Carbon Nanotube/Reduced Graphene Oxide/Aramid Nanofiber Structural Supercapacitors

Abstract

Reduced graphene oxide/aramid nanofiber (rGO/ANF) supercapacitor electrodes have a good combination of energy storage and mechanical properties, but ion transport remains an issue toward achieving higher energy densities at high current because of the tightly packed electrode structure. Herein, carbon nanotubes (CNTs) are introduced to prevent rGO flake stacking to improve the rate capability of the rGO/ANF structural supercapacitor. The effect of CNTs on the rGO/ANF composite electrode’s mechanical and electrochemical properties is investigated by varying the composition. The addition of 20 wt % CNTs led to an increase in Young’s modulus up to 10.3 ± 1.8 GPa, while a maximum in ultimate strain and strength of 1.3 ± 0.14% and 55 ± 6.8 MPa, respectively, was found at a loading of 2.5 wt % CNTs. At low specific currents, the electrodes performed similarly (160–170 F g–1), but at high specific currents (5 A g–1), the addition of 20 wt % CNTs led to a significantly higher capacitance (76 F g–1) as compared to that of rGO/ANF electrodes without CNTs (26 F g–1). In addition, the energy density also improved significantly at high power from 1.4 to 5.1 W h L–1 with the addition of CNTs. The improvement in mechanical properties is attributed to the introduction of additional hydrogen-bonding and π–π interactions from the carboxylic acid-functionalized CNTs. The increase in capacitance at higher discharge rates is due to improved ion transport from the CNTs. Finally, in situ electrochemomechanical testing examines how capacitance varies with strain in these structural electrodes for the first time.

Mechanically Improved Zn-Ion Battery Cathodes Based on Branched Aramid Nanofibers

“…This composition was selected because it exhibited the best mechanical properties. For this experiment, a custom-built instrument was used that consisted of a tensile stage and a 3D-printed electrochemical cell described in refs and . A half-cell was fabricated in the 3D-printed cell, as shown in Figure a.…”

“…Simultaneous electrochemical and mechanical testing was performed using an in-lab-built coupling instrument, as shown in our previous work. 22 A 3D-printed electrochemical cell was filled with 10 mL of 2 M ZnSO 4 + 0.2 M MnSO 4 aqueous electrolyte until a meniscus was created. The tabbed ends of the composite electrode strips were mounted on the grips of a tensile tester, while the gauge length of the specimen was in contact with the meniscus of the electrolyte.…”

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.…”

Composite Structural Supercapacitors: High-Performance Carbon Nanotube Supercapacitors through Ionic Liquid Localisation

“…While this combination of CNTs and PVDF ionogels have been explored for the fabrication of SSCs previously, few electrolyte configurations have been explored for optimisation of both electrochemical and mechanical performance in composites aside from [ 12 ]. Previous SSC configurations have examined sandwiching a self-contained supercapacitor stack with ionogel electrolyte into a composite [ 12 , 47 ] or infusing the whole SSC and composite structure with an electrolyte/resin mixture as the matrix material [ 5 , 11 , 23 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 ]. Embedding a self-contained supercapacitor is structurally disruptive and produces localised increases in laminate thickness and stress concentrations.…”