Conventional batteries use thick electrodes that provide high energy density, but have large ion transport lengths that limit their current densities. Thin film batteries utilize thin layers of material and small transport lengths for higher power, but are limited in their total energy due to low mass loading. Three-dimensional batteries combine both high mass loading and small ion transport lengths due to their architected design, allowing for both high energy and power densities over a small footprint area. Accessing height in battery design permits much more active material than a planar thin film battery. Modern nanofabrication techniques, such as two-photon lithography, can fabricate 3D structures at the micro and nano scale that can be incorporated into a small-scale architected 3D cell. This type of battery could power the next generation of bio-implantable devices and miniaturized wearable sensors.

We demonstrate the fabrication of architected anodes using two-photon lithography to form a polymer scaffold. A gold layer on the nickel current collector alloys with lithium, creating an adhesion layer that assists lithium electrodeposition. The cathode used is iodine mixed with poly(2-vinylpyridine) (P2VP), which forms a lithium iodide solid electrolyte in situ when the anode and cathode come in contact and can be poured into the structure in its molten state. The geometry of the anode is determined by surface area and the pore size is determined to accommodate the thickness of the lithium iodide layer and infiltration of cathode. The increase in surface area and decrease in ion transport lengths from the 3D architecture provide improved performance of the primary battery over planar cells with the same footprint area. Other battery chemistries could be investigated with such a battery design to enhance performance.