Tailoring the Porosity and Microstructure of Printed Graphene Electrodes via Polymer Phase Inversion

Abstract

Phase inversion is demonstrated as an effective method for engineering the microstructure of graphene films by exploiting the well-defined solubility characteristics of polymer dispersants. Drying of a tailored phase inversion ink containing a nonvolatile nonsolvent leads to gelation and subsequent pore formation, providing a promising strategy to tailor the porosity of the resulting graphene films. Graphene films with tunable porosity and electrical conductivity ranging from ∼1000 to ∼22 000 S/m are fabricated by this method. Moreover, this dry phase inversion technique is compatible with conventional coating and printing methods, allowing direct ink writing of porous graphene microsupercapacitor electrodes for energy storage applications. Overall, this method provides a straightforward and versatile strategy for engineering the microstructure of solution-processed nanomaterials.

Enhanced electrochemical biosensor and supercapacitor with 3D porous architectured graphene via salt impregnated inkjet maskless lithography

“…A dry gel electrolyte was used for the supercapacitor consisting of poly(vinyl alcohol) and phosphoric acid (PVA/H 3 PO 4 ). 29 In Short, 6 mL of DI water was mixed with 3 mL isopropol alcohol (IPA) and 1 mL concentrated H 3 PO 4 . The solution was then placed on a hotplate (80 1C) and 1 g PVA (poly(vinyl alcohol)) was slowly added until completely dissolved.…”

“…28 Hersam and coworkers used polymer-phase inversion to tailor the porosity of graphene, similarly, the increase in porosity lead to a decrease in conductivity (B1000 S m À1 at 15% glycerol). 29 Alternatively, we have demonstrated that secondary post-processing methods such as laser annealing can significantly increase the conductivity (B100 O sq À1 ) 10 while simultaneously enhancing the electroactive surface area of graphene by nano/micro structuring pores into the graphene by orientating superficial graphene flakes vertically. 10,30,31 However, these methods do not make macrosized pores in the graphene surface or micropores in the graphene lattice structure while retaining electrical conductivity.…”

On the relationship between morphology and conductivity in nanosheet networks

“…In general, nanosheet networks consist of disordered arrays of nanosheets which often have a partial degree of in-plane alignment [26]. Such networks are always quite disordered and display a wide range [41] of morphologies from highly porous [16] to closely packed [38,42]. The morphology tends to vary with deposition method, the specific conditions during deposition and the properties of the nanosheets being deposited.…”

Real‐Time Optical Process Monitoring for Structure and Property Control of Aerosol Jet Printed Functional Materials

“…This insight based on the process metric therefore allows improved print optimization based on film conductivity, which is related to microstructure, rather than conductance alone, which could be relevant for applications in which porosity and surface area are important. [24,25] The quality of the process metric as a predictor for functional properties provides an opportunity for process control.…”