Recent news of a breakthrough in solid-state batteries has stirred up a storm in the market. After all, this is widely recognized as the next generation of battery technology, and any development in solid-state battery technology directly impacts the development of lithium batteries; related companies cannot afford to ignore it.
From a technical perspective, just like ternary lithium batteries, lithium iron phosphate batteries, and lithium manganese oxide batteries, solid-state batteries are also divided into three major technical routes.
The three main technical routes for solid-state batteries are: polymer, sulfide, and oxide all-solid-state batteries.
Each technological approach has its advantages and disadvantages. Toyota chose the sulfide route, Ilika chose the oxide route, and the French company Bolloré chose the polymer route.
Toyota was one of the first companies to enter the research of all-solid-state batteries. Comparing sulfide-based and oxide-based batteries: in terms of chemical performance, oxide-based solid-state batteries have higher stability, while sulfide-based batteries are relatively poor. Other indicators, such as conductivity and interfacial impedance, show little difference.
In terms of processing costs, sulfur-based products are more expensive to process, while oxide-based products are less expensive. However, from an integration perspective, sulfur-based products are easier to integrate, while oxide-based products are less so.
From a polymer perspective, it doesn't have an advantage compared to sulfur-based and oxide batteries. However, it does have some advantages, such as ease of integration. The manufacturing cost of polymer solid-state batteries is also a disadvantage. While Bolloré's solid-state batteries are already used in over 2,000 vehicles, they lack advantages in thermal management. Maintaining proper temperature control in polymer solid-state batteries places high demands on thermal management, creating a heavy burden and requiring higher energy and cost resources, thus increasing the difficulty of mass production.
The market considers sulfur-based batteries to be excellent, with sulfide solid-state batteries showing promising performance indicators and demonstration effects after installation. However, Toyota announced in 2017 and 2018 that it would mass-produce all-solid-state batteries in three years, but mass production has not yet commenced. The main reason for this lack of mass production, or rather, the biggest problem, is the relatively poor chemical stability of sulfur-based batteries. This necessitates the addition of numerous protective measures to the production line, and the design also requires more robust protection methods, including encapsulation.
On the other hand, once the battery is manufactured, it is very fragile during operation. Overall, sulfide-based technology is excellent, even surpassing oxide technology in some aspects, but the biggest obstacle to the commercialization of sulfide-based all-solid-state batteries is cost.
Oxide batteries also have technical challenges, but once these challenges are overcome, they become very cost-competitive in terms of commercialization and large-scale production.
Of course, it is too early to tell which technological approach will ultimately prevail.
