The success of Plug-in hybrids hinge on the development of lithium-ion batteries. Some interesting inventions that will make your cell phone battery ready to drive your car. Differences in chemistry and structure will depend on application.

The most promising electrode chemical makeups, then, involve nano-engineered materials like phosphates of iron, lithium-titanate spinel and, most recently, bundles of silicon nanowires. Making an electrode out of these tiny particles increases the available surface area for the ions to bond to and exchange electrons, avoiding a bottleneck that used to result in deformation (and diminished effectiveness) of traditional materials like graphite.