Dual-cations modulating δ-MnO₂ as a high-performance cathode material for aqueous zinc-ion batteries.

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Delta-manganese dioxide (δ-MnO₂) is a promising cathode material for aqueous zinc-ion batteries (AZIBs) due to its high capacity, low cost, and environmental friendliness.
• However, its practical use is limited by poor electronic conductivity and structural instability.

Purpose of the Study:

• To synthesize and characterize Fe&Co dual-cations doped δ-MnO₂ (FCMO) for enhanced AZIB performance.
• To investigate the effects of dual-cations doping on the crystal structure, morphology, and electrochemical properties of δ-MnO₂.

Main Methods:

• Facile hydrothermal synthesis route for Fe&Co dual-cations doping of δ-MnO₂.
• Morphological and structural characterization using techniques such as electron microscopy and X-ray diffraction.
• Electrochemical performance evaluation including specific capacity, rate capability, and cycling stability in AZIBs.

Main Results:

• Nanoflower-like FCMO morphology was achieved, shortening ion diffusion paths.
• Dual-cations doping introduced oxygen vacancies, enhancing electronic conductivity and structural stability.
• Expanded interlayer spacing improved Zn²⁺ diffusion kinetics, resulting in high specific capacity (319.9 mAh·g^-1 at 0.5 A·g^-1), excellent rate performance (100.1 mAh·g^-1 at 2 A·g^-1), and outstanding cycling stability (94.7% retention after 1000 cycles).

Conclusions:

• Fe&Co dual-cations doping is an effective strategy to significantly enhance the electrochemical performance of δ-MnO₂ for AZIBs.
• The developed FCMO material offers a promising cathode for high-performance and stable aqueous zinc-ion batteries.