The shift toward alternative battery chemistries has brought sodium-ion technology into focus as a viable complement to lithium-ion systems, particularly for stationary storage and low-cost applications. Unlike lithium-ion batteries, which rely on well-established but geopolitically concentrated supply chains, sodium-ion batteries leverage abundant and widely distributed raw materials. However, their supply chains—particularly for critical components like hard carbon anodes and Prussian blue cathodes—are still in early development. Scaling these supply chains presents unique challenges, from material sourcing to manufacturing standardization.

Hard carbon stands as the leading anode material for sodium-ion batteries due to its ability to reversibly intercalate sodium ions at reasonable capacities. Unlike graphite in lithium-ion batteries, hard carbon does not require strict crystalline alignment, enabling a broader range of precursor materials. Biomass waste, such as coconut shells, lignin, and agricultural byproducts, is a common feedstock, offering a sustainable and low-cost route. Pilot-scale production has demonstrated capacities between 250–300 mAh/g, but consistency remains an issue. Variations in precursor composition and pyrolysis conditions lead to batch-to-batch performance differences, complicating large-scale adoption. Furthermore, the lack of standardized production methods means that each manufacturer employs proprietary processes, hindering interoperability and quality control across the supply chain.

Prussian blue analogs (PBAs) are emerging as promising cathode materials due to their open framework structure, which facilitates rapid sodium-ion diffusion. Their synthesis typically involves simple coprecipitation methods using iron cyanides and transition metal salts, avoiding the need for high-temperature calcination. Pilot facilities have achieved specific capacities of 120–160 mAh/g with decent cyclability, but challenges persist in eliminating lattice water and reducing defects during synthesis. Residual water can decompose during cycling, leading to gas evolution and capacity fade. While some producers have developed low-defect PBA variants, scaling these optimized processes requires tight control over reaction kinetics and purification steps—factors that are difficult to maintain consistently in high-volume production.

The raw material supply for these components is geographically dispersed but faces logistical and processing bottlenecks. Sodium carbonate and iron cyanide, key precursors for PBAs, are commodity chemicals with established production networks. However, the specialized grades required for battery applications are not yet widely available at scale. Similarly, hard carbon feedstocks, though abundant, lack dedicated collection and preprocessing infrastructure. Pilot lines often rely on fragmented supplier networks, leading to variability in purity and particle morphology. Establishing dedicated supply agreements and quality standards will be critical to transitioning from lab-scale to gigawatt-hour production.

Manufacturing scalability is another hurdle. Electrode coating and cell assembly for sodium-ion batteries can largely borrow from lithium-ion processes, but material-specific adjustments are necessary. Hard carbon’s lower density compared to graphite requires thicker electrode coatings to achieve comparable energy densities, posing challenges in slurry formulation and drying. PBAs, being moisture-sensitive, demand dry room conditions during electrode processing—a requirement that adds cost and complexity. Pilot lines have successfully integrated these adaptations, but translating them to high-speed, continuous production will require further optimization of parameters such as binder selection, solvent recovery, and defect detection.

Economic viability hinges on reducing costs through economies of scale and process innovation. Hard carbon production is currently more expensive than graphite due to lower yields and energy-intensive pyrolysis. However, leveraging waste biomass and optimizing reactor designs could narrow this gap. For PBAs, reducing reliance on high-purity reagents and improving synthesis yields will be essential. Early estimates suggest that at scale, sodium-ion cells could achieve material costs 20–30% lower than lithium-ion LFP cells, but this depends on overcoming the current inefficiencies in precursor and electrode manufacturing.

Regulatory and environmental considerations also play a role in shaping these nascent supply chains. Unlike cobalt or lithium, sodium and iron are not subject to the same geopolitical constraints, but the handling of cyanide-based precursors for PBAs requires strict safety protocols. Additionally, the sustainability benefits of biomass-derived hard carbon could position it favorably in markets with strong environmental regulations, provided that lifecycle assessments validate its lower carbon footprint compared to synthetic carbons.

The roadmap for scaling these supply chains involves several key steps. First, vertical integration between material suppliers and cell manufacturers can ensure consistent quality and reduce lead times. Second, collaborative standardization efforts—akin to those seen in early lithium-ion development—will be necessary to harmonize testing methods and material specifications. Finally, public and private investment in pilot-to-production facilities will de-risk the transition to mass manufacturing. Several gigafactories dedicated to sodium-ion batteries are already in planning stages, signaling growing confidence in the technology’s potential.

While sodium-ion batteries may not replace lithium-ion in high-energy-density applications, their development represents a strategic diversification of the energy storage landscape. The supply chains for hard carbon anodes and Prussian blue cathodes, though immature, are advancing rapidly, driven by the demand for sustainable and geopolitically resilient alternatives. Overcoming the remaining scalability challenges will require concerted effort across material science, process engineering, and supply chain logistics—a task that is now underway as the industry moves from pilot-scale to commercial production.