As a new type of energy storage device, supercapacitors have the advantages of high power density, rapid charge and discharge, long cycle life, and better safety performance. They are widely used in many fields such as consumer electronics, electric vehicle start and stop, and industrial energy management systems. . In recent years, micro, flexible, and intelligent electronic devices have flourished. This requires the construction of new supercapacitors (including miniature, flexible capacitors, smart capacitors, etc.) that match them to meet their energy storage needs.
Laboratory of Clean Energy Chemistry and Materials, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences The group of researchers Yu Xingbin has devoted many years to the research of supercapacitor materials and devices. Recently, they constructed a series of high-performance novel supercapacitors, including asymmetric miniature capacitors and high-temperature flexible capacitors, and explored the charge storage mechanism of metal oxide electrodes in specific ionic liquids; using shape memory alloys as current collectors, Band smart super capacitor.
In this research group, an asymmetric all-solid micro-supercapacitor with graphene quantum dots as the anode and MnO2 as the cathode was fabricated on the interdigitated gold electrode by electrochemical deposition. The device was comparatively studied in several common ionic liquid gel electrolytes. The electrochemical performance, and by optimizing the solid electrolyte composition, achieved a high scan rate (2000 V/s) and a small relaxation time constant (τ0 = 206.9 ms). Related work was published on ACS Applied Materials & Interfaces (2015, 7, 25378−25389).
The researchers used conductive carbon cloth as a current collector, used γ-FeOOH to have an excellent tantalum capacitor behavior in specific ionic liquids, and the ionic liquid gel electrolyte itself had good thermal stability, non-flammability, chemical inertness, and a wide voltage window. Porous carbon//γ-FeOOH asymmetrical all-solid-state flexible supercapacitors. The results of high temperature electrochemical tests show that when the ambient temperature rises to 200oC, the volume energy density of the flexible device can reach 1.44mWh/cm3; the 180oC bending test shows that the device has stable electrochemical energy storage properties. On Materials Chemistry A (2016, 4, 8316–8327).
Smart watches and wristbands have attracted wide attention from consumers because they integrate many different functions into one product. However, the current design of energy storage devices severely limits the power supply capacity and future development space. By proposing a strategy of integrating the strap with the energy storage device, the research group designed and manufactured a strap-type smart flexible super capacitor. A graphene-coated titanium-nickel alloy sheet was used as the negative electrode, and a self-supporting MnO2/Ni sheet prepared by two-step electrochemical deposition was used as the positive electrode. Water and ionic liquid gel electrolytes were used as electrolyte separators respectively, and a solid state flexible supercapacitor was assembled. . Both static and dynamic bending tests demonstrate the excellent mechanical and electrochemical stability of the device. Due to the use of titanium-nickel alloy as the current collector, the device also exhibits shape memory capability. To demonstrate potential applications, the researchers also assembled strap-like super-electric devices and electronic watches. Interestingly, this smart strap not only provides energy to the watch, but also retains shape memory characteristics that can be automatically “worn” on the wrist when in contact with the human body. In addition, even if the strap is in direct contact with the skin, its excellent biocompatibility will not harm the body. Related work was published on Advanced Energy Materials (DOI: 10.1002/aenm.201600763).
The above work has been funded and supported by the National Natural Science Foundation of China and Lanzhou Institute of Chemical Industry for the "1-3" key cultivation project.
