Flexible Transparent Bifunctional Capacitive Sensors with Superior Areal Capacitance and Sensing Capability based on PEDOT:PSS/MXene/Ag Grid Hybrid Electrodes

Abstract

Flexible transparent supercapacitors (FTSs) have aroused considerable attention. Nonetheless, balancing energy storage capability and transparency remains challenging. Herein, a new type of FTSs with both excellent energy storage and superior transparency is developed based on PEDOT:PSS/MXene/Ag grid ternary hybrid electrodes. The hybrid electrodes can synergistically utilize the high optoelectronic properties of Ag grids, the excellent capacitive performance of MXenes, and the superior chemical stability of PEDOT:PSS, thus, simultaneously demonstrating excellent optoelectronic properties (T: ≈89%, Rs: ≈39 Ω sq−1), high areal specific capacitance, superior mechanical softness, and excellent anti‐oxidation capability. Due to the excellent comprehensive performances of the hybrid electrodes, the resulting FTSs exhibit both high optical transparency (≈71% and ≈60%) and large areal specific capacitance (≈3.7 and ≈12 mF cm−2) besides superior energy storage capacity (P: 200.93, E: 0.24 µWh cm−2). Notably, the FTSs show not only excellent energy storage but also exceptional sensing capability, viable for human activity recognition. This is the first time to achieve FTSs that combine high transparency, excellent energy storage and good sensing all‐in‐one, which make them stand out from conventional flexible supercapacitors and promising for next‐generation smart flexible energy storage devices.

Recent progress in energy, environment, and electronic applications of MXene nanomaterials

“…To achieve this, Cheng et al carried out a surface treatment with octadecyl trichlorosilane which decreased the wettability and surface energy of Ag lines. 94 With the help of this technique, Cheng et al improved the optoelectronic properties of a PEDOT:PSS/MXene/Ag electrode. 94 The transmittance spectra of these electrodes are shown in Fig.…”

“…94 With the help of this technique, Cheng et al improved the optoelectronic properties of a PEDOT:PSS/MXene/Ag electrode. 94 The transmittance spectra of these electrodes are shown in Fig. 6d and e before and after the treatment with octadecyl trichlorosilane.…”

Recent Advances of Capacitive Sensors: Materials, Microstructure Designs, Applications, and Opportunities

“…Wearable, flexible, and stretchable sensors based on piezoresistive, triboelectric, piezoelectric, and capacitive mechanisms have experienced rapid advancement to meet sensing demands in a diverse range of applications (e.g., soft prosthetic hand for amputees [1][2][3][4] and flexible, human activity recognition and body signal monitoring, [5,6] artificial intelligence, [7,8] and large area skin-interfaced sensing [9] ). Piezoelectric and triboelectric sensors have the merits of self-power property and fast response time.…”

The Fabrication, Properties, and Application of a Printed Green Ag NWs-Based Flexible Electrode and Circuit

“…Flexible printable electronics are being developed for small, thin, and light significant applications such as film sensors, flexible transparent conductive films (FTCF), solar panels, flexible transparent supercapacitors, transparent conducting electrodes, and especially the triboelectric nanogenerator (TENG). Traditionally, electrode contact with the external circuit is an important part to realize these devices’ function.…”