According to the official website of the University of Cambridge on the 26th, the school's researchers wrote in the latest issue of Nature that they have recently determined that bismuth tungsten oxide has a higher lithium pass rate and can be used to develop batteries that can be charged faster. Moreover, the physical structure and chemical behavior of the oxides help them gain insight into how to build safe, ultra-fast rechargeable batteries.
The battery consists mainly of three components: positive electrode, negative electrode and electrolyte. When the battery is charged, lithium ions flow out of the positive electrode and reach the negative electrode through the crystal structure and electrolyte, where they are stored. The faster the process occurs, the battery is charged. The faster the speed.
When looking for new electrode materials, researchers often try to make the particles smaller, but it is difficult to make a practical battery containing nanoparticles: the electrolyte will generate more unnecessary chemical reactions, so the battery life is not long, and The manufacturing cost is also high. The tantalum tungsten oxide used in the latest research has a hard and open discharge structure that does not capture the intercalated lithium and is larger in size than many other electrode materials.
The first author of the study, Kent Griffith, a postdoctoral fellow at the University of Cambridge, explained: 'Many battery materials are based on the same two or three crystal structures, but these tantalum tungsten oxides are fundamentally different. Oxides through oxygen' The pillars ' remain open, allowing lithium ions to pass through them in three dimensions, which means more lithium ions can pass through them, and at a faster rate. The measurement also shows that the speed at which lithium ions pass through the oxide is better than The electrode material is several orders of magnitude higher. '
In addition to high lithium mobility, tantalum tungsten oxide is also easy to manufacture. Griffith says: 'Many nanoparticle structures require multiple steps to synthesize, but these oxides are easy to manufacture and do not require additional chemicals or solvents. '
At present, most of the negative electrodes in lithium-ion batteries are made of graphite. Graphite has a high energy density, but when charged at a high rate, it tends to form a slender lithium metal fiber called 'dendritic', which causes a short circuit. And caused the battery to catch fire and even explode.
Griffiths said: 'In high-rate applications, safety is more important than any other operating environment. For fast-charging applications that require safer graphite alternatives, these and other similar materials are definitely worthy of attention. '
