High-Performance Microsupercapacitors Based on Two-Dimensional Graphene/Manganese Dioxide/Silver Nanowire Ternary Hybrid Film

Abstract

Microsupercapacitors (MSCs), as one type of significant power source or energy storage unit in microelectronic devices, have attracted more and more attention. However, how to reasonably design electrode structures and exploit the active materials to endow the MSCs with excellent performances in a limited surface area still remains a challenge. Here, a reduced graphene oxide (RGO)/manganese dioxide (MnO2)/silver nanowire (AgNW) ternary hybrid film (RGMA ternary hybrid film) is successfully fabricated by a facile vacuum filtration and subsequent thermal reduction, and is used directly as a binder-free electrode for MSCs. Additionally, a flexible, transparent, all-solid state RMGA-MSC is also built, and its electrochemical performance in an ionic liquid gel electrolyte are investigated in depth. Notably, the RGMA-MSCs display superior electrochemical properties, including exceptionally high rate capability (up to 50000 mV·s(-1)), high frequency response (very short corresponding time constant τ0 = 0.14 ms), and excellent cycle stability (90.3% of the initial capacitance after 6000 cycles in ionic liquid gel electrolyte). Importantly, the electrochemical performance of RGMA-MSCs shows a strong dependence on the geometric parameters including the interspace between adjacent fingers and the width of the finger of MSCs. These encouraging results may not only provide important references for the design and fabrication of high-performance MSCs, but also make the RGMA ternary hybrid film promising for the next generation film lithium ion batteries and other energy storage devices.

Improved conductivity and capacitance of interdigital carbon microelectrodes through integration with carbon nanotubes for micro-supercapacitors

“…Recent demand of thin and light micro-supercapacitors for portable electronic devices has made supercapacitors a popular type of power source and energy storage unit [7][8][9][10][11][12][13][14]. Carbonaceous materials, such as activated carbon, carbon nanotubes (CNTs) and graphene, are important and essential electrode materials for use in micro-supercapacitors [2].…”

On‐Chip Micro‐Pseudocapacitors for Ultrahigh Energy and Power Delivery

“…This is probably due to a higher salt concentration in the electrolyte as the result of gel drying. A stack capacitance up to 99.1 F cm −3 , corresponding to an energy density of 6.74 mW h cm −3 , has been obtained from the solid‐state hierarchical NPG/MnO 2 MPCs with a MnO 2 plating time of 11 min (Figure 4b), which is much higher than the literature values of the best carbon/graphene‐based MSCs (1.3 F cm −3 for onion‐like carbon based MSCs,2 3.1 F cm −3 for laser‐written reduced graphene oxide MSCs,8 3.05 F cm −3 for laser‐scribed graphene MSCs,9 17.9 F cm −3 for reduced graphene MSCs10 and 6.1 F cm −3 for reduced graphene oxide/carbon nanotube MSCs12) and pseudocapacitive microdevices (16.4–39.3 F cm −3 for MnO x /Au multilayer MSCs,19 26.5–66.0 F cm −3 for polyaniline nanowire array MSCs,17 8–25 F cm −3 for CoO/carbon nanotube MSCs,39 4.42 F cm −3 for graphene/MnO 2 /Ag nanowire MSCs40 and 30–50 F cm −3 for MWCNT/MnO x MSCs41) (Table S2, Supporting Information). Even at a high current density of 0.5 mA cm −2 (0.5 mA cm −2 corresponds to about 18.4 A g −1 MnO2 for 7 min plating, and 13.2 A g −1 MnO2 for 11 min plating), the stack capacitance is as high as 61.5 F cm −3 (Figure 4b).…”

Deformable and Transparent Ionic and Electronic Conductors for Soft Energy Devices

“…As a result, the use of Ag NWs as STECs for supercapacitors has been constrained and they have only been used as supporters or auxiliary conductors. [190][191][192][193][194] Recently, Lee et al reported that the stability of Ag NWs can be enhanced by conformal coating of the Au thin layer as shown in Figure 11b. [85] The Ag-Au NW electrode presented enhanced air/electrochemical stability (Figure 11c), and the resistance increased 2.6 times at 30% strain.…”