Lightweight Kevlar‐Reinforced Graphene Oxide Architectures with High Strength for Energy Storage

Abstract

A multifunctional supercapacitor based on reduced graphene oxide (rGO) hydrogels deposited onto Kevlar fibers and woven cloth is reported, which exhibits both excellent mechanical performance and electrochemical energy storage. The specific strength of rGO hydrogel–Kevlar fibers reaches 1.6 MPa m3 kg−1 and the specific capacitance is 57 F g−1 with 38.1% of rGO. Such high specific strength is comparable to one of the as‐received Kevlar fibers (2.0 MPa m3 kg−1), indicating that the gelation process does not harm the fibers. The gel‐state symmetric device based on rGO hydrogel–Kevlar cloth survives impact from a 9.1 N force from a falling metal ball as well as deformation during bending to 90°. The high specific strength is due to the Kevlar while the specific capacitance stems from the 3D interconnected macrostructure of rGO hydrogels. To demonstrate the combination of these properties, a multifunctional efficiency is introduced based on the geometric average of mechanical and energy storage properties as compared to epoxy and carbon aerogel supercapacitor, respectively. This metric predicts an optimum combination or properties at a volume ratio of Kevlar/rGO gel between 0.0008 and 0.35.

In Situ Loading of Polypyrrole onto Aramid Nanofiber and Carbon Nanotube Aerogel Fibers as Physiology and Motion Sensors

“…In the present paper, a blend solution of ANFs and CNTs was sent to the water bath through a flow field, and the ANFs were protonated to obtain ANF/CNT hydrogel fibers. The PPy conductive layer was polymerized in situ on the surface and inside the gel, 32 preparing ANF-based aerogel fiber materials 33 with a double conductive network. Internal CNTs can enhance the ANF supporting structure while playing a certain conductive role.…”

Carbon Nanotube/Reduced Graphene Oxide/Aramid Nanofiber Structural Supercapacitors

“…For a multifunctional application, a trade-off in electrochemical and mechanical performances is expected; thus, it is important to identify some optimal combination of the two desired properties. Accordingly, the Ashby plot in Figure compares the energy density and ultimate strength of the electrodes in this work (red stars) with other structural electrodes in the literature. − ,− When compared to other supercapacitors, the rGO/ANF/CNT electrodes performed well with both a good energy density and strength. When compared to similar materials from our group (purple, blue, and orange squares), this work showed a slight improvement in energy density at a small cost in strength.…”

Polymer reinforced carbon fiber interfaces for high energy density structural lithium-ion batteries

“…Our ndings of this work indicate that the active battery materials are more effectively utilized in the PAN-coated composite versus the non-PAN coated one. Therefore, to quantitatively evaluate and compare the multifunctional advantage in this structural battery with PAN coatings, we adopted the formalism introduced by Sun et al 22 to evaluate the multifunctional advantage of structural rGOpolymer supercapacitors. Detailed calculations for the multifunctional advantage are presented in Fig.…”

“…2 While many of these challenges remain, efforts to benchmark multifunctional performance are starting to emerge. Sun et al 22 highlight a comparison of improved rGO/Kevlar supercapacitors compared to carbon aerogel/epoxy materials and introduce a formalism to evaluate the multifunctional advantage in structural energy storage. While transitioning from supercapacitors to batteries opens the door to many orders of magnitude greater energy storage in a structural material, this path also brings more advanced challenges due to the electrode volume change associated with charging and discharging.…”