Carbon-Based Anode Materials for Potassium-Ion Batteries

Potassium-ion batteries (PIBs) have emerged as a promising alternative to lithium-ion systems due to the natural abundance and low cost of potassium. Carbon-based anodes, encompassing soft carbons, hard carbons and graphitic derivatives, offer a versatile platform for accommodating the large K+ ion, but require careful optimisation of structure and chemistry to overcome sluggish kinetics and volume changes. Key strategies include the introduction of hierarchical porosity to facilitate ion transport, expansion of interlayer spacing to ease intercalation, and heteroatom doping to create active sites and enhance electronic conductivity. Moreover, engineering of the solid-electrolyte interphase on carbon surfaces has been shown to stabilise cycling and improve Coulombic efficiency. Recent advances demonstrate that combining multiple design elements—such as pore regulation, defect engineering and dual-dopant chemistries—can yield high reversible capacities, excellent rate performance and extended cycle life. Ongoing research is directed towards scalable synthesis routes, mechanistic insights via in situ characterisation and integration of carbon anodes in full PIB cells, with the goal of achieving safe, sustainable and cost-effective energy storage solutions for grid and portable applications.

Research from Nature Portfolio

Highly nitrogen-doped carbon nanofibres have been demonstrated as soft-carbon anodes with exceptional rate capability and cyclability. The enlarged interlayer spacing and abundant surface defects enable rapid surface-dominated K+ storage, delivering capacities of around 248 mAh g–1 at low rates and retaining over 100 mAh g–1 even at very high current densities. Quantitative kinetics analysis and theoretical modelling confirm the predominance of capacitive processes, while full cells pairing the nanofibre anode with a Prussian blue cathode achieve practical reversible capacities near 195 mAh g–1. This work underscores the role of tailored nitrogen doping in reconciling high energy and power in PIB anodes.

Carbon-Based Anode Materials for Potassium-Ion Batteries publication trend

The graph below shows the total number of articles in carbon-based anode materials for potassium-ion batteries across all publications each year (not limited to Nature Index journals).

Technical terms

Interlayer spacing: The distance between adjacent graphene layers in carbon, which influences ease of K+ intercalation.

Heteroatom doping: The intentional incorporation of non-carbon elements (e.g., N, S, O) into the carbon matrix to modify electronic structure and create active sites.

Hard carbon: A non-graphitisable carbon with disordered domains and micropores, often derived from biomass or synthetic precursors.

Potassiation kinetics: The rate processes governing the insertion and extraction of K+ ions into the electrode material.

Solid-electrolyte interphase (SEI): A passivation layer formed at the electrode–electrolyte interface that affects ionic transport and cycle stability.

Capacitive storage: Charge storage dominated by surface adsorption rather than bulk intercalation, enabling rapid charge–discharge behaviour.

References

1. A review of hard carbon anode: Rational design and advanced characterization in potassium ion batteries. InfoMat (2022).
2. Highly nitrogen doped carbon nanofibers with superior rate capability and cyclability for potassium ion batteries. Nature Communications (2018).
3. Defect Engineering of Disordered Carbon Anodes with Ultra-High Heteroatom Doping Through a Supermolecule-Mediated Strategy for Potassium-Ion Hybrid Capacitors. Nano-Micro Letters (2023).
4. Pore structure and oxygen content design of amorphous carbon toward a durable anode for potassium/sodium‐ion batteries. Carbon Energy (2024).
5. Nitrogen and Sulfur Co‐Doped Hierarchically Porous Carbon Nanotubes for Fast Potassium Ion Storage. Small (2022).