Construction of an Ultra‐High‐Energy Density Hybrid Supercapacitor with Self‐Assembled 3D Hydrangea Flower‐like Mo‐rich CoMoO₄ Microstructures

Abstract

The accumulation of two-dimensional nanoflakelike units into three-dimensional (3D) hierarchical mesoporous flower-like microstructures can introduce abundant electroactive surface sites and large contact areas with the electrolyte and enable fast ion/electron transport during the electrochemical process. We propose a simple method of constructing a 3D hydrangea flower-like mesoporous Mo-rich CoMoO 4 (CMO) electrode via the solvothermal route (CMO-ETH) with excellent electrochemical characteristics. This morphology arises from the self-assembly of primary nano-particles into flake-like units, then transformed into hydrangea flower-like microstructures. Compared with the CMO-DIW battery-type electrode (hydrothermally synthesized electrode), the CMO-ETH had a higher specific capacity of 678 C g À 1 at a current density of 1 A g À 1 . The fabricated CMO-ETH//activated carbon hybrid supercapacitor (HSC) exhibited an ultra-high energy density of 103.4 Wh kg À 1 at a power density of 750.5 W kg À 1 . We also successfully turned on the red and green LEDs for 3 minutes after connecting two HSCs in series.

Investigation of Zn-to-Co Chemometric Ratio in Zinc Cobaltite Spinel as Battery-Type Superior Redox-Active Electrodes for Hybrid Supercapacitors: Density Functional Theory Analysis

“…Thus, the resulting shift in the peak potentials is illustrated in the figure. The variation in the electrode polarization behavior during CV testing is likely responsible for this phenomenon, and it closely correlates with the chemical composition and physical morphology of the electrode materials Figure S11a–d presents the CV curves of four ZCO electrodes at various scan rates.…”

“…In Figure i–l, an image and concise illustration are presented to showcase the practical viability of the ZCO 1.5–4//AC HSC device. In this experimental setup, two HSC devices are connected in series, successfully powering a dome-topped 5 mm diameter red/green LED indicator at 2 V and 20 mA for a duration exceeding 4 min This demonstration underscores the device’s exceptional prowess as an energy storage solution.…”

“…Among them, ZCO 2.0–4 has a lower flower size. The four samples’ high-magnified images suggest the smaller nanoparticles’ self-assembly formation from petal-like to flower-like morphology during the microwave-assisted hydrothermal reaction …”

“…With the rise of the scan rate, all electrodes’ cathodic and anodic peaks shifted toward the negative and positive potential directions, respectively. This is because of the internal resistance and polarization effects throughout the reversible faradaic process . Nevertheless, it is worth noting that these shifts were relatively minor, indicating the favorable reversibility and rapid charge/discharge response of all ZCO electrodes.…”

“…Moreover, the total current contribution of the ZCO electrodes was determined using eqs s3 and s4 Figure a visually illustrates this relationship between the variables and helps to calculate these values using the above equations.…”