Suitable Morphology Makes CoSn(OH)6 Nanostructure a Superior Electrochemical Pseudocapacitor

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Material morphology critically influences catalytic reaction rates and electrochemical device performance.
• Developing stable aqueous asymmetric supercapacitors (AAS) with high energy density without compromising power density is crucial.
• Cobalt tin hydroxide (CoSn(OH)6) presents potential as a metal hydroxide electrode material for supercapacitors.

Purpose of the Study:

• To investigate the impact of altered morphology of CoSn(OH)6 nanomaterials on supercapacitor performance.
• To synthesize and characterize hierarchical mesoporous nanostructured (HNS) and cubic nanostructured (CNS) CoSn(OH)6.
• To fabricate and evaluate an aqueous asymmetric supercapacitor (AAS) using optimized CoSn(OH)6 morphology.

Main Methods:

• Synthesis of hierarchical mesoporous nanostructured (HNS) CoSn(OH)6 using ammonia as a hydrolyzing agent.
• Transformation of HNS into cubic nanostructured (CNS) CoSn(OH)6 using NaOH solution, acting as structure-directing and etching agent.
• Fabrication of pseudocapacitor electrodes using both HNS and CNS CoSn(OH)6 in KOH electrolyte.
• Assembly of an aqueous asymmetric supercapacitor (AAS) using HNS CoSn(OH)6 as the positive electrode and activated carbon (AC) as the negative electrode.

Main Results:

• The HNS CoSn(OH)6 electrode exhibited a significantly higher specific capacitance (2545 F/g at 2.5 A/g) and better cyclic durability compared to the CNS CoSn(OH)6 electrode (851 F/g at 2.5 A/g).
• The fabricated AAS device using HNS CoSn(OH)6//AC demonstrated a high specific capacitance of 713 F/g at 1.5 A/g.
• The AAS device retained 92% of its specific capacitance after 10,000 charge-discharge cycles, achieving a maximum energy density of 63.5 Wh/kg and a maximum power density of 5277 W/kg.

Conclusions:

• Altered morphology of CoSn(OH)6, specifically the hierarchical mesoporous nanostructure (HNS), is critical for enhancing supercapacitor performance.
• The HNS CoSn(OH)6//AC aqueous asymmetric supercapacitor offers excellent capacitance, stability, and high energy and power densities.
• This study highlights the potential of morphologically controlled CoSn(OH)6 nanomaterials for advanced energy storage applications.