Sodium-ion
Also known as: Na-ion · SIB
No lithium and no cobalt; it charges below zero and declares more cycles than any other, but in finished products weighs like lead. As of 2026 no product in the catalogue uses it.
What changes for you
It is the chemistry of the cold. UNIGRID declares for its Na+Casa charging from −20 °C and discharging from −40 °C, with entirely passive cooling; the Bluetti Pioneer Na power station charges from −15 °C and at −25 °C still delivers 80% of capacity. No graphite-anode lithium cell does anything like it.
The price is paid in weight, and more than the cell alone suggests. The Bluetti Pioneer Na does 900 Wh on 16 kg, that is 56 Wh/kg: like an AGM lead-acid battery and less than an LTO. The UNIGRID Na+Casa reaches 85 Wh/kg (9,250 Wh on 108.9 kg). The CATL Naxtra cell alone declares 175 Wh/kg, more than EVE's LFP cell: between cell and finished product more than half is lost, because these are first-generation products. Always look at the weight of the system, not that of the cell.
The declared cycles are the highest of all and the least comparable: Bluetti over 4,000 with no threshold, Biwatt 8,000 at 25 °C, 0.5C and 80% depth of discharge, CATL over 15,000 at 80% on the cell for grid-scale installations. UNIGRID itself writes "over 10,000" on the product page and "up to 30,000 at 80%" on the home page. Without a threshold and conditions the number is worth nothing, and here it is worth even less.
The data
| Contains lithium | no |
|---|---|
| Contains cobalt | no |
| UN number for transport | UN 3551 / 3552 |
What the products in the catalogue declare
No product in the catalogue uses this chemistry, today.
In place of lithium ions, sodium ions move; the anode is hard carbon, and the cathodes differ from manufacturer to manufacturer: sodium chromium oxide in UNIGRID, sodium iron pyrophosphate-phosphate in Biwatt, sodium iron manganese oxide in Bluetti. CATL uses an aluminium foil in place of copper on the anode. None of the formulations seen contains cobalt or lithium, and the JRC writes that it "does not depend on any critical raw material". But "without cobalt" does not mean "without heavy metals": the UNIGRID cell contains chromium.
For transport it has had its own UN numbers since 2025, UN 3551 alone and UN 3552 inside or together with a device, with the same special provisions as lithium; marking the rated energy is mandatory on batteries produced after 31 December 2025. It can travel discharged and verifiably short-circuited: which is why Bluetti writes that the Pioneer Na ships at zero watts. EU regulation 2023/1542 does not impose recycled-content quotas on it, because it contains no cobalt, lithium, nickel or lead.
On safety we give no numbers: the primary tests on sodium were not accessible, and a manufacturer's statement is not a measurement. In Europe there are today three residential storage units with a public datasheet (UNIGRID Na+Casa, Biwatt PowerNest R5, the German Revolta since September 2026) and one power station (Bluetti Pioneer Na). The American Natron Energy closed on 3 September 2025 and does not go into the catalogue.
Related entries
Frequently asked questions
How many products in the catalogue use sodium-ion?
No product in the catalogue uses this chemistry, today.
Sources: 1 · 2 · 3 · 4 · 5 · 6 · 7 · 8 · 9 · 10 · 11 · 12 · 13