A new glas-like Lithium could open up millions of possibilities for battery makers

Scientists at the University of California San Diego and the Idaho National Laboratory first glimpsed the non-crystalline "glassy" lithium that forms in the earliest stages of lithium charging. During such stages, slow, low-energy charging causes the electrodes to collect the atoms in a disordered manner, which improves the charging behavior. This had never been seen before. In a study published in the journal Nature Materials, the researchers say these results could help fine-tune recharge approaches to increase battery life and make vitreous metals for other uses. To conduct their experiment, scientists wondered whether the charging pattern in lithium batteries is influenced by the earliest accumulation of the first few atoms, a process known as nucleation. Nanostructural lithium atoms (blue) that are deposited on an electrode (yellow) while the battery is charging. (Image courtesy UC San Diego). The basis for their question was the fact that the way in which lithium atoms deposit on the anode when recharging high-energy batteries can vary from one recharge cycle to the next, resulting in irregular charging and a shortened battery life. For their observations, the scientists combined images and analyzes from a powerful electron microscope with liquid nitrogen cooling and computer modeling. Cryostat electron microscopy allowed them to see lithium metal "embryos" forming, and the computer simulations helped them explain what they were seeing. They discovered that certain conditions created a less structured form of lithium that was more amorphous (like glass) than crystalline (like diamond). During recharge, vitreous lithium embryos remained amorphous (like glass) rather than crystalline (like diamond) throughout growth. When examining the conditions that favored vitreous nucleation, the team found that it was able to make amorphous metal under very mild conditions at a very slow rate of charge. This result was inconclusive, as the experts assumed that slow deposition rates would allow atoms to find their way into an ordered, crystalline lithium. However, modeling work did explain how reaction kinetics drives the vitreous formation. To confirm these results, the scientists created glass-like shapes of four other reactive metals that are attractive for battery applications. According to a media report from the university, the results of this study could help achieve the goals of the Battery500 Consortium, an initiative by the Department of Energy that funded the research and which aims to produce commercially viable batteries for electric vehicles with a cell-level specific energy of 500 Wh / kg to develop.