Π–Π Stacking‐Assisted Self‐Assembly Fabricates Highly Uniform PANI@RGO Cathodes Toward High‐Performance Aqueous Zinc‐Ion Batteries

Why It Matters

The breakthrough tackles polymer cathode aggregation and low surface area, unlocking higher capacity and rate capability for aqueous zinc‑ion batteries that could power large‑scale, low‑cost energy storage systems.

Key Takeaways

• π–π stacking yields uniform PANI@RGO composite
• 85% PANI content achieved without aggregation
• Specific surface area reaches 189.55 m² g⁻¹
• Capacity 200 mAh g⁻¹ at 0.5 A g⁻¹
• Retains 148 mAh g⁻¹ at –20 °C

Pulse Analysis

Aqueous zinc‑ion batteries (AZIBs) have attracted attention for their safety, low cost, and environmental friendliness, yet their commercial traction is hampered by cathode limitations. Organic polymers such as polyaniline (PANI) offer rapid redox kinetics and sustainability, but they tend to aggregate during synthesis, reducing active surface area and compromising ion transport. The new N‑methyl‑2‑pyrrolidone (NMP)‑mediated self‑assembly approach exploits π–π interactions between PANI chains and reduced graphene oxide (RGO), producing a three‑dimensional porous network that preserves molecular‑level uniformity even at 85 % PANI loading.

The solvent‑mediated strategy fundamentally reshapes the electrode architecture. By replacing water with NMP, the researchers suppress uncontrolled nucleation, allowing PANI to intercalate onto RGO sheets via strong π–π stacking. This yields a specific surface area of 189.55 m² g⁻¹ and mesopores averaging 36 nm—more than double the surface area and triple the pore size of conventional water‑based composites. The enlarged mesoporous framework facilitates swift zinc‑ion diffusion and mitigates volume changes during cycling, directly translating into superior electrochemical performance.

Performance data underscore the practical impact. The M‑PANI@RGO‑85 % cathode delivers 200 mAh g⁻¹ at 0.5 A g⁻¹ and sustains 135 mAh g⁻¹ at an aggressive 10 A g⁻¹, while retaining 148 mAh g⁻¹ at –20 °C, a temperature range where many AZIBs falter. In a quasi‑solid‑state configuration, the cell reaches 198 Wh kg⁻¹ energy density and 11.3 kW kg⁻¹ power density, positioning it competitively against emerging multivalent systems. The method’s scalability and compatibility with existing roll‑to‑roll processes suggest a clear pathway toward commercial, high‑performance, low‑temperature AZIBs.