Take sodium titanate as a negative, porous activated graphene as a positive pole, what kind of “spark” will occur when they bind? Reporters recently learned from the Dalian Institute of Chemical Physics of the Chinese Academy of Sciences, the Institute Wu Zhongshuai researcher team with Baoxin and academician team, so that “sea urchin” and graphene combined to develop a high energy density, high heat resistance of flexible sodium ion micro-supercapacitor.
Flexible sodium ion micro-supercapacitor schematic strains for units interviewed
Micro sensors, micro-robots, self-powered microsystems, etc. can not be separated from the micro-chemical energy storage device, the device mainly refers to a class of electrode size in the micron range of small power supply, is considered to be flexible, miniaturized, intelligent integrated electronic products, the key power supply, currently mainly divided into micro-cells and micro-supercapacitors, and hybrid micro-supercapacitors that have emerged in recent years.
It is reported that micro-batteries have a high energy density, but their power density is low, and micro-supercapacitors have higher power density, but lower energy density. Hybrid micro-supercapacitors combine the advantages of the high energy density of micro-battery and the high power density of micro-supercapacitors to become a new type of micro-chemical energy storage device, which is more representative of the lithium-ion micro-supercapacitor.
Lithium-ion micro-supercapacitors have high energy and power density, but their large-scale applications are subject to the resource limitations of lithium metal and high development costs (the crustal abundance of lithium is 0.006%). In contrast, sodium is rich in crustal resources, accounting for 2.74 percent, the development cost is relatively low, and lithium electrochemical properties are similar, the development of sodium ion micro super capacitor has important application prospects.
The research and development team of Dalian Chemical Institute of the Chinese Academy of Sciences has successfully constructed a flexible sodium ion microcapacitor for the sodium titanate of sea urchin as a battery-type negative, porous activation of graphene as the positive pole of capacitive type, combined with high-pressure ion liquid gel electrolyte. Through the effective coupling of battery-type negative and capacitive positives, they enable dyed-ion micro-supercapacitors to operate steadily at 3.5 volts, with high energy density of 37.1 milliwatt hours per cubic centimeter, and an ultra-low self-discharge rate.
According to the researchers, the sodium-ion micro-supercapacitor has a multi-directional fast ion diffusion channel, greatly reducing the charge transfer resistance and significantly increasing the power density. At the same time, due to the flat geometry of the device and the non-combustibility of the ion gel electrolyte, the micro-device has good mechanical flexibility and high temperature stability of 80 degrees C.