Over the past few years, the world of battery manufacturers and electric car makers has been abuzz with interest in " all-solid " batteries, as have our institutions, judging by their roadmap, which predicts that this technology will reach maturity by 2030. A large number of SMEs are springing up, and numerous industrial partnerships are being set up to position themselves in this highly lucrative market. This craze has even spread to Europe and France, given the financial support given to the Taiwanese company PROLOGION for the construction of a gigafactory to develop so-called " all-solid batteries ". This technology could ideally i) outperform conventional Li-ion batteries in terms of safety, but also ii) enable higher volumetric energy densities thanks to bipolar configurations and the use of metallic Li.
However, enthusiasm is beginning to wane as awareness grows of the recurring difficulties associated with the interfaces forming between the solid electrolyte (thiophosphate) and the positive electrode (lamellar oxide) and also with the negative electrode (Li), not to mention the pressure requirements associated with its operation. Isn't the all-solid-state battery becoming a " Graal " that's slipping away ?
In its own way, this lecture will attempt to be pragmatic by assessing the current intense research in the field, while distinguishing between reality and hype. It will place this technology in its historical context, recalling that it first saw the light of day in the 1970s, without much success, before gaining new impetus thanks to the discovery of new ionic conductors in 2013 (Li10GeP2S12). Since then, it has captured the interest of all the world's battery research centers, without exception. This craze has led to numerous advances in both the design of new ionic conductors and the engineering of interfaces via coating methods or the creation of heterostructures, which will be reviewed in the lecture. The move to all-solid state has also led to innovations in both characterization techniques and cell assembly, notably in lowering pressure and enabling the use of a Li anode, which will be mentioned.
Despite this, the impatience of the industrial world is growing, leading them to favour all-solid-state hybrid technologies based on the use of polymers, gels, ionogels and even liquids. It goes without saying that this drift leads to compromises in performance and raises questions about the final added value of all-solid technologies, which will be discussed. Lectures will be followed by seminars on analytical techniques (F. Kanoufi), mechanical properties (C. Laberty), the design of new materials (F. Kanoufi, C. Masquelier, M. Rosseinsky) and fluorination processes (M. Dubois). Two speakers from the world of industry (R. Bastien) and the world of investors (G. Bonhomme) will close this series of lectures.