In-plane flexible solid-state microsupercapacitors for on-chip electronics
By Zhang, Xingyan; Zhao, Wen; Wei, Lu; Jin, Yiyi; Hou, Jie; Wang, Xiaoxue; Guo, Xin
Published in Energy 2019
Small-scale supercapacitors or microsupercapacitors (MSCs) can be integrated with miniaturized electronics to work as stand-alone power sources, or as efficient energy storage units coupling with energy harvesters to realize self-powered microdevices. Despite many advances, research and development of MSCs are still in their infancy. In this work, in-plane flexible solid-state MSCs based on interdigital electrodes are developed through a facile, cost-effective, universal and industrially applicable protocol, i.e. screen printing technique. To verify the generality of such method, activated carbon (AC) nanospheres and molybdenum oxide (MoO3-x) nanorods as representative electrical double-layer capacitive material and intercalation pseudocapacitive material are used as the electrode active material, respectively. Using a highly viscous AC nanosphere or MoO3-x nanorod paste, shape-designable microelectrodes with an effective area of 0.415 cm2, and a spacing of 250 ?m between the two electrode fingers are printed on flexible substrate in several seconds. The MSCs can deliver high areal capacitances and energy densities (5.04 mF cm?2 and 0.7 ?Wh cm?2 for the MSC with AC nanosphere electrodes, 41.7 mF cm?2 and 5.8 ?Wh cm?2 for the MSC with MoO3-x nanorod electrodes), own excellent rate capability and long cycle life for both the electric double-layer capacitive material and pseudocapacitive material. This work demonstrates the opportunity and practicability for developing MSCs for flexible on-chip electronic devices.