Highly Energetic and Stable Gadolinium/Bismuth Molybdate with a Fast Reactive Species, Redox Mechanism of Aqueous Electrolyte

The electronic properties and stability of gadolinium-doped bismuth molybdate composites are critical characteristics that determine the efficiency of storing energy reversibly as a propitious electrode for energy storage applications. Gd-doped Bi2MoO6 is presented, which is based on the orthorhombic phase host Bi2MoO6 lattice, where variable amounts of Gd dopant are substituted in the Bi site, resulting in significantly improved energy storage performance. The doping effects with the aim of better understanding the electronic structure of Gd-doped Bi2MoO6 and fine-tuning the properties of energetically favorable material that possesses the most stable crystal structure are reported. The measured X-ray photoelectron spectra of Gd (4d) confirm the presence of the Gd(III) state. The enhanced stability of Gd0.05Bi1.95MoO6 has been attributed to the ability to distribute electron density evenly. In a three-electrode configuration, using aqueous NaOH electrolyte, the Gd0.05Bi1.95MoO6 electrode demonstrated a high specific areal capacitance of 2.15 F cm–2 (the equivalent of 191.5 mAh g–1). The results reported herein are important as they provide an insight into the factors influencing highly energetic and fast reactive species in the Gd(III) composites, which could be a potential anode material for energy storage applications. The optimized anode material is coupled with Ni–Co–Cu ternary oxide cathode and evaluated as a device. The asymmetric supercapattery showed 153 mAh g–1 at a current density of 4 mA cm–2 with an excellent retention of 89% after 1000 long cycles.