Conformal Deposition For 3D Thin-Film Batteries

For the application of durable micro-storage for autonomous systems and implants, 3D thin-film batteries are leading candidates. Lithium ion batteries have the highest energy density of all known systems and are thus the best choice also for these rechargeable micro-batteries. Since liquid electrolyte based batteries present safety issues and limitations in size and design, pure solid state devices are considered particularly for miniaturization. Planar thin-film lithium and lithium ion batteries are at present commercially available but have limited capacity (<1mAh/cm(2)). The capacity can be increased by coating the thin-film stacks on micro-or nanostructured surfaces (3D thin-film batteries). The main advantage of thin-film (TF) batteries is that its power can be increased by scaling down the film thickness. The main technological challenges in the introduction 3D TF batteries are pinhole-free and chemically uniform conformal coating of the cathode, electrolyte and anode thin-film stack.