Hierarchical ultrathin NiAl layered double hydroxide nanosheet arrays on carbon nanotube paper as advanced hybrid electrode for high performance hybrid capacitors

Abstract

To effectively improve the power density and rate capability of layered double hydroxide (LDH) based supercapacitors, a hybrid supercapacitor (HSC) comprising of hierarchical ultrathin NiAl-LDH nanosheet arrays on carbon nanotube paper (CNP-LDH) is developed with porous graphene nanosheets as the negative electrode for the first time. SEM image shows that hierarchical NiAl LDH nanosheet arrays are assembled by numerous ultrathin nanosheets with thickness of a few to tens of nanometers. Remarkably, with an operating voltage of 1.6 V, the * Corresponding author.E-mail address: bizhui@umac.mo (Kwun Nam Hui), k.hui@uea.ac.uk (Kwan San Hui) 1 These authors contributed equally to this work. Even at a fast discharging time of 3.9 s, a high energy density (23.3 Wh kg -1 ) could also be retained at a power density of 21.5 kW kg -1 . Moreover, the HSC exhibits cycling stability with a retention rate of 78% after 5000-cycle charge-discharge test at 5 A g -1 . The results inspire us to propose our high-performance CNP-LDH as a promising electrode for energy storage applications.

Accelerating the Photocatalytic Degradation of Green Dye Pollutants by Using a New Coating Technique for Carbon Nanotubes with Nanolayered Structures and Nanocomposites

“…The changes in the characteristics pectral bands of the hydroxyl groups and carbonate anionso fL DHs with andw ithout CNTsr eflect the effective role of CNTsi nc ontrolling the morphologyo fL DHs, and indicatet he existence of chemical interactions between the CNTsa nd LDHs. [29] This may be explained by the presence of hydrogen bonds between the hydroxyl groups of the LDHs and the functional groups of CNTs (-COOH). This speculation could be confirmed by the broadness of the OÀHb and and as houldera ta round 2940 cm À1 owing to hydrogen-bonding interactions.…”

“…Li et al [27] and Zhang et al [28] used LDH/CNTsa sc atalystsf or oxidation and reductionr eactions. Zhang et al [29] synthesized ah ybrid supercapacitorc omprised of Ni-Al LDHs attachedt oC NTs. In the field of environmental remediation, studies that depend on ac ombination of CNTs and LDHs are rare because of unattractive results published by Wang et al [30] and Lan et al, [31] who supported Zn-Al LDHs particles over CNTsbut did not get good results for the photocatalytic degradation of pollutants.…”

Swift tuning from spherical molybdenum microspheres to hierarchical molybdenum disulfide nanostructures by switching from solvothermal to hydrothermal synthesis route

“…At high magnification, as seen in Fig. 2d, each marigold flower appears to be made up of petal-like nanostructures [27, 28]. Each petal has thickness ~10–20 nm.…”

Preparation of NiAl double hydroxide@polypyrrole materials for high‐performance supercapacitors

“…Electrode materials are often critical to determine the charge storage contributions and electrochemical performances . Among the various supercapacitor electrode materials, the layered double hydroxides (LDH) containing transition metal elements have received interest due to low cost, high theoretical capacitance, fast redox kinetics, and environmentally friendly features . So, the LDH are regarded as promising electrode materials in high‐performance supercapacitor applications.…”

“…The Ni 2 MgAl‐LDH afforded a high specific capacitance of 219.2 mA∙h∙g −1 at 1 A∙g −1 , while the NiV‐LDH provided a higher specific capacitance with 711 C∙g −1 at 1 A∙g −1. In fact, the LDH still encounters with its intrinsic low electrical conductivity and easy aggregation, leading in low‐rate performance of supercapacitors . In order to avoid the above drawbacks, the LDH‐based composites incorporated with organic conducting polymers, such as polyaniline (PANI) and polypyrrole (PPy), are fabricated to improve the conductivity and increase the monodispersity of the LDH materials.…”