Solid-state microscale lithium batteries prepared with microfabrication processes

The miniaturization of power sources is important for meeting the requirements of low power, mass and volume for nano- or microelectronics and MEMS devices. In this paper a dexterous microfabrication process was developed for preparing microscale solid-state lithium batteries. The active size of a single microbattery is 500 mu m x 500 mu m and its thickness is 1.5 mu m. LiCoO2 films prepared by RF sputtering, then annealed at moderate temperature (500 degrees C), were employed as a cathode electrode, and LiPON and Al films were used as a solid electrolyte and an anode electrode, respectively. An individual microbattery delivers a capacity of about 17 nAh at a current of 5 nA at the initial cycles, and can be operated at as high as 40 nA discharge current.