The global transition toward renewable energy systems such as wind and solar power has intensified the need for advanced energy storage technologies capable of balancing intermittency while maintaining long operational lifetimes. Among various candidates, supercapacitors have attracted sustained attention due to their high power density, rapid charge–discharge capability, and exceptional cycling stability. However, their broader deployment remains constrained by the performance limitations and environmental costs associated with conventional electrode materials.
In this context, biomass-derived carbon aerogels have emerged as a promising alternative, offering renewable sourcing, tunable microstructures, and compatibility with green manufacturing pathways. Lignin, one of the most abundant aromatic biopolymers on Earth and a major byproduct of the pulp and paper industry, represents an especially attractive carbon precursor. Yet transforming lignin into high-performance supercapacitor electrodes requires precise control over both pore architecture and surface chemistry.
The newly reported work addresses this challenge by developing a synergistic structure–doping regulation strategy for lignin-based carbon aerogels. Magnesium lignosulfonate, which inherently contains sulfur, was employed as the primary carbon source, while sodium alginate served as a natural gel-forming agent. Phytic acid played a dual role: acting simultaneously as a phosphorus dopant and as an acidity regulator that directs gelation behavior and structural evolution.
During freeze-drying and subsequent carbonization, phytic acid promoted the formation of uniform spherical hierarchical structures within the aerogel matrix. These spheres, enriched with phosphorus and oxygen species, effectively confined heteroatoms while increasing interlayer spacing and accessible surface area. High-temperature treatment further interconnected the pore network, yielding a mesopore-dominated architecture favorable for fast electrolyte ion transport.
Electrochemical evaluation revealed that the optimized carbon aerogel, prepared at a specific precursor ratio and carbonized at 700 °C, achieved a high specific capacitance of 362 F g⁻¹ at 0.5 A g⁻¹. When assembled into a symmetric supercapacitor device, it delivered an energy density of 40.1 W h kg⁻¹ at a power density of 700 W kg⁻¹, while retaining 82.5% of its capacitance after 20,000 charge–discharge cycles. These metrics compare favorably with many previously reported lignin-derived carbon materials.
Mechanistic analysis attributes this performance to the cooperative effects of structural hierarchy and dual heteroatom functionality. The spherical mesoporous framework facilitates efficient electric double-layer formation and rapid ion diffusion, while phosphorus- and sulfur-containing functional groups introduce additional pseudocapacitive contributions through reversible surface redox reactions. Together, these features overcome the traditional trade-offs between power capability, energy density, and cycling stability that often limit carbon-based supercapacitors.
Beyond performance metrics, the study highlights a sustainable materials design philosophy. By exploiting the intrinsic sulfur content of magnesium lignosulfonate for in situ self-doping and using phytic acid as a multifunctional additive, the approach minimizes chemical inputs and simplifies processing. This strategy not only advances the practical utilization of industrial lignin waste but also provides a generalizable framework for designing high-performance biomass-derived energy storage materials.
Journal of Bioresources and Bioproducts
Experimental study
Not applicable
Synergistic Enhancement of Electrochemical Performance in Lignin-Based Carbon Aerogel Supercapacitors through Phytic Acid-Induced Spherical Structure Formation and Dual P/S Heteroatom Doping
27-Jan-2026