Sodium-ion buyer's guide
Sodium-ion cells are now available in real quantities and real sizes. Through our factory sourcing we can supply ten cylindrical sodium-ion cells, from small 18650s up to 15Ah 46145 cans, in three different chemistries. A few are already in stock in our store.
This guide is organized by chemistry first, because the cathode decides how a cell behaves far more than its size does. Pick the chemistry that fits your build, then pick the size.
-40°C
discharge, every cell
Up to 40C
continuous discharge
The full lineup at a glance. Every value is a manufacturer rating.
The basics
Why sodium-ion at all?
A sodium-ion cell works like a lithium-ion cell: ions shuttle between a cathode and an anode through an electrolyte. The ion is sodium, which comes from ordinary salt, and the anode is hard carbon instead of graphite. For off-grid builders that brings three real advantages:
❄️
Cold tolerance
LiFePO4 shouldn't be charged below 0°C. Many sodium-ion cells charge down to -20°C, and every cell here discharges down to -40°C.
⚡
High power
Several of these cells are rated for 20C continuous discharge, and one 18650 is rated for 40C.
📦
Safer storage and shipping
Sodium-ion is widely reported to tolerate very low states of charge better than lithium. Confirm the limit for your specific cell before relying on it.
The trade-off is energy density. Sodium-ion stores less energy per kilogram than lithium: the cells here range from about 73 to 133 Wh/kg. If weight is your top priority, LFP or NMC still wins.
Chemistry 1
Layered oxide
Layered oxide cathodes pack sodium between sheets of transition-metal oxide (nickel, iron and manganese). It's the energy-dense, all-rounder sodium chemistry, and it has the widest range of sizes.
Pros
-
✓Highest energy density of the three chemistries, about 89 to 133 Wh/kg in this lineup
-
✓Most sizes charge down to -10°C or -20°C
-
✓Strong power: 15C to 20C continuous discharge on most sizes
-
✓The widest choice of sizes, from 18650 to 33140
Cons
-
✕The widest voltage window (1.5V to 3.9V or more), which is harder to match to inverters and 12V gear
-
✕More sensitive to running at the edges of that window. Independent lab tests of early layered-oxide 18650s found faster wear than the spec sheets suggest when cycled to full voltage.
Available Sodium-ion Layered Oxide sizes
| Size |
Capacity |
Energy |
Weight |
Charge temp |
Cont. discharge |
Cycle life |
| 18650 |
1,100mAh |
3.3Wh |
37g |
-10 to 55°C |
15C |
2,000+ |
| 26650 HP |
2.5Ah |
7.5Wh |
75g |
-10 to 75°C |
20C |
2,000+ |
| 26650 UT |
2.5Ah |
7.5Wh |
74g |
-20 to 75°C |
20C |
2,000+ |
| 32700 |
4.5Ah |
13.5Wh |
125g |
-20 to 75°C |
20C |
2,000+ |
| 32140 |
10Ah |
30Wh |
265g |
-10 to 70°C |
10C |
3,000+ |
| 33140 (aluminium) |
10Ah |
30Wh |
225g |
-20 to 75°C |
20C |
2,000+ |
Good fit for
Cold-climate solar storage (33140)E-bikes, go-karts & robotics (26650 UT, 32700)General DIY packs (18650)
In stock at OGS
18650 Sodium-Ion Cell
Layered oxide, 1,100mAh
32140 Sodium-Ion Cell
Layered oxide, 10Ah (30Wh)
210Ah Prismatic Cell
Layered oxide, for big storage builds
Chemistry 2
NFPP (sodium iron phosphate-pyrophosphate)
NFPP is a phosphate cathode, and it's best thought of as the LFP of the sodium world. It gives up some energy density in exchange for stability, long cycle life and a narrower voltage window.
Pros
-
✓Long cycle life: up to 3,000+ cycles on the 46145
-
✓The narrowest top voltage of the three (3.4V to 3.7V), which makes BMS and inverter matching easier
-
✓Thermally stable phosphate structure
-
✓The 18650 is rated for an unusual 40C continuous discharge
Cons
-
✕The lowest energy density in this lineup, about 73 to 95 Wh/kg
-
✕The large NFPP cells (32140 and 46145) only charge from 0°C up. They still discharge to -40°C, but they aren't the pick if cold charging is the reason you want sodium.
-
✕The large cells are limited to a 1C charge
Available Sodium-ion NFPP sizes
| Size |
Capacity |
Energy |
Weight |
Charge temp |
Cont. discharge |
Cycle life |
| 18650 |
850mAh |
2.6Wh |
35g |
-10 to 60°C |
40C |
1,000+ |
| 32140 |
7Ah |
21Wh |
240g |
0 to 45°C |
15C |
2,000+ |
| 46145 (aluminium) |
15Ah |
43Wh |
450g |
0 to 60°C |
10C |
3,000+ |
Good fit for
Long-life storage in a heated space (46145)Very high-current small packs (18650)
In stock at OGS
18650 Sodium-Ion Cell
NFPP, 40C high-rate
160Ah Prismatic Cell
NFPP, 6,000+ cycles
Chemistry 3
Prussian blue
Prussian blue analogue cathodes use an open, cage-like iron-cyanide framework that sodium ions move through very easily. That makes them excellent at power, and they're cheap to produce.
Pros
-
✓Very fast charging: rated for 10C continuous charge
-
✓High continuous discharge, around 200A from a single cell
-
✓Charges down to -20°C and has the widest discharge range in this lineup (-40 to 80°C)
-
✓A slightly higher 3.12V nominal and a narrow 2.0V to 3.6V window
Cons
-
✕Only one size is available (46145)
-
✕The newest of the three chemistries commercially, so it has the least real-world track record
-
✕Moderate energy density, about 101 Wh/kg
Available Sodium-ion Prussian blue sizes
| Size |
Capacity |
Energy |
Weight |
Charge temp |
Cont. discharge |
Cycle life |
| 46145 (aluminium) |
13Ah |
40.6Wh |
400g |
-20 to 60°C |
200A (15.3C) |
2,000+ |
Good fit for
Engine startingRegenerative brakingSolar systems absorbing big charge bursts
Quote only
We don't stock Prussian blue cells yet, but we can source them for you.
Request pricing →
Quick reference
The three chemistries side by side
|
Layered oxide |
NFPP |
Prussian blue |
| Energy density |
Highest (89 to 133 Wh/kg) |
Lowest (73 to 95 Wh/kg) |
Middle (~101 Wh/kg) |
| Cold charging |
Down to -20°C on most sizes |
0°C on large cells |
Down to -20°C |
| Voltage window |
Widest (1.5 to 3.9V+) |
Narrower (1.5 to 3.45/3.7V) |
Narrowest (2.0 to 3.6V) |
| Cycle life |
2,000 to 3,000+ |
1,000 to 3,000+ |
2,000+ |
| Best at |
All-round, cold climates |
Long life, stability |
Fast charging, surge power |
| Sizes available |
6 |
3 |
1 |
Read this first
Before you design a pack around sodium-ion
Sodium-ion isn't a drop-in replacement for LiFePO4. LFP sits on a near-flat plateau around 3.2V, but sodium-ion slopes steadily across its whole range. That has a few knock-on effects:
1
Series counts change.
A 4S layered-oxide pack runs from about 6V to 15.6V. That top end is too high for a lot of 12V gear, and much of the bottom end sits below what your inverter will accept. Size the series count to your inverter's input window and expect to leave the bottom 10 to 20% of capacity unused.
2
Your BMS has to know it's sodium.
LFP or NMC presets will undercharge or overcharge. Use a BMS with programmable cell limits and set them inside each cell's rated range.
3
Voltage-based state of charge works well.
The sloped curve is a pain for inverter windows, but it makes voltage a far better fuel gauge than it is on flat LFP.
4
Leave margin.
This is a young chemistry, and independent tests have found real-world capacity retention falling short of spec sheets. Don't run cells at their absolute charge-rate or voltage limits.
Pack hardware
Building with cylindrical cells?
Everything you need to turn loose cells into a finished pack:
Also in our store
4S 18650 Holder
Snap-together cell holders
Pure Nickel Strip
10m roll for spot welding
801D Spot Welder
Pulse welder for cell tabs
Flexible Copper Busbar
200A / 350A insulated
Custom sourcing
Want a cell we don't stock?
Any cell in the chart above can be sourced through us, along with other sodium-ion sizes and formats. We handle the factory side, so you deal with one point of contact from quote to delivery. Send us:
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1The model you want, or your application if you're not sure
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2The quantity
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3Whether you need matched cells, welded tabs or a pre-built pack
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4Your shipping location
We'll come back with pricing, lead time and shipping options.
Contact us about other cell types →
