A Stanford University team of researchers, including Nobel Prize winner and former U. S. Secretary of Energy Steven Chu and Yi Cui, long familiar to CAFE Blog readers, are using carbon nanospheres to coat lithium electrodes and help them resist expansion problems that formerly fractured them, and to keep elements in the battery’s reactive electrolytes from dissolving them. This approach has enabled the team to craft a pure lithium anode, with all the promise of high energy density that such an electrode holds. It’s also stable, a boon to longevity for these cells. As reported in the news release By Andrew Myers for the Stanford Engineering School, “’Of all the materials that one might use in an anode, lithium has the greatest potential. Some call it the Holy Grail,’ said Cui, a professor of Material Science and Engineering and leader of the research team. ‘It is very lightweight and it has the highest energy density. You get more power per …
That’s No Yolk!
Dr. Cui is at it again! In a seemingly endless stream of announcements, his work with silicon anodes keeps promising improvements in battery capacity and longevity. The Stanford professor and his team, Stanford’s National Accelerator Laboratory (Formerly the Stanford Linear Accelerator Center), and the Environmental Molecular Sciences Laboratory (EMSL) at Pacific Northwest National Laboratory all published papers on their latest joint accomplishment. Conceptual drawing of silicon filling carbon shell, TEM photo of actual expansion, and life cycle analysis for yolk-shell batteries Expansion and contraction of anodes and cathodes during charging and discharging of batteries causes flexing and eventual breakdown of a battery’s internal components. Cui and other researchers have tried various strategies to mitigate or eliminate this flexing, but the latest tactic seems to promise longer battery life and greater power and energy. Calling it a “yolk-shell structure,” researchers seal commercially available single silicon nanoparticles in “conformal, thin, self-supporting carbon shells, with rationally-designed void space between the particles and the …