From solid-state batteries (SSB), we promise a significant improvement in the properties of today’s batteries, especially higher safety thanks to the solid electrolyte. However, with further advances in the field of battery development, other features than just safety could be improved. Company Xiaomi presented just such a thing. She showed solid-state batterywhich achieves a very high energy density over 1000 Wh/l, which is a significant increase compared to today’s values, which for Li-Ion NMC reach approx. 750 Wh/l. In principle, the density would increase by about a third. We probably wouldn’t expect smaller batteries in phones, but rather filling the same volume as today with a battery with a higher capacity (and longer endurance).
What exactly does that mean? E.g. Xiaomi 13 has a battery with a capacity of 4500 mAh, however, in the case of the solid-state version, according to Xiaomi, a SSB battery with a capacity of 6000 mAh could fit here in the prototype. For some strange reason, many associate SSB with worse performances at lower temperatures, which was true for some early prototypes of some mixtures, but it certainly cannot be generalized and applied to all SSBs (it depends on the specific combination of anode, cathode mixture and the type of electrolyte itself and others details). In the case of Xiaomi, it is the opposite.
According to him, classic batteries at very low temperatures suffer from the fact that the electrolyte solidifies and the conductivity of lithium ions decreases by up to 60%. However, with SSB from Xiaomi, their performance is 20% higher compared to standard batteries at a temperature of -20 °C. This can mean many things. If Xiaomi is talking about percentage points, then it would mean a drop of 40%, which is still a lot, but it would still be a much better result. If they are talking percentages, then it would be 20% to the 40% of the rest, a drop to 48% (in other words, not a drop of 40%, but a drop of 52%). And maybe Xiaomi is also talking about something completely different with an appropriate choice of words to confuse us.
Last but not least, safety is increased. The solid electrolyte prevents dendrites from penetrating, which can cause a short circuit and battery failure, leading to a fire in the worst cases. Xiaomi also successfully tested the battery puncture, which did not lead to any explosion or anything like that. However, we still have no idea when (or if) the new batteries will appear, and their mass energy density was not mentioned either. It is possible that batteries take up less space per unit of energy (have a higher volumetric energy density), but at the same time they may also be heavier per unit of energy (have a lower mass energy density) and thus be heavier than today’s batteries.
