It will be appreciated that, in some embodiments, the energy storage devices described herein may comprise extremely small devices, as the electrodes and electrolyte may comprise layers having thicknesses as small as about 1 nm. For example, total thicknesses of a unit cell may be as small as about 3 nm, for example, or as large as about 1 μm. Some unit cell embodiments may comprise larger thicknesses, however, and multi-cell devices may take on any suitable thickness, as the number of unit cells is virtually without limit. These small unit cell dimensions may provide for a number of the advantageous properties of the devices. For example, in embodiments, the devices may exhibit extremely large electrical energy densities when charged, such as greater than or about 10 J/cm3, greater than or about 50 J/cm3, greater than or about 200 J/cm3, greater than or about 500 J/cm3, greater than or about 1000 J/cm3, greater than or about 5000 J/cm3, greater than or about 10000 J/cm3, greater than or about 50000 J/cm3, or selected from 10 J/cm3 to 50000 J/cm3. Although the amount of energy stored by a single cell may be small, the dimensionality of the cells may allow many hundreds or thousands or more cells to be included within a small volume, magnifying the overall energy storage capacity greatly.