Highly flexible and mechanically strong polyaniline nanostructure @ aramid nanofiber films for free-standing supercapacitor electrodes

Nanoscale ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 5507-5520 ◽  
Author(s):  
Qing Yin ◽  
Hongbing Jia ◽  
Amel Mohamed ◽  
Qingmin Ji ◽  
Liu Hong

The excellent integration of high specific capacitance and superior mechanical properties for flexible electrode can be achieved by the combination of aramid nanofiber and polyaniline.

2021 ◽  
pp. 095400832110231
Author(s):  
Fengyan Lv ◽  
Shanxin Xiong ◽  
Xiaoqin Wang ◽  
Jia Chu ◽  
Runlan Zhang ◽  
...  

Free-standing flexible supercapacitive electrodes have practical application for wearable energy storage devices. In this paper, graphene paper (GP), a flexible electrode substrate, was prepared by one-step reduction of graphene oxide (GO) using HI solution. GP can be used independently as a flexible electrode with specific capacitance of 227 F/g. In order to make up for the shortage of GP specific capacitance storage, polyaniline (PANI) with high specific capacitance and good electrical conductivity was selected to composite with GP by electrochemical polymerization approach. This method to fabricate electrode material by direct electrochemical polymerization avoids the use of conductive binder and organic solvent. Owing to the specific capacitance contribution of PANI and GP, the PANI/GP composites exhibit higher specific capacitance when the polymerization time is 30 s and the polymerization voltage is 0.8 V. At 1 A/g current density, the specific capacitance of composite is up to 759 F/g, which is 3.34 times of neat GP.


2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Xiaona Wang ◽  
Zhenyu Zhou ◽  
Zhijian Sun ◽  
Jinho Hah ◽  
Yagang Yao ◽  
...  

Abstract Coaxial fiber-shaped supercapacitors are a promising class of energy storage devices requiring high performance for flexible and miniature electronic devices. Yet, they are still struggling from inferior energy density, which comes from the limited choices in materials and structure used. Here, Zn-doped CuO nanowires were designed as 3D framework for aligned distributing high mass loading of MnO2 nanosheets. Zn could be introduced into the CuO crystal lattice to tune the covalency character and thus improve charge transport. The Zn–CuO@MnO2 as positive electrode obtained superior performance without sacrificing its areal and gravimetric capacitances with the increasing of mass loading of MnO2 due to 3D Zn–CuO framework enabling efficient electron transport. A novel category of free-standing asymmetric coaxial fiber-shaped supercapacitor based on Zn0.11CuO@MnO2 core electrode possesses superior specific capacitance and enhanced cell potential window. This asymmetric coaxial structure provides superior performance including higher capacity and better stability under deformation because of sufficient contact between the electrodes and electrolyte. Based on these advantages, the as-prepared asymmetric coaxial fiber-shaped supercapacitor exhibits a high specific capacitance of 296.6 mF cm−2 and energy density of 133.47 μWh cm−2. In addition, its capacitance retention reaches 76.57% after bending 10,000 times, which demonstrates as-prepared device’s excellent flexibility and long-term cycling stability.


2021 ◽  
Vol 7 (2) ◽  
pp. 46
Author(s):  
Siret Malmberg ◽  
Mati Arulepp ◽  
Krista Laanemets ◽  
Maike Käärik ◽  
Ann Laheäär ◽  
...  

The aim of this study was to investigate the electrochemical behaviour of aqueous electrolytes on thin-layer (20 µm) nanoporous carbide-derived carbon (CDC) composite fibrous directly electrospun electrodes without further carbonisation. There have been previously investigated fibrous electrodes, which are produced by applying different post-treatment processes, however this makes the production of fibrous electrodes more expensive, complex and time consuming. Furthermore, in the present study high specific capacitance was achieved with directly electrospun nanoporous CDC-based fibrous electrodes in different neutral aqueous electrolytes. The benefit of fibrous electrodes is the advanced mechanical properties compared to the existing commercial electrode technologies based on pressure-rolled or slurry-cast powder mix electrodes. Such improved mechanical properties are preferred in more demanding applications, such as in the space industry. Electrospinning technology also allows for larger electrode production capacities without increased production costs. In addition to the influence of aqueous electrolyte chemical composition, the salt concentration effects and cycle stability with respect to organic electrolytes are investigated. Cyclic voltammetry (CV) measurements on electrospun electrodes showed the highest capacitance for asymmetrical cells with an aqueous 1 M NaNO3-H2O electrolyte. High CV capacitance was correlated with constant current charge–discharge (CC) data, for which a specific capacitance of 191 F g−1 for the positively charged electrode and 311 F g−1 for the negatively charged electrode was achieved. The investigation of electrolyte salt concentration on fibrous electrodes revealed the typical capacitance dependence on ionic conductivity with a peak capacitance at medium concentration levels. The cycle-life measurements of selected two-electrode test cells with aqueous and non-aqueous electrolytes revealed good stability of the electrospun electrodes.


Molecules ◽  
2021 ◽  
Vol 26 (16) ◽  
pp. 4891
Author(s):  
Xiuya Wang ◽  
Ke Wan ◽  
Pengbo Xie ◽  
Yuanyuan Miao ◽  
Zhenbo Liu

With increasing energy demand driving the need for eco-friendly and efficient energy storage technology, supercapacitors are becoming increasingly prevalent in wearable devices because of their portability and stability. The performance of these supercapacitors is highly dependent on the choice of electrode material. The high capacitance and mechanical properties needed for these materials can be achieved by combining graphene’s stable electrical properties with renewable cellulose’s excellent mechanical properties into porous aerogels. In this study, graphene-cellulose hydrogels were prepared by a one-step hydrothermal method, with porous, ultra-light, and mechanically strong graphene-cellulose aerogels then prepared by freeze-drying. These composite aerogels possess excellent mechanical strength and high specific capacitance, capable of bearing about 1095 times the pressure of their own weight. Electrochemical tests show the specific capacitance of these composite aerogels can reach 202 F/g at a scanning rate of 5 mA/cm2. In view of their high surface area and fast charge transport provided by their 3D porous structure, graphene-cellulose aerogels have great potential as sustainable supercapacitor electrodes.


2019 ◽  
Author(s):  
Amalia Rapakousiou ◽  
Alejandro López-moreno ◽  
Belén Nieto-Ortega ◽  
M. Mar Bernal ◽  
Miguel A. Monclús ◽  
...  

We introduce poly(1,6-pyrene terephthalamide) polymer (PPyrTA) as an aromatic polyamide analogue of poly(p-phenylene terephthalamide) (PPTA), also known as Kevlar®. This work shows that the incorporation of polycyclic aromatic pyrene moieties improves drastically the mechanical properties of the polymeric structure, increasing elastic nanoindentation-determined modulus and hardness by factors of 1.9 and 4.3, respectively. Liquid deprotonated dispersions of PPyrTA nanofibers were used as nanoscale building block for producing large-surface, free-standing polymer macroscopic nanofilms. This 2D assembly leads to further significant improvements in reduced modulus and hardness (more than twice) compared to the starting polymer macroscale fibres, due to a better re-organizational arrangement of the PPyrTA nanofibers in the nanofilms, formed under 2D spatial confinement.


Author(s):  
Romaneh Jalilian ◽  
David Mudd ◽  
Neil Torrez ◽  
Jose Rivera ◽  
Mehdi M. Yazdanpanah ◽  
...  

Abstract The sample preparation for transmission electron microscope can be done using a method known as "lift-out". This paper demonstrates a method of using a silver-gallium nanoneedle array for a quicker sharpening process of tungsten probes with better sample viewing, covering the fabrication steps and performance of needle-tipped probes for lift-out process. First, an array of high aspect ratio silver-gallium nanoneedles was fabricated and coated to improve their conductivity and strength. Then, the nanoneedles were welded to a regular tungsten probe in the focused ion beam system at the desired angle, and used as a sharp probe for lift-out. The paper demonstrates the superior mechanical properties of crystalline silver-gallium metallic nanoneedles. Finally, a weldless lift-out process is described whereby a nano-fork gripper was fabricated by attaching two nanoneedles to a tungsten probe.


2020 ◽  
Vol 13 (02) ◽  
pp. 2051007
Author(s):  
Jie Dong ◽  
Qinghao Yang ◽  
Qiuli Zhao ◽  
Zhenzhong Hou ◽  
Yue Zhou ◽  
...  

Electrode materials with a high specific capacitance, outstanding reversibility and excellent cycle stability are constantly pursued for supercapacitors. In this paper, we present an approach to improve the electrochemical performance by combining the advantages of both inorganic and organic. Ni-MnO2/PANi-co-PPy composites are synthesized, with the copolymer of aniline/pyrrole being coated on the surface of Ni-doped manganese dioxide nanospheres. The inorganic–organic composite enables a substantial increase in its specific capacitance and cycle stability. When the mass ratio of Ni-MnO2 to aniline and pyrrole mixed monomer is 1:5, the composite delivers high specific capacitance of 445.49[Formula: see text]F/g at a scan rate of 2[Formula: see text]mV/s and excellent cycle stability of 61.65% retention after 5000 cycles. The results indicate that the Ni-MnO2/PANi-co-PPy composites are promising electrode materials for future supercapacitors application.


Sign in / Sign up

Export Citation Format

Share Document