Organic-Inorganic Coupling Strategy: Clamp Effect to Capture Mg²⁺ for Aqueous Magnesium Ion Capacitor

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Rapid transport of divalent magnesium ions (Mg2+) is essential for high-performance aqueous magnesium-ion battery energy storage capacitors.
• The strong electrostatic interaction between Mg2+ and host materials hinders Mg2+ diffusion, limiting battery performance.
• Developing advanced electrode materials is crucial to overcome these limitations.

Purpose of the Study:

• To synthesize a novel composite material, EDA-Mn2O3, for enhanced aqueous magnesium-ion capacitor performance.
• To investigate the synergistic effects of organic (ethylenediamine, EDA) and inorganic (manganese sesquioxide, Mn2O3) phases on energy storage mechanisms.
• To explore the practical application value of organic-inorganic composite electrodes with double-energy storage mechanisms.

Main Methods:

• Synthesis of EDA-Mn2O3 composite via an organic-inorganic coupling strategy.
• Characterization using density functional theory (DFT) calculations, ex situ X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy.
• Electrochemical performance testing of the composite as a cathode material in aqueous magnesium ion capacitors.

Main Results:

• The EDA-Mn2O3 composite exhibits a specific discharge capacity of 188.97 mAh/g at 0.1 A/g.
• The composite-based aqueous magnesium ion capacitor achieves an energy density of 110.17 Wh/kg.
• DFT, ex situ XRD, XPS, and Raman analyses confirmed the synergistic effects and enhanced Mg2+ intercalation/deintercalation.

Conclusions:

• The synthesized EDA-Mn2O3 composite demonstrates excellent performance for aqueous magnesium-ion capacitors.
• The synergistic organic-inorganic structure effectively enhances Mg2+ transport and storage capacity.
• This study highlights the potential of organic-inorganic composites for advanced energy storage applications.