#1 All-solid-state batteries are a revolution in electricity storage
Partially true: They have been of interest to scientists and manufacturers for decades
The discovery of the phenomenon of ionic conduction in solids dates back to Michael Faraday in the 19th Century. In the 1980s, French and American scientists developed the first thin-film all-solid-state batteries, but interest waned because the market was not there and it was impossible to switch to thick films without affecting performance due to the lack of ionic conductors. In 2011, a patent filed by Japanese scientists for a new type of all-solid-state ionic conductor gave the field a major boost1, leading led to an explosion in research and interest from manufacturers – namely Toyota. Today, there are research laboratories around the world are working on this topic.
False: Some theoretical advantages have not been proven in practice
All-solid-state batteries work in a similar way to conventional lithium-ion batteries. The differences are that the liquid electrolyte in Li-ion batteries is replaced by a solid inorganic electrolyte and the graphite in the anode is replaced by metallic lithium. These batteries have generated a lot of enthusiasm due to two advantages: increased safety due to the absence of flammable liquid electrolyte and increased energy density performance. In theory, they are not affected by the problem of dendrites, the metal deposits that degrade batteries.
Unfortunately, in practice, it was soon apparent that the dendrite problem still existed. Furthermore, during manufacture and recharging, high pressures must be applied to ensure good contact between the different parts of the battery. Finally, the safety aspect is disappointing, as these batteries do not really outperform Li-ion batteries.
#2 All-solid-state batteries are ready to be commercialised
Partially true: Hybrid batteries are already on the market
Manufacturers’ impatience has led to the development of an alternative technology: hybrid batteries. In practice, part of the solid electrolyte is replaced by a liquid, an ionic gel or a small amount of polymer. For example, Prologium markets solid/gel hybrid batteries, manufactured in a gigafactory in Taiwan. Hybrid batteries with an “almost”-solid electrolyte have been another avenue explored for two decades, and Welion already markets them. Hybrid batteries have the advantage of being produced using the same manufacturing processes as Li-ion batteries. On the other hand, their safety and performance are reduced compared to all-solid-state batteries.
False: No all-solid-state batteries are commercially available
There are no all-solid-state batteries on the market today. Several companies are working on them, but their success depends on the degree of hybridisation: the closer the battery is to being all-solid-state, the longer it will take to reach the market. Many avenues are being explored to achieve this goal: new, more ductile materials for the anode, requiring less pressure than lithium metal; better ionic conductors; anode-free batteries, etc.
#3 Once all-solid-state technology reaches maturity, Li-ion batteries will disappear
False: Manufacturing processes are too expensive to dethrone Li-ion
It would be impossible for Li-ion batteries to disappear with the arrival of all-solid-state technology. Li-ion technology, like its predecessor lead-acid technology, will be around for decades if not centuries. For certain uses, such as stationary batteries, all-solid-state technology offers no advantages. The main obstacle to the commercialisation of all-solid-state batteries is production. The need to apply significant pressure represents a high economic cost. Of course, there are already manufacturing processes that include a compression phase, such as fuel cells, but the production line is completely different from that used for batteries. Manufacturing all-solid-state batteries in current battery factories would require a complete overhaul of production lines. This is a far cry from the scale of a gigafactory…
Uncertain: When their cost falls below that of Li-ion, the automotive industry could turn to all-solid-state batteries
For certain uses, it’s possible that Li-ion batteries could become obsolete. The theoretical performance of all-solid-state batteries shows greater power and energy density in a smaller volume. This is of great interest to the automotive and drone industries. However, it remains very difficult to make batteries that are cheaper than Li-ion today. All-solid-state batteries will not replace Li-ion batteries for at least two decades, as their cost must fall below that of Li-ion batteries. If research were pooled on an international scale, a lot of time could be saved on these developments.
