Colloquium Series: Emanouil Glynos (FORTH Crete)

Nanostructured Polymer Particles for Next Generation Energy Storage

Climate change, pollution and declining fossil resources are overwhelming challenges to humankind. Gaseous emission from burning fossil fuels pollutes the air in large modern cities creating a global warming with alarming climate changes. These concerns have led to national initiatives to reconsider the use of alternative energy sources such as solar radiation, wind, and waves. However, the intermittence of these resources (their variability in time and wide distribution in space) requires high energy storage systems. To this end, secondary batteries based on lithium metal anodes are the most sought-after candidates for next-generation storage systems since they can store a large amount of energy per unit mass or volume. However, unstable electrodeposition and uncontrolled interfacial reactions occurring in conventional liquid electrolytes cause unsatisfying cell performance and major safety concerns.
Solid polymer electrolytes (SPEs) could be a “real game-changer” as they hold the promise to solve most of the problems of liquid electrolytes. SPEs are inherently safe, nonflammable, and compatible with lithium metal anodes. Despite the considerable research effort in SPEs, the primary challenge is the development of solid materials with good mechanical properties without sacrificing ionic-conductivity. This talk will provide evidence that the use of complex macromolecular architectures holds the promise for the development of nanostructured materials with precise/desired morphologies that promotes SPEs properties to levels and temperature range not accessible before by conventional linear macromolecular systems. In particular the use of novel polymer nanostructured nanoparticles will be introduced as additives to liquid electrolytes for the synthesis of SPEs that exhibit an unprecedented combination of high modulus and ionic conductivity. The nanoparticles are composed of high functionality mikto-arm star copolymers in which stiff insulating arms complement ion conducting arms. Because of their molecular design and their colloid-like structure, the materials constitute the first example of all-polymer nanostructured materials where each and every building block is a nano-sized polymeric nanostructured “molecular material”. It will be demonstrated that the final/desired morphology and phase dimensions of the SPEs may be precisely controlled as is encrypted within the macromolecular characteristics and the chemical composition of the “nanoparticles”. As the synthesis of mechanical robust electrolytes with superior ion-conductivity has been the subject in a wide variety of solid-state electrochemical devices, this approach may significantly contribute to other applications, beyond lithium metal batteries, such as anion exchange membranes for fuel cells, efficient active layers in dye-sensitized solar cells, electrochromic devices and water desalination systems.