Hydroxyethyl Cellulose-Intercalated Vanadium Oxide Cathodes with Lattice Defect Engineering for High-Performance...

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Aqueous zinc-ion batteries (AZIBs) face challenges with cathode structural instability and capacity fading.
• Developing stable and high-performance cathodes is crucial for advancing AZIB technology.

Purpose of the Study:

• To fabricate a novel composite cathode material, VO-i-HEC, for AZIBs.
• To address the limitations of structural instability and capacity fading in vanadium pentoxide (V2O5) cathodes.
• To investigate the synergistic effects of hydroxyethyl cellulose (HEC) intercalation on V2O5 structure and electrochemical performance.

Main Methods:

• Fabrication of VO-i-HEC composite by intercalating HEC into V2O5.
• Characterization of structural modifications, including interlayer spacing expansion and defect introduction.
• Electrochemical testing to evaluate specific capacity, rate capability, and cycling stability.
• Computational analysis using differential charge density and density functional theory (DFT) to understand ion diffusion and reaction mechanisms.

Main Results:

• HEC intercalation expanded V2O5 interlayer spacing to 12.74 Å and introduced lattice defects.
• The modified cathode (VO-i-HEC) exhibited a high specific capacity of 499.88 mAh·g⁻¹ at 0.1 A·g⁻¹.
• Remarkable cycling stability was achieved with over 2000 cycles at 10 A·g⁻¹ and a low capacity decay rate of 0.004%.
• DFT calculations confirmed reduced Zn²⁺ migration barriers (0.14 eV) and suppressed parasitic reactions.

Conclusions:

• The structure-interface synergistic regulation strategy using HEC intercalation is highly effective for vanadium-based cathodes in AZIBs.
• VO-i-HEC demonstrates superior electrochemical performance, including high capacity and excellent stability.
• This approach provides a viable design paradigm for developing high-performance AZIBs.