Conformal layer-by-layer growth of hybrid polymer/inorganic nanolaminates for Li-ion batteries - LaminaLion

Project summary

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 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. The thin-film concept provides the means for good ionic conductance through reduction of the distance for Li-ion diffusion. Combined with the large surface area of a 3D structured surface (e.g. etched pillars or nanowires) an acceptable battery capacity is maintained as the total electrode volume is preserved by the increase in effective surface. Remaining technological issues are (i) the mechanical strain induced in the rigid solid stack during charge/discharge which limits the life time of the battery and (ii) pinholes in the films which limits their minimum thickness and as such the battery power (ionic conductance). The main objective of this project is to develop a mechanically flexible solid electrolyte in the form of a conformal thin-film stack which is to be used for 3D thin-film solid-state lithium-ion batteries. The success of this objective is measured through the durability (cycle life time) of a 3D thin-film micro-battery demonstrator. The second objective is to obtain pinhole-free thin-films constituting a thin-film electrolyte stack with total thickness down to 100nm or less to achieve good ionic conductance. The success of this objective is measured through the performance of the 3D thin-film micro-battery demonstrator. These objectives will be achieved through the application of ALD/MLD processes. Our final goal is a functional battery stack with fast charging/discharging kinetics and long cycle life time.