Martin Mika is an Associated Professor of Chemistry and Technology of Inorganic Materials at the Department of Glass and Ceramics at the University of Chemistry and Technology in Prague. Prior to this he held an Associated Western Universities/AWU Visiting Scientist Fellowship (awarded 1996) at the Pacific Northwest National Laboratory/PNNL in Hanford/Richland, USA, and a NATO Research Fellowship (awarded 2007) at the Institute of Applied Physics/IFAC-CNR in Florence, Italy. Currently, he is the principal investigator of the project “Modulators for free-space optics” funded by the Technology Agency of the Czech Republic. His research interests are in photonic glass; fast ion-conducting glass for batteries; inorganic/organic membranes for fuel cells; high-strength foam glass; x-ray optics for space telescopes; glass for nuclear waste immobilization; phase equilibria and electrochemistry of glass-forming melts and biomass combustion. He earned his Ph.D. degree in Chemistry and Technology of Inorganic Materials from the University of Chemistry and Technology in Prague. His research group consist of 2 assistants, 11 students and a technician. In 1986 he was awarded the first price at the International Student Conference in Prague; in 2003 he was awarded the Vittorio Gottardi Award from the International Commission on Glass (ICG); in 2013 he was awarded the Preciosa Award for his pedagogical achievements and in 2014 he was awarded the Czech Glass Society Award. He is a member of the Czech Glass Society and the ICG Technical Committee TC10 “Optical Properties of Glass and Coated Products”.
Glass nanofibres for a new generation of high-capacity solid state batteries
Martin Mika*, Frantisek Lahodny & Jan Baborak
Department of Glass and Ceramics, University of Chemistry and Technology, Prague, Technicka 5, 16628 Prague, Czech Republic
The rising concentration of combustion-driven vehicles in urban areas poses serious threats to human health by pollution from nitrogen oxides and micro- or nanoparticles known as particulate matter (PM). Long-term exposure to these toxic substances has been linked to serious health problems, including depression, diabetes, dementia, Alzheimer’s and Parkinson’s. Legislation and the increasing demand for more ecological cars have persuaded many car producers to focus on the development of a new generation of electric vehicles (EV) that have the potential to replace diesel and petrol cars. Such cars must be competitive in terms of driving range, energy recharging rate and price. In this sense, new batteries for EV must be able to deliver high energy and current densities. Such demands cannot be met by the current generation of Li-ion or Li-polymer batteries that typically contain an organic electrolyte (liquid or polymer) between rigid electrodes made of polycrystalline material. When these classical batteries are fast charged or discharged, the high flow rate of charge carriers, such as Li+or Na+, forms metallic dendrites on the negative electrode. As the process goes on, the dendrites continue to grow through the soft electrolyte until they reach the opposite electrode and short circuit the whole battery cell. As the cell heats up, the organic electrolyte decomposes and forms gasses that pressurize the cell and can even lead to an explosion. Here we propose a new approach, the development of an all solid secondary battery based on a sufficiently flexible electrolyte and electrodes. This represents a new type of high capacity all-solid-state battery in which the bulky crystalline materials are substituted with thin glass layers. Amorphous glass materials can be easily deposited and nanostructured to obtain gradient functional layers exhibiting much higher surface-to-volume ratios. We believe that such an approach can efficiently prevent the growth of dendrites, thereby keeping the electrodes separate and avoiding their short circuiting. To achieve this, we melted fast ion-conducting (FIC) glasses in a LiI-Li2O–P2O5–V2O5MoO3–WO3 system and tested them at temperatures ranging from -20 to 150 °C. Using electrochemical impedance spectroscopy and chronoamperometry, the glass ionic and electronic conductivities were determined as 2-10 S/m and 3-8·10-6 S/m, respectively. The prepared glasses were also characterized using optical and electron microscopy, simultaneous thermal analysis, infrared and Raman spectroscopy, and nuclear magnetic resonance. Particular attention was paid to the effects of the composition and preparation procedure on the electrochemical properties of the glass. Having optimized their electrochemical properties, we electrospun a TEOS polymer with the FIC glass nanopowders to form a thin nanofibrous layer with sufficient conductivity for use as the electrolyte and electrode. The performance of this battery cell was evaluated using cyclic voltammetry and over multiple long-term charge/discharge cycles. Collectively, our results indicate that the developed FIC glass nanofibers have potential for the construction of new-generation high-capacity batteries to power plug-in electric cars.