Donut Lab’s New Battery Test Misses Key Electrolyte Layer
A UK lab report confirms low lithium levels in Donut Lab's cell, but critics note the electrolyte was excluded from the analysis.
Key points
- Intertek found only 3.4 ppm lithium in a Donut Lab battery sample, supporting claims of a non-lithium chemistry.
- The test excluded the electrolyte layer despite Donut Lab's press release claiming it was included in the analysis.
- The cell previously measured at 409 Wh/kg by VTT, a density difficult to achieve without lithium or sodium.
Donut Lab has released a new independent test result claiming its solid-state battery contains negligible lithium. The report from an Intertek lab in the UK measured only 3.4 parts per million of lithium in the cell material. The Finnish startup is using this data to argue that its technology is neither lithium-ion nor sodium-ion, aiming to end public speculation about its true chemistry.
However, the scope of this analysis is narrow. The test covered only two elements and did not examine the electrolyte layer, a critical component in battery design. Furthermore, nine months after the battery was announced at CES, there is still no production vehicle operating with this cell, leaving its real-world performance unverified by drivers or third-party automotive tests.
Limited scope of the laboratory test
The Intertek report focused exclusively on quantifying lithium and sodium using a specific analytical method. It did not test for other potential active materials like potassium, magnesium, or zinc. Consequently, the result proves the absence of two specific elements but offers no positive identification of what the battery actually contains. Donut Lab has not disclosed the full chemical composition, describing it only as using affordable and secure materials.
There is also a discrepancy regarding the electrolyte. Donut Lab’s press release stated that the electrolyte between the anode and cathode was included in the sample. The Intertek report contradicts this, stating three times that only the anode, cathode, and current collector pieces were analyzed. Since the electrolyte is a primary location for active ions in battery cells, excluding it from the test limits the conclusiveness of the findings.
Sample origin and revision history
The sample was not opened by the laboratory. Donut Lab disassembled the cell itself and delivered the pieces in a torn-down condition to Intertek. The report labels the sample simply as Pouchcell Cell 1, without explicitly linking it to the specific V1.5 cell that underwent energy density testing. This lack of direct identification in the document raises questions about the precise lineage of the material tested.
The document also underwent multiple revisions within a short period. The initial report was issued on September 17, with subsequent versions on September 21 and 22 updating sample descriptions and experimental wording. While minor edits are common, the frequency of changes for a short report containing a single results table has drawn attention from industry observers and analysts.
Energy density claims remain unexplained
The near-zero lithium result conflicts with the energy density figures previously reported by VTT, which measured 409.3 Wh/kg on a Donut cell. This value is comparable to advanced silicon-anode lithium-ion batteries, which rely heavily on lithium. It is difficult to reconcile a chemistry lacking significant lithium or sodium with such high energy density, as no other known rechargeable system currently achieves these levels in a real cell.
Electrek notes that the fast-charging and cycle-life claims associated with Donut Lab’s technology might align more closely with supercapacitor or hybrid capacitor designs. These systems can achieve high power output without relying on lithium or sodium. However, they typically struggle to reach the high energy density required for long-range electric vehicles, creating a technical paradox that the new test does not resolve.
