Engineering On The Edge

We’re always happy to hear about any advancements that can improve the performance of rechargeable batteries — particularly if those advancements could make lithium ion batteries robust enough for transportation and renewable energy storage applications.

A group of researchers at Stanford published a paper in March in the journal Nature Nanotechnology describing their work using silicon, as opposed to graphene, as an anode material in lithium ion batteries. While silicon has a larger charge storage capacity, it has inherent properties that make it less stable than graphene, which limits the lifecycle of silicon anodes to hundreds of cycles.

The Stanford group, however, has shown that “anodes consisting of an active silicon nanotube surrounded by an ion-permeable silicon oxide shell can cycle over 6,000 times in half cells while retaining more than 85% of their initial capacity.” Batteries using these silicon anodes had a charge capacity of around eight times that of a conventional carbon anode.

The research was conducted by the SLAC National Accelerator Laboratory, which Stanford operates for the U.S. Department of Energy. The group has been developing this concept for several years, but the recent innovation — using a double-walled silicon nanotube coated with a thin layer of silicon oxide — prevents the outside wall of the nanotube from expanding and damaging the anode.

You can read more about the technology on associate professor Yi Cui’s website.