Abstract: New wireless devices need better batteries, more powerful but still low cost. We have created one—a high-performance lithium-based battery using metal foam (or some other three-dimensional, fillable, conductive material) to make its electrodes. Our battery offers as much as 30% to 100% greater power and energy density. Similar increases in power and energy density typically increase costs tens or hundreds of times. Our increased performance adds no extra cost. Metal foam increases conductivity within the electrode. So electrodes can be made much thicker, but no more resistant. Thicker electrodes bring more power and more energy for the same volume and weight. Our high-performance, low-cost batteries can be used for small wireless devices like smart cards, for larger mobile devices like cell-phones, and even the high-power, high-energy batteries needed for cars. At all sizes, we provide more power and energy at the same cost.