Polyaniline-Based Supercapacitor Electrode Materials

Polyaniline (PANI) has emerged as a leading conductive polymer for supercapacitor electrodes thanks to its intrinsic redox activity, high electrical conductivity and facile synthesis. Energy storage in PANI relies predominantly on pseudocapacitive Faradaic reactions at nitrogen sites, affording high specific capacitance values compared with purely electric double-layer materials. Morphological control—ranging from nanofibres and nanotubes to three-dimensional interconnected networks—has been essential to maximise ion accessibility and minimise diffusion pathways. Nonetheless, pure PANI electrodes often suffer from volumetric swelling, structural degradation over long cycling and a compromise between conductivity and optimal pore structure. To overcome these drawbacks, researchers have developed composite architectures combining PANI with carbon substrates, metal oxides or porous matrices, and have explored novel doping strategies to balance mechanical stability with charge mobility. Advances in binder-free film deposition and in situ polymerisation within mesoporous hosts have further improved electrode integrity and rate performance. Ongoing efforts focus on integrating PANI-based electrodes into lightweight, flexible and high-energy devices suitable for portable electronics, grid stabilisation and electric-vehicle applications.

Research from Nature Portfolio

One foundational study achieved a three-dimensional PANI architecture through simultaneous strong-inorganic and weak-organic acid doping, creating a molecular composite with an interconnected network that supports metallic-like conductivity. This binary-doped material sustained a near constant specific capacitance of 350 F g⁻¹ across a broad current range and exhibited stable cycling over hundreds of high-rate cycles. Another seminal report demonstrated the use of amino-functionalised Fe₃O₄ microspheres to direct the nucleation and growth of PANI into hierarchical nanostructures. By tuning nucleation sites and applying external magnetic fields, this approach generated tailored PANI morphologies—flowers, tentacles and towers—each with distinct surface wettability, offering a route to optimise electrode–electrolyte interactions and interfacial charge transfer.

Research from all publishers

Recent work has embedded PANI within the pores of high-surface-area mesoporous silicon obtained via magnesiothermic reduction. In situ polymerisation produced an mSi-PANI composite that outperformed both pure PANI and silica-based analogues, owing to a retained network of 10 nm mesopores enveloped by an electrochemically accessible polymer matrix.

Another study reported binder-free sodium phytate-doped PANI films deposited directly onto fluorine-doped tin oxide. Symmetric devices constructed from these films delivered high specific capacities of 550 F g⁻¹ at 1 A g⁻¹ and maintained 355 F g⁻¹ at 40 A g⁻¹, with low solution and charge-transfer resistances and 90 % capacity retention over 1 000 cycles.

A third investigation explored polyelectrolyte complex membranes loaded via a two-step PANI deposition. Crossflow polymerisation across polyelectrolyte membranes doubled electrode capacitance and produced flexible, high-performance pseudocapacitor electrodes capable of sustaining rapid charge–discharge cycling.

Polyaniline-Based Supercapacitor Electrode Materials publication trend

The graph below shows the total number of articles in polyaniline-based supercapacitor electrode materials across all publications each year (not limited to Nature Index journals).

Technical terms

Polyaniline (PANI): A conductive polymer exhibiting reversible redox transitions used for pseudocapacitive energy storage.

Supercapacitor: An electrochemical device that stores energy via electric double-layer and/or pseudocapacitive mechanisms for high power delivery.

Pseudocapacitance: Charge storage arising from fast, reversible Faradaic reactions at the electrode surface.

Specific capacitance: A measure of stored charge per unit mass of electrode material (F g⁻¹).

Mesoporous: A material possessing pore diameters between 2 and 50 nm, facilitating ion transport.

Dopant: A chemical species introduced to a polymer to modulate its electrical conductivity and structural properties.

References

1. 3D Polyaniline Architecture by Concurrent Inorganic and Organic Acid Doping for Superior and Robust High Rate Supercapacitor Performance. Scientific Reports (2016).
2. Amino-Fe3O4 Microspheres Directed Synthesis of a Series of Polyaniline Hierarchical Nanostructures with Different Wettability. Scientific Reports (2016).
3. Polyaniline inside the pores of high surface area mesoporous silicon as composite electrode material for supercapacitors. RSC Advances (2022).
4. Exploring the Functional Properties of Sodium Phytate Doped Polyaniline Nanofibers Modified FTO Electrodes for High-Performance Binder Free Symmetric Supercapacitors. Polymers (2021).
5. Two-step polyaniline loading in polyelectrolyte complex membranes for improved pseudo-capacitor electrodes. e-Polymers (2021).