Fe-Based Coordination Polymers as Battery-Type Electrodes in Semi-Solid-State Battery-Supercapacitor Hybrid Devices

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Metal-organic frameworks (MOFs) offer tunable structures for energy storage.
• Iron-based MOFs are promising due to iron's abundance and redox activity.
• Understanding structure-property relationships is crucial for optimizing electrode materials.

Purpose of the Study:

• To synthesize and characterize two novel Fe-based MOFs (FeSC1 and FeSC2) with varying dimensionality.
• To investigate the impact of void space and coordination modes on electrochemical performance.
• To evaluate their potential as battery-type electrodes and in hybrid devices.

Main Methods:

• Solvothermal synthesis of FeSC1 (2D) and FeSC2 (1D) using FeSO4·7H2O, H3TATB, and bib.
• Electrochemical evaluation in three-electrode systems to determine capacities and charge-transfer properties.
• Assembly of semi-solid-state battery-supercapacitor-hybrid (sss-BSH) devices for practical performance assessment.

Main Results:

• Both FeSC1 and FeSC2 exhibited distinct and outstanding electrochemical performances.
• Charge storage was primarily governed by diffusion-controlled processes (i ∝ v^0.5).
• Partial phase transformations to FeOOH occurred during long-term cycling.
• The sss-FeSC1//AC BSH device showed excellent capacitance, energy/power density, and stability.

Conclusions:

• Dimensionality, void space, and coordination modes significantly influence MOF electrochemical behavior.
• Fe-based MOFs show great potential as high-performance electrode materials.
• The developed sss-BSH devices demonstrate practical viability for energy storage.