Lithium-ion batteries could store ten times as much energy per kg of batteries if they were constructed with silicon anodes (compared to traditional li-ion batteries). That is a gravimetric energy density of 1,000 watt-hours per kg. This could almost eliminate the range issue that electric vehicles have, but there is one problem:
Lithium-ion battery anodes absorb lithium ions, expanding during that process, and then contract as the lithium ions leave them. Silicon anodes crack and malfunction during this process because they cannot handle repeated expansion and contraction. This is due to the fact that silicon is brittle.
Researchers at the Georgia Institute of Technology and Clemson University say that they have discovered a way to manufacture li-ion batteries with silicon anodes by utilizing a substance sometimes used as a binding agent, gelling agent, and food additive, a substance derived from brown algae. << Ew.
The substance is alginate and it prevents the silicon anode from cracking and enables it to achieve 8 times the energy density of traditional li-ion batteries. This is one of multiple attempts to address this cracking problem. You can see how silicon nanowires helped to extend the life of this type of battery via this Stanford News piece from a few years ago.
The anode of a lithium-ion battery is where the “energy”/lithium ions are stored and, when electric current is being drawn from the battery, the lithium ions travel over to the cathode and generate that electric current while traveling.
Image via Kristoferb