Researchers at MIT and Samsung, and in California and Maryland have found that the use of solid-state electrolyte in place of liquid electrolyte in batteries can provide a 20 – 30 per cent improvement in power density, with a corresponding increase in how long a battery of a given size could power a phone, a computer, or a car. According to the research, solid-state electrolyte holds advantages as there’s virtually no degradation reactions left, which implies that such batteries could last through ‘hundreds of thousands of cycles.’ Adding further, the release states that the use of solid electrolyte, rather than liquid electrolyte, exhibited improvement in both device lifetime and safety, while providing a significant boost in the amount of power stored in a given space.
A solid-state battery is a battery that has both solid electrodes and solid electrolytes. As a group, these materials are very good conductors of ions, which is necessary for good electrolyte and electrode performance, and are essentially insulating toward electrons, which is desirable in electrolytes but undesirable in electrodes. The high ionic conductivity minimises the internal resistance of the battery, thus permitting high power densities, while the high electronic resistance minimises its discharge rate, thus enhancing its charge retention.
According to the researcher Ceder, the use of solid state electrolyte could be ‘a real game-changer,’ as it can almost create a perfect battery by solving most of the remaining issues in battery i.e. lifetime, safety, and cost. The research team was able to analyse the factors that make for efficient ion conduction in solids, and home in on compounds that showed the right characteristics. The initial findings focused on a class of materials known as superionic lithium-ion conductors, which are compounds of lithium, germanium, phosphorus, and sulfur, but the principles derived from this research could lead to even more effective materials, the team says.
“This solid-state electrolyte has other, unexpected side benefits. While conventional lithium-ion batteries do not perform well in extreme cold, and need to be preheated at temperatures below roughly -20 degrees Fahrenheit, the solid-electrolyte versions can still function at those frigid temperatures,” said Gerbrand Ceder, a visiting professor of materials science and engineering.