An analytical article published by CleanTechnica on September 4, 2026, reported that new tests of Donut Lab’s battery supported the company’s claim that it is an all-solid-state battery, recording a gravimetric energy density of 409 Wh/kg and a volumetric energy density of up to 804 Wh/L. The results follow the battery’s unveiling at CES 2026, amid public skepticism that these figures could be achieved with a viable solid-state battery.
The material does not provide a specific chemical composition for the cell, nor does it present the full measurement methodology or testing conditions in detail. The figures should therefore be treated as results reported by the source from Donut Lab’s tests, rather than as a final independent validation of the technology.
What did the battery tests rely on?
The analysis focuses on two characteristics that it says support the battery’s solid-state structure. The first is the possibility of manufacturing it in a bipolar configuration, in which cells are stacked inside the pack and electrically connected in series. The source argues that this arrangement is not practically compatible with a shared liquid electrolyte, because the liquid could move between the cells and disrupt the required ion pathway, whereas the solid electrolyte remains in place between the cathode and anode.
The second piece of evidence is the disassembly of the cell. The internal examination showed repeated layers electrically connected through the stack, without internal mechanical insulation between the layers. According to the analysis, the bipolar structure could reduce resistance and the materials required for the electrodes, and reduce the number of modules and external connectors in the pack, potentially increasing energy density at both the cell and pack levels.
Safety is not the only measure of progress
The source also mentions nail-penetration tests at a terminal voltage of 12 volts. According to the presented results, there was no fire, smoke, or explosion, and no significant temperature increase occurred. The article compares this with the behavior of NMC cells, which may produce higher flames and heat in the same test, and with LFP and sodium-ion cells, whose performance it described as less impressive.
The analysis also says that the earlier test indicated the battery’s bipolar nature because the terminal voltage exceeded 12 volts and different voltages appeared when the number of layers was changed. However, the safety test alone does not establish every aspect of performance, and the absence of fire does not determine the cell chemistry or its long-term commercial suitability.
Manufacturing may matter more than chemistry
The article highlights a less prominent aspect of the discussion: the production process. The source links Donut Lab’s design to the possibility of using nanomaterial pastes and printing, instead of some of the equipment and controlled environments required to manufacture lithium batteries with liquid electrolytes. According to the material, the company says its batteries do not require a formation stage, the initial charging stage that creates the interfacial layer between the electrolyte and electrode and takes up space and time while consuming operational resources.
This approach raises the possibility of reducing factory complexity and costs, particularly if solvent-containment rooms, vapor-recovery systems, and storage facilities associated with the formation stage can be avoided. The source gives an estimate that a 1-gigawatt-hour factory could cost $1 billion under conventional models, while a solid-state printing process could be an order of magnitude less expensive. However, this point remains an estimate and analysis, not a verified financial result for a commercial production line operated by Donut Lab.
Why does this news matter?
If the results are confirmed in independent tests and at production scale, the combination of a density exceeding 400 Wh/kg, a bipolar solid-state structure, and manufacturing that relies less on costly rooms and stages could shift the discussion from whether solid-state batteries can be manufactured to whether their production can be scaled. This would affect electric-vehicle manufacturers, battery suppliers, and investors in conventional cell factories.
However, the material itself identifies what remains unresolved: cycle life and energy retention at −30°C. The lack of a specified chemistry and the absence of complete details about measurement conditions also leave important questions about whether the results can be compared with other products. The most cautious reading is that the announced tests provide strong support for the claims of a solid-state structure and high performance, but they do not yet establish comprehensive commercial readiness or superiority under all operating conditions.