A Li-ion battery is a device that stores energy by allowing lithium ions to move from one side of the system to the other, releasing energy as electricity in a controlled manner. The battery forms a significant proportion of the total cost of an electric vehicle. One of the largest challenges facing electric vehicle manufacturers is to bring the cost down, while safely increasing the amount of energy stored. Technologists are finding that traces of new compounds, even accidental contaminants, can alter the properties of battery materials to improve parameters such as energy density. Thanks to increased understanding of this complex chemistry and the physics involved, small, steady improvements in Li-ion batteries are driving forward the accessibility of electric vehicles. Changing the materials used to make the anode from graphite to something else, is slated to be the next major advance. Silicon anodes have the potential to store more lithium ions than graphite, making them more energy-dense. Specialist battery developer Enovix has created safer, more energy-dense Li-ion batteries for small electronic devices with a patented, porous silicon anode. The Enovix manufacturing process is also a novel one for batteries, adopting the photolithographic mask and etch techniques used to create solar cells. Combined, this approach delivers an energy density of 1.5 to 3 times that of conventional Li-ion batteries for wearable devices, depending on cell size and thickness. Other companies are also looking at the possibilities of a high-energy silicon anode.
