π-π Stacking-Assisted Self-Assembly Fabricates Highly Uniform PANI@RGO Cathodes Toward High-Performance Aqueous...

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Polyaniline (PANI) is a promising cathode material for aqueous zinc-ion batteries (AZIBs) due to its rapid redox kinetics and environmental friendliness.
• However, PANI's practical application is hindered by morphological aggregation and low specific surface area, limiting battery performance.

Purpose of the Study:

• To develop a novel solvent-mediated self-assembly strategy for creating uniform, high-surface-area PANI/reduced graphene oxide (PANI@RGO) composite gels.
• To investigate the impact of this strategy on the electrochemical performance of AZIBs, particularly focusing on high PANI content and improved structural properties.

Main Methods:

• Employed an N-methyl-2-pyrrolidone (NMP)-enabled solvent-mediated self-assembly process utilizing π-π stacking interactions to create 3D porous PANI@RGO composite gels.
• Characterized the composite's morphology, specific surface area, and pore structure, comparing it with water-assisted methods.
• Fabricated and tested AZIBs using the M-PANI@RGO-85% composite as a cathode material.

Main Results:

• Achieved molecular-level uniformity in PANI@RGO composites even at high PANI content (85%), named M-PANI@RGO-85%.
• The M-PANI@RGO-85% composite exhibited a significantly higher specific surface area (189.55 m² g⁻¹) and larger mesopores (36 nm) compared to water-assisted samples.
• The fabricated AZIBs demonstrated a high specific capacity (200 mAh g⁻¹ at 0.5 A g⁻¹), excellent rate performance (135 mAh g⁻¹ at 10 A g⁻¹), and remarkable low-temperature capability (148 mAh g⁻¹ at 1 A g⁻¹ at -20 °C).
• Quasi-solid-state batteries achieved high energy (198 Wh kg⁻¹) and power densities (11.3 kW kg⁻¹).

Conclusions:

• The π-π stacking-assisted and solvent-mediated self-assembly method is effective in designing advanced organic electrodes for AZIBs.
• This strategy overcomes the limitations of morphological aggregation and low surface area in PANI-based cathodes.
• The developed M-PANI@RGO-85% composite shows significant potential for high-performance and stable aqueous zinc-ion batteries.