alt Hacker NewsFirst report for Donut lab battery is out. Here is the TLDR
Specs
26 Ah nominal capacity at 1C discharge rate
94 Wh nominal energy with 3.6V nominal voltage
Operates within 2.7V – 4.15V recommended range (max charging to 4.3V)
5C charging (130A): 0-80% in ~9.5 minutes, 0-100% in ~13.5 minutes
11C charging (286A): 0-80% in ~4.9 minutes, 0-100% in ~7.3 minutes
Successfully delivered 98.4-99.6% of charged capacity even after extreme 11C charging
Tested with both one-sided and two-sided heat sinks to simulate real-world conditions
With dual heat sinks: Peak temps of 47°C (5C) and 63°C (11C) — well within safe limits
With single heat sink: Reached 61.5°C (5C) and up to 89°C (11C) — still functional but approaching thermal limit
Energy density: No weight and volume was mentioned
Cycle life: VTT ran only 7 test cycles total.
Cost Claims: Nothing about cost is mentioned
Material Claims: No chemical analysis or materials analysis.
Extreme Temperature Performance: No cold weather testing. No high-temperature testing.
No abuse testing: No nail penetration, no overcharge, no short-circuit, no crush tests.
Replies
It’s good to know that it does at least perform about as well as current conventional batteries. The energy density and cycle life were the really off-the-wall claims. It’s exciting to hear that they’re continuing to test, can’t wait for more third party results!
Edit: Reading the report, they talk about “charge capacity” (Amp hours in/out) efficiency of 98.4% to 99.6%, but this seems potentially misleading. The actual charge energy efficiency is more like 90%.
> Successfully delivered 98.4-99.6% of charged capacity even after extreme 11C charging
Note the Wh numbers for discharge vs. charge energy.
> Discharge capacity Charge capacity Discharge energy Charge energy
> Cycle 1 26.109 Ah 26.159 Ah 91.021 Wh 100.793 Wh
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> Energy density: No weight and volume was mentioned
Note that the report includes some photos of the battery, so we can assume that it's not, like, several orders of magnitude larger than what they advertised.
EDIT: Honestly, I'm pretty excited. Even if their promises on cost and materials don't pan out and the lifetime turns out to be terrible, what they've just demonstrated is already a game-changer.