Biochar-Based Materials for Electrochemical Energy Storage

Biochar produced from the thermochemical conversion of biomass has emerged as a versatile and sustainable platform for electrode materials in electrochemical energy storage devices. Its intrinsic characteristics – high carbon content, porous architecture and amenability to surface functionalisation – make biochar an attractive alternative to conventional carbonaceous materials. Through controlled pyrolysis conditions and post-treatment activation, biochar can attain a hierarchical pore network that enhances ion diffusion and charge storage. Incorporation of heteroatoms such as nitrogen, sulphur or phosphorus, whether via in situ self-doping or post-synthetic modification, introduces active sites and pseudocapacitive mechanisms, further boosting performance. Hybridisation with metal oxides or conductive polymers can impart synergistic effects, combining electric double-layer capacitance with faradaic redox reactions. These design strategies have delivered biochar-based electrodes with specific capacitances comparable to or surpassing commercial activated carbons, while offering a low-cost, environmentally benign route to large-scale production. Practical applications span supercapacitors, hybrid battery systems and electrocatalysis for water splitting, underscoring the global relevance of biomass valorisation in the transition to sustainable energy technologies.

Research from Nature Portfolio

Recent studies have demonstrated innovative pathways for converting waste-derived biochars into high-performance supercapacitor electrodes. One seminal example converted nickel-laden biochars, sourced from dairy manure and sewage-sludge biomass, into robust supercapacitor materials via microwave treatment. The process transformed surface-bound nickel into active NiO and NiOOH phases, doubling the specific capacitance and delivering stable charge–discharge behaviour over extended cycling. Another investigation harnessed hydrothermal carbonisation to integrate copper oxide nanoparticles with algae-derived biochar. The resulting composite exhibited a hierarchical pore network and uniform CuO dispersion, achieving a capacitance of over 350 F g⁻¹ and demonstrating excellent rate capability and cycle stability for eco-friendly energy storage.

Biochar-Based Materials for Electrochemical Energy Storage publication trend

The graph below shows the total number of articles in biochar-based materials for electrochemical energy storage across all publications each year (not limited to Nature Index journals).

Technical terms

Biochar: A carbon-rich solid produced by thermochemical conversion of biomass under limited oxygen, used as an electrode precursor due to its high surface area and tunable porosity.

Pyrolysis: The thermal decomposition of organic material at elevated temperatures in the absence of oxygen, fundamental to biochar formation.

Activation: A post-pyrolysis process (chemical or physical) that develops porosity and increases surface area, critical for enhancing charge storage capacity.

Specific Capacitance: The capacitance per unit mass of an electrode material, typically expressed in farads per gram (F g⁻¹), indicating its ability to store charge.

Heteroatom Doping: The incorporation of non-carbon atoms (e.g. N, S, P) into the carbon matrix to introduce active sites, improve conductivity and enable pseudocapacitive behaviour.

Overpotential: The extra potential beyond the thermodynamic requirement needed to drive an electrochemical reaction, relevant in assessing electrode kinetics and efficiency.

References

1. Converting Ni-loaded biochars into supercapacitors: Implication on the reuse of exhausted carbonaceous sorbents. Scientific Reports (2017).
2. CuO nanoparticles mixed with activated BC extracted from algae as promising material for supercapacitor electrodes. Scientific Reports (2023).
3. A Review on Production and Surface Modifications of Biochar Materials via Biomass Pyrolysis Process for Supercapacitor Applications. Catalysts (2022).
4. Valorization of Biomass-Derived Polymers to Functional Biochar Materials for Supercapacitor Applications via Pyrolysis: Advances and Perspectives. Polymers (2023).
5. A state-of-the-art review of N self-doped biochar development in supercapacitor applications. Frontiers in Energy Research (2023).
6. The role of feedstock and activation process on supercapacitor performance of lignocellulosic biochar. Biomass and Bioenergy (2024).