow cuboid-like FeMoO₄ architecture as a high performance electrode for hybrid supercapacitor

The design and progress of extremely efficient electroactive electrode materials with nano-dimensional architecture are the recent focus of hybrid supercapacitors (HSCs). In particular, the one-dimensional hollow micro-/nanostructures have fascinated wide attention in the next generation energy storage materials due to their unique charge transport and storage properties. Herein, we report a facile fabrication of one-dimensional hollow cuboid-like FeMoO₄ (FMO) micro-/nanostructures through a simple hydrothermal approach. Further, the as-prepared FeMoO₄ (AFMO) and the calcined FeMoO₄ (CFMO) materials were comparatively studied to ensure the electrochemical property of the materials. The unique one-dimension hollow cuboid-like architecture facilitates shorten and fast transportation route of charges to decrease the capacitance fading. Further, the extra void space of the CFMO sample due to the calcination process could facilitate easy access for electrolyte ion diffusion within the interior of the electrode materials, thus shortening the electrolyte's diffusion resistance. Besides, the well-ordered structural stability of the CFMO electrodes could improve the rate capability and cyclic durability, which is apparent in the excellent long-term stability of the HSC. Thus, the CFMO micro-/nanostructures exhibit good electrochemical performance with a maximum specific capacitance (C_sp) of 493 F g⁻¹ at a current density of 1 A g⁻¹, which is superior to the AFMO materials (332 F g⁻¹ at the same current density of 1 A g⁻¹). Moreover, the constructed HSC (CFMO//AC) exhibits a maximum C_sp of 96 F g⁻¹ and also offers a maximum energy density (ED) of 29.89 W h kg⁻¹ at a power density (PD) of 1001.58 W kg⁻¹. In addition, the HSC exhibits excellent long-term cyclic life with 89.62% capacitance retention over 10,000 repeated charge/discharge cycles.