Short answer: A CR2032 half-cell is built inside an argon glovebox by stacking, from the bottom: the positive case, your electrode, a few drops of electrolyte, the separator, more electrolyte, a lithium chip, a spacer, a spring and the negative cap, then sealing it in a coin cell crimper.
What you need
- CR2032 coin cell cases (316 stainless steel for high-voltage cathodes)
- Spacers and wave springs
- Lithium chips or punched lithium foil
- A separator punched to about 16-19 mm
- Electrolyte, for example 1 M LiPF6 in EC/DMC
- Your electrode disc (typically 12-15 mm), dried under vacuum
- A coin cell crimper, tweezers (plastic-tipped) and a pipette
Step-by-step assembly
- Dry everything. Dry electrodes and separators under vacuum and bring them into the glovebox (H2O and O2 below about 1 ppm is ideal).
- Place the positive case (the larger can) on the bench, open side up.
- Add the electrode, coated side up, centred in the case.
- Wet the electrode with a small drop of electrolyte (about 20 µL).
- Place the separator on top, making sure it fully covers the electrode.
- Add more electrolyte so the separator is fully wetted; 40-80 µL in total is typical for a CR2032.
- Add the lithium chip, centred, then the spacer and the spring.
- Place the negative cap (with its gasket) on top.
- Crimp the cell in the crimper at the recommended pressure, then wipe off any excess electrolyte.
- Rest the cell for several hours before testing so the electrolyte fully wets the electrode.
Common mistakes
- Separator smaller than the lithium chip, causing short circuits.
- Too much electrolyte, which leaks during crimping, or too little, which gives high resistance.
- Using 304 steel cases for cathodes above about 4.3 V, which can corrode.
- Skipping the spacer or spring, giving poor stack pressure and noisy data.
Frequently asked questions
Which way does the lithium chip go?
In a half-cell the lithium chip is the counter electrode and sits on top of the separator, under the spacer and spring.
How much electrolyte should I use in a CR2032?
Most labs use 40-80 µL; keep the amount constant across cells so results are comparable.
Where can I buy coin cell parts?
NanoLithium supplies coin cell cases, spacers, springs, lithium chips, separators and electrolytes in our Battery R&D Supply range, shipped worldwide.
