Electrolyte research improves efficiency of batteries and fuel cells

According to researchers at the Faculty of Applied Sciences at TU Delft, the better the characteristics of an electrolyte – the material between two electrodes – the more efficiently the battery or fuel cell works. Electrolyte is usually a liquid, but has to be well enclosed and takes up a relatively large amount of space. However, the conductivity in solid matter electrolytes is inferior. PhD student, Lucas Haverkate, said: "In a solid matter you have a network of ions, in which virtually every position in the network is taken. This makes it difficult for the charged particles (protons) to move from one electrode to another. It's a bit like a traffic jam on a motorway. What you need to do is to create free spaces in the network." According to Haverkate, by adding 7 to 50nm nanocrystals of Titanuim Dioxide, protons become attracted and this creates more space in the network. The nanocrystals are mixed in the electrolyte with a solid acid which 'delivers' the protons to the crystals. "The addition of the crystals appears to cause an enormous leap in the conductive capacity, up to a factor of 100," noted Haverkate. Fellow PhD student, Wing Kee Chan carried out measurements on the electrolyte material by sending neutrons through the material . The way in which the neutrons are dispersed makes it possible to deduce certain characteristics of the material, such as the density of protons in the crystals. Haverkate said that it is the first time that measurements have been taken of solid material electrolytes in this way, and on such a small scale. "The fact that we had nuclear research technologies at the Reactor Institute Delft at our disposal was tremendously valuable," he explained. Further material combinations are being tested for more stability. Professor Fokko Mulder, pictured, who is Haverkate and Chan's PhD supervisor, said that at this stage the research was focused on acquiring a fundamental understanding and a useful model, rather than finding out what the most suitable material is. "It is important that we identify the effect of nanocrystals, and give it a theoretical basis," he said. "I think there is great potential for these electrolytes. They also have the extra benefit of continuing to function well over a wide range of temperatures, which is of particular relevance for applying them in fuel cells."