Ryoji Kanno

Professor Director, Research Center for All-Solid-State Battery Institute of Innovative Research Tokyo Institute of Technology

Batteries are a hot topic in today’s world. Since their original invention by Volta over 200 years ago, many types of batteries have been developed and adopted for practical use, revolutionizing the world around us. The roster of useful battery architectures, which in earlier generations featured such stalwarts as lead-acid and zinc-carbon cells, was extended in 1991 by the arrival of lithium-ion batteries (LIBs), which are now widely deployed as power sources for devices such as video cameras, cellular terminals, smartphones, and even electric vehicles. Unfortunately, the reality is that today—some 30 years after the advent of lithium-ion batteries—we are only just beginning to understand how to use these devices in vehicles—a state of affairs that testifies to the agonizingly slow pace of progress in battery technology.

Just as lead-acid cells and similar workhorse devices furnished trustworthy foundations for daily life throughout the first 150 years of the battery era, lithium-ion batteries are widely expected to play a key role as energy-storage devices enabling the society of the future. But can this technology—which is already beginning to exhibit signs of approaching fundamental performance limits—truly remain viable throughout the next 50 to 100 years? The possibility that it may not motivates efforts to develop the next generation of energy-storage devices. Among the various candidate technologies that have been proposed for next-generation batteries, at Tokyo Tech’s Research Center for All-Solid- State Battery we focus on one particular approach: the all-solid-state battery, in which the electrolytic solution used in conventional lithium-ion batteries is replaced by a solid electrolyte, yielding a fully solid-state battery with no liquid components. The crucial challenge here is the design of the electrolyte itself, which must be a solid material through which ions can diffuse at high speeds. In 2011 we were thrilled to discover that lithium, phosphorus, sulfur, and germanium could be combined to yield a novel solid material—Li10GeP2S12—through which lithium ions move even more rapidly than through liquids at room temperature (Figure 1). We successfully demonstrated that all-solid-state batteries with solid electrolytes made from such materials not only achieve more than twice the output performance of conventional liquid-electrolyte LIBs, but also retain outstanding energy-storage properties over an extremely wide range of operating temperatures, from -30 to 100°C and above. The years since this breakthrough have seen vigorous efforts by researchers at many institutions to deploy all-solid-state batteries for practical applications.

 

If you were interested in this speaker’s availability and fee, please contact at here.

＜video＞

■Material Development for Novel Energy Devices - Kanno & Suzuki Laboratory

■All-solid-state batteries - Tokyo Tech Research