Samples: what to send and how

A separate quotation is needed below the minimum. We do run single-cell jobs occasionally, but the report then says that the result is from one cell, in the summary and not in a footnote.

Two identifiers travel with every sample. Yours, which we never alter, and ours, which is assigned at intake in the form NG-26-118 — year of arrival, then a counter that restarts in January. Both appear on every table of every report, so a result can be traced back to a physical object two years later.

The packing list must state

1. Your identifier for each item, written on the item itself and not only on the box.
2. Sample type, mass or count, and the format.
3. Measured open-circuit voltage for every cell, with the date it was measured.
4. Chemistry as far as you are willing to disclose it, and any known hazard.
5. Method codes requested, or the attached protocol if the work is bespoke.
6. A named technical contact who can answer a question within two working days.
7. Return instruction: back to you, disposal by us, or retain for later work.

A signed scan sent to samples@nickelgrid.cloud on the day of dispatch is what we check against the physical delivery. Intake takes about two hours for a dozen items and ends with a confirmation listing our identifiers against yours.

Electrode coating from supplied powder

When only powder exists, we make the electrodes. Five working days, and the recipe is yours to set or ours to choose — but it is recorded either way, because a cycling result on an unknown electrode is worth very little.

Default composition

92 : 4 : 4 active material, conductive carbon, binder by mass

Mixing

planetary, 20 minutes at 800 rpm with a 10-minute vacuum de-aeration step

Coating

doctor blade on 16 µm aluminium or 9 µm copper, wet gap 60–220 µm

Loading

typically 8–14 mg cm⁻², held to ±4 % across the usable area

Drying

80 °C in air, then 12 h at 110 °C under vacuum before transfer into the glove box

Calendering

optional, to a stated porosity; we report the achieved density rather than the target

Punching

14 mm discs, mass of each disc recorded to 0.1 mg

Every batch keeps two witness discs that are weighed and archived but never cycled. If a cycling result later looks implausible, those discs are the first thing we go back to.

A rejected shipment is held, photographed and reported the same day; nothing is thrown away and nothing is tested. These are the grounds, and they are not negotiable at the dock:

• No packing list, or a list that does not match the physical contents.
• Cells above 30 % state of charge, or cells whose stated voltage disagrees with our measurement by more than 100 mV.
• Powder in a single bag with a visibly compromised seal, where moisture exposure cannot be excluded.
• Unlabelled items that cannot be distinguished from one another.
• A declared hazard without the corresponding safety data sheet.
• Any item outside the maxima in the table above, unless agreed in the quotation.

In 2025 we rejected eleven of 214 incoming shipments. Nine were missing or contradictory paperwork; two were cells at full charge.

Unused material is held for 90 days after the report is issued, in the condition it arrived in, under argon where that is how it came. After 90 days we write once and then act on whatever the packing list said.

• Return. At your cost and under your transport arrangement. Cells are returned at the state of charge they were last at, which is normally near zero.
• Disposal. Through a licensed route, with a disposal note in the report file.
• Retention beyond 90 days. Possible, billed as storage by the shelf-month, and sensible when a follow-up job is likely.
• Disassembled material from a teardown is never returned. Rinsed electrodes and sampled electrolyte are not transportable in any state we would be willing to certify.

Raw measurement data outlives the sample: five years for the time series, ten for the report, as described under data retention.