| dc.description.abstract | With the scientific and technological advancements, the society which we live is facing the energy and environmental related problems such as pollution, deficiency of fossil fuels, and global warming. In order to resolve these issues, green-energy and renewable materials as well as their devices are demanded. Supercapacitors (SCs) exhibit high specific capacitance and power density, fast charge-discharge rate, and long cycle life. In addition, they are safe in operation and environmental friendly. Recently, micro-supercapacitors (MSCs) have attracted much interests since they can be further integrated into MEMS and CMOS.
In this work, we introduce planar interdigitated electrode structure based on MoOx thin film electrode materials, which can be further fabricated to on-chip and all-solid-state MSC. This study investigated the influence of the geometric configuration of planar interdigitated MSCs with different interdigitated patterns (varying the interspace, width, length and number of interdigitated fingers) on their electrochemical properties. Furthermore, we introduce a new concept to fabricate MSC based on MoOx/Ag multilayers, with which the volumetric capacitance is much higher than that of the bare MoOx-based MSC. MoOx/Ag multilayer MSC also demonstrates higher energy density and power density. Electrochemical impedance spectroscopy (EIS) confirmed that the electrical conductivity of MoOx was significantly improved due to the incorporation of silver. The corresponding volumetric capacitance increases as the the silver thickness increases. But with the excess silver, the capacitance retention rate was found to be degraded. MoOx/Ag multilayers MSC with a thickness of 1.5 nm for each Ag layer exhibits most excellent cycle stability and highest volumetric capacitance after a large cycling number of 10000 times.
This work indicates that high electronic conductivity of the electrode material is crucial to achieving high specific capacity as well as power and energy density for pseudocapacitors. These excellent electrochemical performance of results suggest that our method and design show great promise for applications in integrated energy storage for all solid-state microsystems technologies. | en_US |