Christopher Mims writes the weekly KEYWORDS technology column for The Wall Street Journal. Last week he interviewed our CEO, Harrold Rust, for his latest column, The Battery Boost We’ve Been Waiting for Is Only a Few Years Out (you may need a WSJ subscription to access the full article).
The column opens with the following.
The batteries that power our modern world—from phones to drones to electric cars—will soon experience something not heard of in years: Their capacity to store electricity will jump by double-digit percentages, according to researchers, developers and manufacturers.
The column focuses on silicon and silicon composite anodes for lithium-ion batteries.
Typically, anodes in lithium-ion batteries are made of graphite, which is carbon in a crystalline form. While graphite anodes hold a substantial number of lithium ions, researchers have long known a different material, silicon, can hold 25 times as many.
The column quotes George Crabtree, Ph.D., director of the Joint Center for Energy at the University of Chicago Argonne Laboratory, that in any present commercial battery, “silicon is at most 10% of the anode.” He also discusses the challenges of producing an anode with a greater percentage of silicon in the anode.
The column describes different approaches taken by companies to overcome silicon anode challenges. Regarding Enovix, the column states:
Enovix, whose investors include Intel and Qualcomm, has pioneered a different kind of 3-D structure for its batteries, says CEO Harrold Rust. With much higher energy density and anodes that are almost pure silicon, the company claims its batteries would contain 30% to 50% more energy in the size needed for a mobile phone, and two to three times as much in the size required for a smartwatch. The downside: production will require a significant departure from the current manufacturing process.
In fact, about 65% of our manufacturing process is common to the current battery industry. This includes using a complete range of commercial cathode materials. We differ in the process to produce our patented 3D cell structure, the key to increasing energy density by accommodating a 100% silicon anode and improving the spatial efficiency (ratio of active to inactive materials) of a lithium-ion battery. For this, we leverage mature processes and equipment from the solar and electronics assembly industries.
The column also states that, “The first commercial consumer devices to have higher-capacity lithium-silicon batteries will likely be announced in the next two years.” We agree.