Graphene-Based Inks for Flexible Supercapacitor Electrodes: A Review

Abstract

In the world of consumer electronics, flexible and wearable electronic devices have witnessed a remarkable transformation, and flexible supercapacitors (SCs) hold tremendous potential as a power source for these electronic devices. Printing technologies, such as inkjet and screen printing, have emerged as cost-effective and scalable manufacturing techniques for the fabrication of flexible SC electrodes. As a key element of printing technology, ink must have the right balance of conductivity and rheological properties to fabricate high-performance flexible electrodes. Graphene stands out as a promising active pigment for conductive ink due to its remarkable characteristics such as high surface area, excellent electrical conductivity, and mechanical properties. Recently, extensive research has been conducted on the development of graphene-based inks for their effective utilization in SC printing methods. This review summarizes these advances and systematically connects the graphene ink formulation with its rheological properties and correlates finally with the electrochemical performance of inkjet-and screen-printed SC electrodes.

Applicability of the MoS2–aSiC Heterostructure for Durable Supercapacitance and NO2 Gas Sensing in a Harsh Environment

“…The surface-dependent gas-sensing mechanism of the semiconductor materials occurs through the environmental oxygen adsorption on the surface of the sensing element . Depending on the sensor’s temperature, the oxygen molecules reside over it in the form of molecular or atomic species.…”

“…Similarly, Wang et al demonstrated the stable supercapacitor performance of Ni x S y /MoS 2 hybrid nanomaterials with enhanced energy storage capability . Recently, materials such as carbon compounds, − transition-metal dichalcogenides, − ferromagnetic shape memory alloys, − perovskite materials, metal oxides, − nitrides, − carbides, two-dimensional (2D) conjugated metal–organic frameworks (c-MOFs), etc. have been widely used in various electronic devices.…”

Development of Inks with Fillers of NbS3 Quasi-One-Dimensional Charge-Density-Wave Material

“…In printing electronics, the thermophysical properties of the ink and the size of the injecting nozzle are key factors in the formation of proper ink droplets with desirable characteristics. − The droplet formation criteria is determined by the Z -number, Z = ζ ρ a / μ , a dimensionless parameter in which ζ, ρ, and μ are respectively the surface tension, density, and the dynamic viscosity of the ink solution, and a is the diameter of the injecting nozzle. , A Z -number range of 1 ≤ Z ≤ 14 generally results in good droplet formation and its uniform distribution at the intended regions on the substrate . Inks with Z < 1 or Z > 14 result in elongated ligaments or satellite droplet formation which would result in undesirable printing patterns. ,− To tune the properties of our ink, we collected the precipitate part of the liquid-phase exfoliated NbS 3 and transferred it to a secondary solvent of 5 mL of isopropyl alcohol (IPA). The solution underwent a 10 min bath sonication for uniform filler dispersion and to prevent filler agglomeration.…”

Environmentally Friendly Water-Based Reduced Graphene Oxide/Cellulose Nanofiber Ink for Supercapacitor Electrode Applications

“…The water-based rGO/CNF film with optimal CNF content can facilitate efficient electron transport throughout the material and increase hydrophilicity while maintaining the electrical conductivity of the film. This ink can be utilized to produce flexible and scalable electrodes with adjustable morphology and electrochemical performance using a variety of printing methods, including screen, spray, and inkjet printing . As the ink uses water as its main solvent instead of hazardous organic solvents, it is a more environmentally friendly and sustainable option.…”

“…This ink can be utilized to produce flexible and scalable electrodes with adjustable morphology and electrochemical performance using a variety of printing methods, including screen, spray, and inkjet printing. 22 As the ink uses water as its main solvent instead of hazardous organic solvents, it is a more environmentally friendly and sustainable option. Consequently, this novel ink paves the way for the development of high-performance, environmentally friendly, and cost-effective supercapacitors with significant potential to transform energy storage in various applications, such as wearable electronics and health monitoring devices.…”