Microscopic Nickel-Zinc Batteries for Use in Autonomous Microsystems

Microscopic nickel-zinc batteries have been built using microfabrication procedures similar to those used in the microelectronics industry. These batteries were designed for use with autonomous microsystems and are of particular interest for applications that involve remote sensing. It is envisioned that the batteries would be part of a hybrid micropower system that would also include a device for scavenging energy from the environment in order to recharge the batteries and provide for a long operational lifetime. The nickel-zinc batteries that have been developed have a typical footprint of 0.02 cm 2 and a capacity of approximately 0.555 mWh/cm 2 . Over 1000 batteries have been fabricated on a single 4 in. wafer. One of the most important characteristics of these batteries is their ability to discharge at high rates (⩾100 mA/cm 2 ), making it possible to extract more than 1 mW (per cell) from these very small cells. Also, initial results show that more than 2000 cycles of a microelectromechanical systems (MEMS) type duty cycle are possible. The high rate performance, small size, and long cycle life of these batteries make them suitable for microsystem applications. In addition, the microfabrication procedure that has been developed should enable the fabrication of these batteries on the same substrate used for other system components. © 2001 The Electrochemical Society. All rights reserved.