Thread by @JohnWandersX

CATL’s sodium-ion batteries are about to hit mass production, with full-scale manufacturing set for December 2025 and early BESS pilots starting in 2026. Backed by the world’s largest battery maker, they’re aimed at EVs and short-duration grid storage.

Let’s look at how they stack up against $EOSE zinc batteries, and whether sodium-ion can really take over the BESS market.

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CATL's energy density stands out. Naxtra reaches 175 Wh/kg, nearly twice $EOSE Z3's 70–100 Wh/kg, allowing for more compact EV packs with 500+ km range or efficient grid installations that outperform zinc in density.

This advantage supports applications where space and weight are critical.

2/11

Safety matters. Lithium systems carry thermal runaway and fire risks that demand complex fire suppression, spacing, and insurance premiums. Both sodium and zinc avoid this, using non-flammable chemistries that cut site costs and simplify permitting.

On safety alone, sodium appears to match one of $EOSE zinc’s biggest advantages.

3/11

CATL targets <$50/kWh packs, driven by low-cost materials relative to lithium. $EOSE aims for <$100/kWh installed, but CATL's production goal of 100 GWh/year by 2030 far exceeds Eos's 8 GWh U.S. capacity, securing broad availability.

This combination of cost and scale positions sodium for widespread adoption.

4/11

CATL is already deploying in Chery and Li Auto EVs, plus BYD's 2-4 hour BESS pilots. Strong cold-weather performance and fast charge cycles make it ideal for mobility and short peak-shaving.

On the surface, momentum looks squarely in CATL’s favor.

5/11

Here is where assumptions start breaking.

Sodium excels in 1-6 hour windows, not long-duration. Its 90-95% DoD (how much stored energy can actually be used) and voltage sag mean roughly 30% more capacity is needed for true 12-hour output.

In simple terms: to deliver the same long run, you need more batteries, more inverters, and more balance-of-plant. Eos Z3 runs 100% DoD with stable discharge.

Different chemistries, different jobs.

6/11

For LDES (Long-Duration Energy System), CATL's fast charging benefits EVs, yet $EOSE Z3's aqueous electrolyte enables non-flammable operation with steady voltage over 3-12+ hours without the efficiency losses from cooling.

This supports reliable multi-hour renewable integration.

7/11

In LDES economics, $EOSE avoids oversizing needs, achieving <$100/kWh installed via 45X credits—backed by a $303.5M DOE loan for 8 GWh domestic production by 2026, reducing import vulnerabilities.

The IRA prioritizes such domestic solutions.

8/11

In the broader grid context, 80-90% renewables by 2050 will involve multi-day lulls from low wind or solar. Sodium handles 4-hour peaks effectively, but $EOSE addresses 10+ hour gaps for system reliability.

DOE/NREL project 225-460 GW LDES by 2050;
energy.gov/lpo/articles/s…

California and New York require multi-day capabilities.
formenergy.com/wp-content/upl…

9/11

Overbuilding renewables to cover lulls would require massive excess capacity and curtailment. For LDES, EOSE Z3 offers strong energy delivery for multi-hour to multi-day needs.

CATL's expansion accelerates renewables adoption, creating more long-duration opportunities for $EOSE

10/11

The takeaway: CATL’s sodium-ion is built for scale and speed, perfect for EVs and short-duration BESS. EOSE zinc tech is built for endurance, the backbone of 12+ hour, fire-safe, domestic storage.

As renewables grow, both will thrive. CATL powers the transition. $EOSE keeps it running when the sun sets. ⚡️

11/11
#EnergyStorage #LDES #EOSE

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