Silicon is mixed with various forms of carbon, including carbon fibers and graphite, which can provide a pathway for electrons to travel through the material, bridging the gaps created by silicon cracks. The battery pack costs more than $10,000, and that's the biggest reason that makes an electric car more expensive than a regular gas-powered car. Envia could solve some key problems and cut the cost of electric vehicle batteries in half. Source: MIT Tech Startups Envia, a startup with funding from General