This invention describes a design and manufacturing process of aligned-porosity, high energy density and low tortuosity electrodes. Such electrodes are manufactured by a directional freeze-casting process that involves a ceramic suspension of solid particles in a liquid, producing unidirectional crystals. The invention also provides means to manipulate the porosity and microstructure of the ceramic structures by changing the processing parameters such as initial slurry concentration. Additionally, additives can be mixed in the ceramic slurry to modify the crystalline structure of ice. After subsequent freeze drying, these changes are replicated in the ceramic structure and lead to improved performance of the final product.