Printed Silver Nanowire-PEDOT:PSS Composite Electrodes for Flexible Transparent Microsupercapacitor Applications

Abstract

The integration of microsupercapacitors (mSCs) with flexible/wearable electronic devices can greatly advance the capabilities of these devices. In this work, a robust flexible transparent mSC is constructed using silver nanowires (Ag NWs) combined with a conducting polymer, poly(3,4-ethylenedioxythiophene):polystyrenesulfonate (PEDOT:PSS), which exhibits excellent electrochemical stability and cyclability. Typically, the fabrication of such composite electrodes for supercapacitors (SCs) is a multistep process requiring electro/in situ polymerization, whereas in this work, a simple two-step direct ink writing is adopted. An ink made of Ag NWs and PEDOT:PSS is used to print the electrodes in an interdigitated design. These are then coated by a [poly(vinyl alcohol)]/H 3 PO 4 (orthophosphoric acid) polymer electrolyte to obtain the mSC with a transparency of 84.6% at 550 nm. The optical, electrical, and electrochemical properties of the mSC are optimized by varying the concentration of Ag NWs in PEDOT:PSS. The charge-transfer resistance decreases, and the electrochemically active surface area increases with the concentration of Ag NWs. Compared with pure PEDOT:PSS electrodes, the composite electrodes exhibit significantly lower internal resistance and nearly 2.5 times higher areal capacitance. The mSC also retains its capacitance with increasing current densities, operating in a fixed voltage window of 1.2 V. The device shows excellent electrochemical stability over 10000 charge−discharge cycles along with excellent mechanical flexibility. These results show that a Ag NWs:(PEDOT:PSS)-based mSC can act as a good flexible and transparent energy source for wearable electronic applications.

Comparative Study of Electrochromic Supercapacitor Electrodes Based on PEDOT:PSS/ITO Fabricated via Spray and Electrospray Methods

“…The band at 1431 cm −1 is particularly significant as it reflects the oxidation (doping) level of PEDOT:PSS, which, due to the more porous structure of the electrode coated by the electrospray method, is observed at approximately 1438 cm −1 with a shift of about 7 cm −1 . This shift may also be attributed to a decrease in the ratio of PSS counterion structures within the PEDOT chain depending on the coating method . Furthermore, in the FT-IR spectrum of PEDOT:PSS electrodes, the peaks at 1599 and 1520 cm −1 correspond to the CC stretching in the aromatic rings of PSS and the thiophene ring of PEDOT, respectively.…”

“… 32 This shift may also be attributed to a decrease in the ratio of PSS counterion structures within the PEDOT chain depending on the coating method. 33 Furthermore, in the FT-IR spectrum of PEDOT:PSS electrodes, the peaks at 1599 and 1520 cm −1 correspond to the C=C stretching in the aromatic rings of PSS and the thiophene ring of PEDOT, respectively. The peak at 1412 cm −1 indicates the C−C stretching in the thiophene ring of PEDOT.…”

Fabrication of Flexible Transparent Conductive Films via an Energy-Efficient In Situ Chemical Welding and Reinforcement Strategy

“…Faced with the above situation, researchers have developed secondary strengthening strategies for AgNWs, including the formation of AgNW networks to reduce the contact resistance among nanowires by thermal induction, pulsed laser, mechanical pressurization, and other welding strategies. In addition to these methods, efforts have been directed toward bolstering the adhesion of AgNWs to the substrate by printing transfer, coating polymers, , adding binders, polymerizing in situ, and encapsulating . For example, Youn et al employed silver nanocrystals with the diameters much smaller those of nanowires to weld the joints of AgNWs through local thermal reduction, and the formed stable network structure resulted in a reduction of the average resistance of the film to 16.7 Ω/sq .…”