A new “yolk-and-shell” nanoparticle could boost the capacity and power of lithium-ion batteries. MIT’s press release gives a graphic overview of what damages electrodes and shortens battery life. “One big problem faced by electrodes in rechargeable batteries, as they go through repeated cycles of charging and discharging, is that they must expand and shrink during each cycle — sometimes doubling in volume, and then shrinking back. This can lead to repeated shedding and reformation of its “skin” layer that consumes lithium irreversibly, degrading the battery’s performance over time.” Dr. Yi Cui and teams at 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 a similar joint accomplishment three years ago, as reported in this blog. Dr. Cui had studied several alternative ways to reduce the effects of expansion and contraction on electrodes. According to an MIT news release, “Now a team of researchers at MIT, led …
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 …