The test was conducted by multinational product testing and certification company Intertek, which analysed the internal structure and elemental composition of Donut Lab’s next-generation battery cell.
“When we unveiled the Donut Battery at CES, we stated that it is made from widely available, affordable and geopolitically secure materials” said Marko Lehtimäki, CEO of Donut Lab. “However, we did not disclose the battery’s exact chemistry. Some have speculated that it is a lithium cell, while others are convinced it relies on sodium-based chemistry. We wanted to put this speculation to rest with an independent test demonstrating that it is neither a lithium-ion nor a sodium battery.”
The test was conducted at Intertek’s laboratory in the UK, where all the active components of the cell were sent for analysis. These included, for example, the current collectors, the anode that enables the oxidation reaction, the cathode that enables the reduction reaction, and the electrolyte situated between them.
The samples were dissolved in nitric acid and analysed using a standardised ICP-OES method accredited by the United Kingdom Accreditation Service (UKAS). This is a sensitive method capable of detecting elements present in extremely minute trace amounts. In the process, plasma breaks the sample down into individual atoms, and each element present emits light at its own characteristic wavelengths.
Lithium was found in the battery cell at a concentration of 3.4 parts per million (ppm). For comparison, the lithium content in lithium-ion batteries is measured in percentages, meaning tens of thousands of times more lithium than in the Donut Battery. In practice, the level detected by Intertek is one that would be found in almost any material.
The battery contained 632 parts per million (ppm) of sodium, which is explained by the fact that sodium is found everywhere. In a sodium-ion battery, the active material would contain 50–100 times more sodium than in the Donut Battery.
“In practice, it is not even possible to build a functional battery with such small amounts of active materials, which demonstrates that the Donut Battery is composed of materials other than lithium or sodium” added Ville Piippo, CTO at Donut Lab.
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