Dextran stabilised hematite: a sustainable anode in aqueous electrolytes

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Hybrid materials offer advances in energy storage but face challenges like material solubility and poor conductivity.
• Electrode materials and electrolytes significantly impact electrochemical performance in energy storage devices.

Purpose of the Study:

• To fabricate novel, sustainable anode electrodes for energy storage using cross-linked oxidized dextran (Ox-Dex) as a binder and hematite (α-Fe2O3) cubes as the active component.
• To investigate the ion diffusion mechanism and cycling stability of these hybrid electrodes in various aqueous electrolytes (Li+, Zn2+, Al3+).

Main Methods:

• Fabrication of hybrid anode electrodes using oxidized dextran (Ox-Dex) and hematite (α-Fe2O3).
• Electrochemical performance evaluation using cyclic voltammetry in Li2SO4, ZnSO4, and Al2(SO4)3 aqueous electrolytes.
• Analysis of ion diffusion mechanisms and cycling stability.

Main Results:

• Hybrid iron oxide electrodes demonstrated high electrochemical performance, with capacities of 3000 mA g-1 in Al2(SO4)3, 2000 mA g-1 in ZnSO4, and 800 mA g-1 in Li2SO4.
• Superior cycling stability was observed for hybrid anodes (1.3% variance) compared to bare electrodes (38.1% variance) in Zn2+ electrolytes, attributed to the natural binder.
• The highest ion diffusion coefficient (4.64 × 10-9 cm2 s-1) was achieved in the Al3+ electrolyte, linked to ionic radii.

Conclusions:

• The proposed hybrid electrodes, utilizing cross-linked Ox-Dex and hematite, show significant potential for high-performance and sustainable energy storage.
• The natural binder (Ox-Dex) enhances electrode stability and tolerance to volume changes through hydrogen bonding interactions.
• Optimized ion diffusion and structural integrity make these hybrid anodes promising for next-generation energy storage devices.