Bottom‐up Approach for Designing Cobalt Tungstate Nanospheres through Sulfur Amendment for High‐Performance Hybrid Supercapacitors. Issue 6 (17th February 2021) - Patil, Swati J.
Abstract: Nanofabrication of heteroatom‐doped metal oxides into a well‐defined architecture via a "bottom‐up" approach is crucial to overcome the boundaries of the metal oxides for energy storage systems. In the present work, this issue was addressed by developing sulfur‐doped bimetallic cobalt tungstate (CoWO4 ) porous nanospheres for efficient hybrid supercapacitors via a single‐step, ascendable bottom‐up approach. The combined experimental and kinetics studies revealed enhanced electrical conductivity, porosity, and openness for ion migration after amendments of the CoWO4 via sulfur doping. As a result, the sulfur‐doped CoWO4 nanospheres exhibited a specific capacity of 248.5 mA h g −1 with outstanding rate capability and cycling stability. The assembled hybrid supercapacitor cell with sulfur‐doped CoWO4 nanospheres and activated carbon electrodes could be driven reversibly in a voltage of 1.6 V and exhibited a specific capacitance of 177.25 F g −1 calculated at 1.33 A g −1 with a specific energy of 63.41 Wh kg −1 at 1000 W kg −1 specific power. In addition, the hybrid supercapacitor delivered 94.85 % initial capacitance over 10000 charge‐discharge cycles. The excellent supercapacitive performance of sulfur‐doped CoWO4 nanospheres may be credited to the sulfur doping and bottom‐up fabrication of the electrode materials. Abstract : Sulfur‐modified CoWO4 nanospheres designed via a single‐step "bottom‐up" approach prove superior redox chemistry. The hybrid supercapacitor assembled with S−CoWO4 cathode demonstrates the high‐energy storing capacity with long‐term stability that might be useful in real energy storage applications.