Key Takeaways & Executive Findings
- •• • C-BCLP achieves a specific capacitance of 338.3 F g−1 at 1 A g−1 and retains 191.6 F g−1 at 10 A g−1, demonstrating high rate capability essential for power delivery applications. • • The electrode retains 99.1% of its initial capacitance after 10,000 charge-discharge cycles at 10 A g−1, indicating exceptional long-term stability for commercial supercapacitor deployment. • • The synthesis leverages sustainable biomass precursors (bacterial cellulose, lignosulfonic acid) and a simple carbonization process, offering a cost-effective and environmentally benign route compared to conventional carbon materials. • • The hierarchical porous structure combined with N/S co-doping and Fe3O4 nanoparticles enhances charge storage through synergistic effects, providing a blueprint for designing high-performance electrodes.
Abstract
The design of heteroatom-doped porous carbon materials integrated with metal oxide nanostructures has emerged as an efficient approach for improving the electrochemical performance of supercapacitors. A green and cost-effective method is reported for the fabrication of a hierarchical porous carbon composite from bacterial cellulose (BC), lignosulfonic acid (LS), and polypyrrole (PPy). LS serves as both an anchoring agent and a soft molecular template, directing the oxidative polymerization and uniform deposition of PPy onto the BC nanofibers in the presence of FeCl3 as the oxidizing agent. Subsequent carbonization under a nitrogen atmosphere results in the formation of an N/S co-doped carbon framework decorated with Fe3O4 nanoparticles, denoted C-BCLP. For comparison, a control composite consisting of BC and PPy without LS was carbonized to produce C-BCP. X-ray diffraction patterns confirm the synthesis of Fe3O4 nanoparticles and the preservation of the fibrous carbon structure. Electron microscopy shows that C-BCLP has a highly porous and conductive network with a homogeneous distribution of C, O, N, S, and Fe elements. Because of the combined effects of hierarchical porosity, heteroatom doping, and Fe3O4 incorporation, the C-BCLP electrode has high specific capacitances of 338.3 F g–1 at 1 A g–1 and 191.6 F g–1 at 10 A g–1. In addition, it has excellent cycling stability, retaining 99.1% of its initial capacitance after 10,000 charge-discharge cycles, outperforming the C-BCP electrode. The work suggests a promising way to develop next-generation high-performance supercapacitors.
1. Introduction
Conventional supercapacitor electrodes rely on activated carbons, graphene, or carbon nanotubes, which often involve complex synthesis routes and nonrenewable precursors, raising environmental and economic concerns. Their performance is frequently limited by poor rate capability and cycling stability, hindering widespread adoption in high-power applications. The challenge is to develop electrode materials that combine high specific capacitance, excellent rate performance, and long-term durability while adhering to green chemistry principles.
This work addresses these bottlenecks by engineering a hierarchical porous carbon composite derived from bacterial cellulose, lignosulfonic acid, and polypyrrole. The incorporation of Fe3O4 nanoparticles and N/S co-doping synergistically enhances charge storage, while the sustainable precursor and simple carbonization process offer a scalable, cost-effective route. The resulting C-BCLP electrode demonstrates superior electrochemical metrics, positioning it as a viable candidate for next-generation supercapacitors.
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Kummara Madhusudana Rao, Sung Soo Han (2026). Hierarchically porous fibrous carbon containing Fe3O4 particles and doped with both N and S derived from polypyrrole modified lignosulphonate-bacterial cellulose for use in high performance supercapacitors. New Carbon Materials. https://doi.org/10.1016/S1872-5805(26)61112-2
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Frequently Asked Questions
What is the specific capacitance retention at high current densities, and how does it compare to the control material?
C-BCLP retains 191.6 F g−1 at 10 A g−1, which is 56.6% of its capacitance at 1 A g−1 (338.3 F g−1). This rate capability is superior to the control C-BCP, which lacks the hierarchical porosity and heteroatom doping, indicating enhanced ion transport and charge storage kinetics.
How does the cycling stability of C-BCLP hold up under prolonged operation, and what mechanisms contribute to its durability?
C-BCLP retains 99.1% of its initial capacitance after 10,000 cycles at 10 A g−1. This exceptional stability is attributed to the robust fibrous carbon network that buffers volume changes of Fe3O4 nanoparticles during cycling, and the strong adhesion between the nanoparticles and the N/S-doped carbon matrix prevents detachment and agglomeration.
What is the role of lignosulfonic acid in the synthesis, and how does it affect the final material properties?
Lignosulfonic acid acts as both an anchoring agent and a soft template, directing the uniform polymerization of polypyrrole onto bacterial cellulose nanofibers. This leads to a more homogeneous distribution of Fe3O4 nanoparticles and a well-developed hierarchical porous structure after carbonization, which enhances the electrochemical performance compared to the control without LS.
What are the potential scalability and cost implications of this synthesis method for industrial production?
The synthesis uses low-cost, renewable biomass precursors (bacterial cellulose, lignosulfonic acid) and a simple carbonization process, which is amenable to scale-up. The use of FeCl3 as an oxidant is cost-effective. However, the production of bacterial cellulose on a large scale may require fermentation infrastructure, but the overall process is more sustainable and potentially cheaper than conventional carbon nanotube or graphene production.
How does the presence of Fe3O4 nanoparticles contribute to the overall capacitance, and are there any drawbacks?
Fe3O4 nanoparticles contribute pseudocapacitance through reversible redox reactions (Fe2+/Fe3+), enhancing the specific capacitance. However, they can suffer from poor electrical conductivity and volume changes during cycling. In this composite, the conductive carbon network and hierarchical porosity mitigate these issues, leading to improved rate performance and cycling stability.
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