All-Solid-State Lithium-Ion Microbatteries: A Review of Various Three-Dimensional Concepts

With the increasing importance of wireless microelectronic devices the need for on‐board power supplies is evidently also increasing. Possible candidates for microenergy storage devices are planar all‐solid‐state Li‐ion microbatteries, which are currently under development by several start‐up companies. However, to increase the energy density of these microbatteries further and to ensure a high power delivery, three‐dimensional (3D) designs are essential. Therefore, several concepts have been proposed for the design of 3D microbatteries and these are reviewed. In addition, an overview is given of the various electrode and electrolyte materials that are suitable for 3D all‐solid‐state microbatteries. Furthermore, methods are presented to produce films of these materials on a nano‐ and microscale. Three‐dimensional (3D) solid‐state microbatteries are promising for efficient and high energy density storage to power future generations of microelectronic devices. An overview of several 3D microbattery concepts proposed by various research groups is given. Several suitable electrode and electrolyte materials for these batteries are reviewed together with some key deposition methods to produce thin films of these materials.