3d Porous High Areal Capacity Lithium-Ion Micro-Batteries
The reduction in size and the improvement in the capability of microsystems are presently limited by the size and the capacity of their on-board power supplies. A key performance metrics for the power supplies of microsystems is the capacity per footprint area, or areal capacity, in mAh/cm2, while the commercial 2D thin film micro-batteries possess low areal capacity of less than 0.2 mAh/cm2. Thus, it’s necessary to load battery components onto scalable 3D architectures to enable electrodes with high areal capacity. In this work, novel fabrication techniques are proposed. A facile high current hydrogen-templated electroplating technique is utilized to generate 3D porous microstructures, which serve as the scaffolds, current collectors, or even active materials for battery electrodes. In addition, electrochemical techniques and laser-machined substrate ensure uniform coating and high utilization of battery active materials to allow superior electrochemical performance. On the half-cell level, Si/NiSn composite anode deliver ultrahigh areal capacity over 40 mAh/cm2; and carbonate-compatible S cathode is developed and possess 4mAh/cm2 areal capacity with 85% capacity retention after 50 cycles at a high current density of 2.5 mA/cm2. On the full cell level, the micro-battery delivers an areal capacity of 3 mAh/cm2 with 2.3 mW/cm2 power density that meets the demands of many micro-electronic device. In addition, a proof-of-concept monolithic full cell based on polymer electrodeposition techniques is demonstrated to accelerate the cell manufacturing process. In conclusion, in this study, microelectronics-compatible fabrication of scalable, high surface area, and porous 3D metal network-based Li-ion micro-batteries is devised to enable electrodes with high areal capacity, high power density, manufacturability, low cost, and good safety performance.