Electrode Fabrication for Sodium-Ion Startups

Electrode fabrication for sodium-ion startups follows the same core steps as lithium-ion: mix, coat, dry, calendar, cut and dry again. What changes is where the risks sit: hard carbon behaviour, sodium cathodes that can be sensitive to moisture, and the need to record every batch so early cell results can be trusted. This guide walks through each step with the sodium-specific points to watch, and helps you decide whether to make early electrodes yourself or outsource them.

Electrodes decide more of your results than many founders expect. When the Faraday Institution’s NEXGENNA team scaled a sodium-ion chemistry from coin cells of about 1 cm² to three-layer pouch cells of about 300 cm², the next steps they named were all electrode-level: more active material in the coating, optimised electrode thickness, better anode-cathode balance and less electrolyte, as described in the Faraday Institution case study.

The electrode fabrication process map

Step	What happens	Sodium-ion watch-point
1. Mixing	Active material, conductive carbon and binder dispersed in solvent	Hard carbon and some cathodes disperse differently from graphite or NMC; record mixing order and time
2. Coating	Slurry cast on foil at target loading	Set loading from full-cell balance, not from half-cell capacity alone
3. Drying	Solvent removed in the coater oven	Record conditions; moisture picked up now carries into cells
4. Calendering	Electrode pressed to target density	Hard carbon density targets differ from graphite; test before fixing
5. Slitting / punching	Cut to cell size	Keep edges clean; burrs cause shorts
6. Final drying	Vacuum drying before assembly	Use the protocol for your binder and move straight to a dry room or glovebox

 

Electrode fabrication for sodium-ion startups: the hard carbon anode

Hard carbon is the main anode material studied for sodium-ion, and its first-cycle loss often sets how much cathode a full cell needs. Precursor and processing change capacity and first-cycle efficiency, so treat each new grade as a new material. Our article on hard carbon anodes for sodium-ion cells covers capacity, first-cycle efficiency and precursors.

• Use one hard carbon grade and batch for a whole study.
• Measure loading on every sheet, not just one.
• Find the calendered density that balances energy and electrolyte wetting before you scale.
• Record first-cycle efficiency from coin cells for each electrode batch.

Cathode electrodes

Sodium cathodes fall into families such as layered oxides, polyanion compounds and Prussian blue analogues, each with its own handling needs. Ask your material supplier about air and moisture sensitivity, recommended binder and drying. Keep sensitive powders sealed and process them in the driest conditions you have.

Current collector choice

Foil choice affects cost, weight and process settings. Confirm with your material supplier and your cell design which current collector each electrode needs, and test adhesion and resistance on the foil you plan to scale with, rather than switching foils between the coin-cell and pouch-cell stages.

Moisture control from day one

Water in electrodes harms cell performance, and startups often lose months chasing problems that started with a humid coating room. Set up a drying record for every batch: oven settings, time, vacuum level and how long electrodes sat before assembly. Our guide on vacuum drying protocols gives starting points by binder.

Build or outsource your first electrodes?

Stage	In-house makes sense when…	Outsourcing makes sense when…
Material screening	You already have a coater and dry space	You need a few good sheets fast
First pouch cells	Your process is stable and repeatable	You need loading control and quality data you cannot yet produce
Pilot batches	You plan to run your own line soon	Capital is better spent on materials R&D

 

Many startups outsource early electrodes, then bring coating in-house once the recipe is fixed. Our custom electrode sheets and rolls service makes electrodes from customer materials. Good electrodes cannot rescue a weak chemistry, and small batches show trends, not production performance.

A simple batch record

Keep one line per electrode batch: material lot, recipe, mixing details, coater settings, loading measurements, calendered thickness and density, drying record and where the electrodes went. When a cell result surprises you, this record tells you whether to look at the material or the process. This guide was prepared by the electrode team at Canrd Technology.

Frequently asked questions

Can I use a lithium-ion coating line for sodium-ion electrodes?

In most cases the equipment is the same: mixers, coaters, calenders and vacuum ovens. Settings change, though, for mixing, loading, calendered density and drying. Run small trials with your sodium materials before relying on lithium-ion recipes, and record every change.

What current collector do sodium-ion electrodes use?

It depends on the electrode and your cell design. Confirm the foil with your material supplier, test adhesion and resistance on it, and keep the same foil from coin cells through pouch cells so results stay comparable.

How much hard carbon do I need for a first electrode batch?

Work it out from electrode area, target loading, coated sides, number of cells and repeats, then add a margin for mixer and coating losses. Share the estimate with your coating partner, who can confirm it for their equipment.

 

Need sodium-ion electrodes made to spec? Send us your materials and targets, and we will scope a first batch with you: reach our engineers.