Interfacial Engineering of Reduced Graphene Oxide for Aramid Nanofiber‐Enabled Structural Supercapacitors

Abstract

Structural energy storage systems can simultaneously store energy and bear mechanical loads and are emerging technologies for electric vehicles, aircrafts, and satellites since they offer significant mass and volume savings. However, many of the materials used in energy storage applications are not mechanically robust or, on the other hand, mechanically stiff materials are not necessarily electrochemically active. One solution is to combine reduced graphene oxide (rGO) sheets and aramid nanofibers (ANFs). Here we hypothesize that engineering the interfacial interactions between rGO sheets and the ANFs will lead to enhanced mechanical properties, as noncovalent interactions offer multiple sites for load transfer. rGO sheets are functionalized with carboxylic acid (−COOH) and amine (−NH2) groups, and the effect on the mechanical and electrochemical performance of nanocomposite supercapacitor electrodes is investigated. Notably, the −NH2 functionalization and the addition of ANFs leads to a dramatic 200 % improvement of the strength of the electrodes without significantly compromising the electrochemical performance. Furthermore, it is demonstrated that these electrodes’ multifunctionality is superior to other state‐of‐the‐art structural electrodes and may pose possible replacements for steel or epoxy. These findings provide critical knowledge for the design of next‐generation multifunctional electrodes in that we highlight the importance of interfacial engineering.

Highly Multifunctional Dopamine-Functionalized Reduced Graphene Oxide Supercapacitors

“…Moreover, these electrodes exhibited a specific capacitance of $105 F/g. 50 In this work, we obtained higher specific capacitance (23%) while maintaining similar mechanical properties and while using only 10 wt % BANFs and dopamine functionalization. Figure 6C illustrates the specific Young's modulus (GPa$cm 3 /g) versus specific energy (W$h/kg), where the dashed lines represent the multifunctional efficiency.…”

“…Up to now, the best rGO/aramid nanofiber-containing structural electrodes were the rGO-NH 2 /25 wt % ANFs, in which rGO sheets had been modified with amine functional groups. 50 These electrodes exhibited Young's modulus of $12 GPa and ultimate tensile strength of $100 MPa. In that report, the increased mechanical performance was attributed to the enhanced hydrogen-bonding interactions between the ANF amide bonds and the rGO amine groups caused by the amine functionalization.…”

“…39 ANFs have been used in a variety of applications including energy storage. 22,[40][41][42][43][44][45][46][47][48][49][50][51] ANF/PEDOT:poly(styrene sulfonate) electrodes exhibited specific capacitance of 112 F/g, Young's modulus of 5 GPa, and tensile strength of 76 MPa. 48 Last year, branched aramid nanofibers (BANFs) were first reported and were shown to bear further improved mechanical properties over ANFs.…”

Designing Structural Electrochemical Energy Storage Systems: A Perspective on the Role of Device Chemistry

“…CFs may be electrochemically active themselves, or act as framework and current collector for a multifunctional matrix packed around them. EDLCs are particularly attractive, since the energy storage process is entirely physical, depending only on the interface between electrode and electrolyte ( Figures 2A,B ) ( Li et al, 2010 ; Qian et al, 2013a ; Shirshova et al, 2013a ; Qian et al, 2013b ; Javaid et al, 2014 ; Shirshova et al, 2014 ; Westover et al, 2014 ; Greenhalgh et al, 2015 ; Javaid et al, 2016 ; Senokos et al, 2016 ; Kwon et al, 2017 ; Senokos et al, 2017 ; Shen and Zhou, 2017 ; Xu and Zhang, 2017 ; Li et al, 2018a ; Chen et al, 2018 ; Javaid et al, 2018 ; Javaid and Irfan, 2018 ; Muralidharan et al, 2018 ; Senokos et al, 2018 ; Aderyani et al, 2019 ; Flouda et al, 2019a ; Chen et al, 2019 ; Patel et al, 2019 ; Reece et al, 2019 ; Patel et al, 2020b ; Rana et al, 2020 ; Reece et al, 2020 ; Sun et al, 2020 ; Sánchez-Romate et al, 2021 ; Subhani et al, 2021 ; Xu et al, 2021 ). The central advantage for SESDs, is that there is little or no change in volume, and no (re)dissolution of material, associated with the electrochemical process, minimizing stresses, and simplifying the structural design, whilst ensuring an excellent cycle life.…”

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

“…Early studies in this area primarily focused on supercapacitors with a simple two symmetric electrode design, and inspiration built from work on polymer and/or solid battery architectures. [14][15][16][17][18][19][20][21] Challenges among these early studies included a lack of clear justication for multifunctional operation and/or performance, and extremely low areal and gravimetric energy storage capability in the order of a few to tens of mF cm À1 . 2 While many of these challenges remain, efforts to benchmark multifunctional performance are starting to emerge.…”