Layer-by-Layer Assembly of Reduced Graphene Oxide and MXene Nanosheets for Wire-Shaped Flexible Supercapacitors

Abstract

As the demand for wearable electronic devices increases, interest in small, light, and deformable energy storage devices follows suit. Among these devices, wire-shaped supercapacitors (WSCs) are considered key components of wearable technology due to their geometric similarity to woven fiber. One potential method for creating WSC devices is the layer-by-layer (LbL) assembly technique, which is a "bottom-up" method for electrode fabrication. WSCs require conformal and adhesive coatings of the functional material to the wire-shaped substrate, which is difficult to obtain with other processing techniques such as vacuum filtration or spray-coating. However, the LbL assembly technique produces conformal and robust coatings that can be deposited onto a variety of substrates and shapes, including wires. In this study, we report WSCs made using the LbL assembly of alternating layers of positively charged reduced graphene oxide functionalized with poly-(diallyldimethylammonium chloride) and negatively charged Ti 3 C 2 T x MXene nanosheets conformally deposited on activated carbon yarns. In this construct, the added LbL film enhances capacitance, energy density, and power density by 240, 227, and 109%, respectively, relative to the uncoated activated carbon yarn, yielding high specific and volumetric capacitances (237 F g −1 , 2193 F cm −3 ). In addition, the WSC possesses good mechanical stability, retaining 90% of its initial capacity after 200 bending cycles. This study demonstrates that LbL coatings on carbon yarns are promising as linear energy storage devices for fibrous electronics.

Ti3C2TX MXene Modified with ZnTCPP with Bacteria Capturing Capability and Enhanced Visible Light Photocatalytic Antibacterial Activity

“…As shown by the high-resolution C 1s spectra in Figure 2c, CTi, CC, and CO bonds exist in Ti 3 C 2 T X , whereas CC, CNC, CO, and CO bonds are observed from both ZnTCPP and ZnTCPP/Ti 3 C 2 T X . [25] The O 1s results are similar to those of C 1s. As shown in Figure 2d, the peaks of Ti 3 C 2 T X at 532.22, 530.39, and 528.48 eV are associated with TiO, CO, and CTiOH, respectively.…”

MXene‐Copper/Cobalt Hybrids via Lewis Acidic Molten Salts Etching for High Performance Symmetric Supercapacitors

“…The areal energy densities attained 103.3 μWh cm −2 at 0.8 mW cm −2 , among the best Ti 3 C 2 based supercapacitor (Figure 4 d). [34–38] It could maintain 44.9 μWh cm −2 at 8.0 mW cm −2 , revealing its ideal capacitive behavior and desirable fast charging/discharging property for power devices [39] . Nyquist plots were recorded and fitted, revealing a low interfacial R ct (Figure S17).…”

MXene‐Copper/Cobalt Hybrids via Lewis Acidic Molten Salts Etching for High Performance Symmetric Supercapacitors

“…The areal energy densities attained 103.3 mWh cm À2 at 0.8 mW cm À2 , among the best Ti 3 C 2 based supercapacitor (Figure 4 d). [34][35][36][37][38] It could maintain 44.9 mWh cm À2 at 8.0 mW cm À2 , revealing its ideal capacitive behavior and desirable fast charging/discharging property for power devices. [39] Nyquist plots were recorded and fitted, revealing a low interfacial R ct (Figure S17).…”