Electrochemical performances of pyrolytic-cellulose for lithium and sodium ion batteries anode

2020 ◽  
Vol 10 (10) ◽  
pp. 1685-1691
Author(s):  
Lingfang Li ◽  
Dan Chen ◽  
Sichao Su ◽  
Bin Zeng

At present, due to the depletion of fossil fuels and increasingly serious environmental problems, more and more attention has been paid to the development and application of functional nanostructured materials as renewable energy storage materials. Herein, lithium and sodium storage properties of hard carbons (HC) prepared by pyrolyzing cellulose were investigated. The orderliness and bonding mode of hard carbon were analyzed by X-Ray Diffraction and X-ray Photoelectron Spectroscopy. Electrochemical properties were characterized by Cyclic Voltammetry, electrochemical Impedance Spectroscopy and charge–discharge test. Results showed that the cellulose-derived hard carbon had good lithium and sodium storage performance. The charge–discharge capacity was about 400 mAh/g and 240 mAh/g, respectively, at a current density of 0.2 A/g, and capacity was also stable under high current density of 2 A/g.

2019 ◽  
Vol 32 (3) ◽  
pp. 258-267 ◽  
Author(s):  
Jia Chu ◽  
Xue Li ◽  
Qiaoqin Li ◽  
Jing Ma ◽  
Bohua Wu ◽  
...  

Polyaniline nanowires (PANI NWs) were synthesized under different temperatures through a facile hydrothermal method and used as electrodes for high-performance pseudocapacitor. The resulting samples were analyzed by X-ray diffraction, Fourier transform infrared spectroscopy, Raman spectroscopy, scanning electron micrographs, thermogravimetric analysis, and X-ray photoelectron spectroscopy. Electrochemical properties of these PANI electrodes are studied by cyclic voltammetry, galvanostatic charge–discharge test, and electrochemical impedance spectroscopy in 0.5M H2SO4 aqueous solution. The highest specific capacitance is obtained on the PANI NWs synthesized under 80°C (PANI-80) with 540.0 F g−1 at current density of 0.5 A g−1 accompanied with 82% specific capacitance retention after 1000 charge discharge cycles at 5 A g−1 current density.


Batteries ◽  
2018 ◽  
Vol 4 (4) ◽  
pp. 71 ◽  
Author(s):  
Yusuke Abe ◽  
Tomoaki Saito ◽  
Seiji Kumagai

Two prelithiation processes (shallow Li-ion insertion, and thrice-repeated deep Li-ion insertion and extraction) were applied to the hard carbon (HC) negative electrode (NE) used in lithium-ion batteries (LIBs). LIB full-cells were assembled using Li(Ni0.5Co0.2Mn0.3)O2 positive electrodes (PEs) and the prelithiated HC NEs. The assembled full-cells were charged and discharged under a low current density, increasing current densities in a stepwise manner, and then constant under a high current density. The prelithiation process of shallow Li-ion insertion resulted in the high Coulombic efficiency (CE) of the full-cell at the initial charge-discharge cycles as well as in a superior rate capability. The prelithiation process of thrice-repeated Li-ion insertion and extraction attained an even higher CE and a high charge-discharge specific capacity under a low current density. However, both prelithiation processes decreased the capacity retention during charge-discharge cycling under a high current density, ascertaining a trade-off relationship between the increased CE and the cycling performance. Further elimination of the irreversible capacity of the HC NE was responsible for the higher utilization of both the PE and NE, attaining higher initial performances, but allowing the larger capacity to fade throughout charge-discharge cycling.


2018 ◽  
Vol 10 (3) ◽  
pp. 358-364 ◽  
Author(s):  
Chao Pan ◽  
Hongyu Sun ◽  
Jingyi Gao ◽  
Yucai Hu ◽  
Jing Wang

We introduced a simple method to construct novel three-dimensional (3D) flexible hierarchical nanocomposites by combining (1D) NiCo2O4 nanowires with 2D reduced graphene oxide (rGO) sheets. The hierarchical nanocomposite structure of rGO-wrapped NiCo2O4 (rGO-NiCo2O4) was confirmed by X-ray diffraction (XRD), Raman spectra, scanning electron microscopy (SEM), transmission electron microscope (TEM), and X-ray photoelectron spectroscopy (XPS). The results indicated that NiCo2O4 nanowires were successfully wrapped in rGO and the morphology of the rGO-NiCo2O4 showed a three-dimensional porous structure with NiCo2O4 being homogeneously distributed in the rGO. Given their apparent advantages, these two different nanostructures were evaluated as electrodes for high-performance supercapacitors. These electrodes exhibited a high capacitance of 1824.8 F·g–1 at a current density of 0.5 A·g–1, and an excellent cycling performance extending to 5000 cycles at a high current density of 4 A·g–1. Our results clearly demonstrate that rGO sheets on NiCo2O4 nanowires can substantially improve the capacitive performance of materials and ultimately increase the cycling stability of supercapacitors. The hierarchical binary nanocomposites show excellent electrochemical properties for energy storage applications, evidencing their potential application as supercapacitors.


Polymers ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2076 ◽  
Author(s):  
Junfeng Zhu ◽  
Ting Zhu ◽  
Huan Tuo ◽  
Wanbin Zhang

A novel nitroxyl radical polymer poly(TEMPO-acrylamide-co-sodium styrene sulfonate) (abbreviated as poly(TAm-co-SSS)) was synthesized using 4-acrylamido-2,2,6,6- tetramethylpiperidine (AATP) copolymerized with styrene sulfonate sodium (SSS). AATP was synthesized through a substitution reaction of acryloyl chloride. Meanwhile, poly(4-acrylamido-2,2,6,6-tetramethylpiperidine-1-nitroxyl radical) (PTAm) was prepared as a control sample. Then, the structures of products were characterized by nuclear magnetic resonance spectroscopy (1H-NMR), Fourier transform infrared spectroscopy (FT-IR), high performance liquid chromatography-mass spectrometry (HPLC-MS), differential scanning calorimetry (DSC), X-Ray photoelectron spectroscopy (XPS), and electron paramagnetic resonance (EPR), respectively. Additionally, the electrochemical impedance spectra (EIS) and the charge-discharge cycling properties were studied. The results demonstrated that the poly(TAm-co-SSS) with the side group of sodium sulfonate adjacent to TEMPO group exhibits a better charge-discharge cycling stability than that of the PTAm. Moreover, the charge specific capacity of the poly(TAm-co-SSS) is larger than that of the PTAm. Besides, the first coulombic efficiency of poly(TAm-co-SSS) is higher in comparison with that of PTAm. These superior electrochemical performances were ascribed to the synergistic effect of sulfonate ions group and nitroxyl radical structure, which benefits the improvement of charge carrier transportation of the nitroxyl radical polymers. Consequently, the nitroxyl radical poly(TAm-co-SSS) is promising for use in organic radical battery materials, based on the good electrochemical properties.


2012 ◽  
Vol 20 ◽  
pp. 53-60 ◽  
Author(s):  
Zan Wang ◽  
Xin Wang ◽  
Yun Xiao Zhao ◽  
Cui Mei Zhao ◽  
Wei Tao Zheng

Nanostructured MnOx/Ni (OH)2 composites have been electrodeposited on Ni foam for synthesis of a binder-free electrode for electrochemical capacitors with high specific capacitance and stable electrochemical properties. The microstructure, morphology and chemical composition were characterized by X-ray diffraction, scanning electron microscopy and X-ray photoelectron spectroscopy. Cyclic voltammetry and galvanostatic charge/discharge measurements were applied to investigate the electrochemical capacitance of the electrode active materials. The results indicated that MnOx acted as a template for growth of Ni (OH)2 with an inter-connected 3D porous network nanostructure. A maximum capacitance value of 2334 F/g at current density of 5 A/g in 1 M KOH electrolyte was achieved, much higher than that of pure Ni (OH)2 and MnOx (992 and 179 F/g, respectively). Moreover, in the charge/discharge process at even larger current density of 20 A/g, the electrode could maintain 82.8 % of the initial specific capacitance after 500 cycles, higher than that of pure Ni (OH)2 (only 46.6% remains). The enhanced capacitance performance was attributed to the synergic effect between the respective single oxides.


Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6672
Author(s):  
Jimin Lee ◽  
Sanghyuk Park ◽  
Mincheol Beak ◽  
Sang Ryul Park ◽  
Ah Reum Lee ◽  
...  

In order to examine the effect of excessive sulfate in the leachate of spent Li-ion batteries (LIBs), LiNi1/3Co1/3Mn1/3O2 (pristine NCM) and sulfate-containing LiNi1/3Co1/3Mn1/3O2 (NCMS) are prepared by a co-precipitation method. The crystal structures, morphology, surface species, and electrochemical performances of both cathode active materials are studied by scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and charge-discharge tests. The XRD patterns and XPS results identify the presence of sulfate groups on the surface of NCMS. While pristine NCM exhibits a very dense surface in SEM images, NCMS has a relatively porous surface, which could be attributed to the sulfate impurities that hinder the growth of primary particles. The charge-discharge tests show that discharge capacities of NCMS at C-rates, which range from 0.1 to 5 C, are slightly decreased compared to pristine NCM. In dQ/dV plots, pristine NCM and NCMS have the same redox overvoltage regardless of discharge C-rates. The omnipresent sulfate due to the sulfuric acid leaching of spent LIBs has a minimal effect on resynthesized NCM cathode active materials as long as their precursors are adequately washed.


Nanomaterials ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1662
Author(s):  
Junming Xu ◽  
Mengxia Tang ◽  
Zhengming Hu ◽  
Xiaoping Hu ◽  
Tao Zhou ◽  
...  

For conventional synthesis of Ni(OH)2/graphene hybrids, oxygen-containing functional groups should be firstly introduced on graphene to serve as active sites for the anchoring of Ni(OH)2. In this work, a method for growing Ni(OH)2 nanosheets on multilayer graphene (MLG) with molecular connection is developed which does not need any pre-activation treatments. Moreover, Ni(OH)2 nanosheets can be controlled to stand or lie on the surface of MLG. The prepared hybrids were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The growth processes are suggested according to their morphologies at different growth stages. The enhanced electrochemical performances as supercapacitor electrode materials were confirmed by cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD) techniques. Ni(OH)2 nanosheets standing and lying on MLG show specific capacities of 204.4 mAh g−1 and 131.7 mAh g−1, respectively, at 1 A g−1 based on the total mass of the hybrids and 81.5% and 92.8% capacity retention at a high current density of 10 A g−1, respectively. Hybrid supercapacitors with as-prepared hybrids as cathodes and activated carbon as anode were fabricated and tested.


Coatings ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 837
Author(s):  
Liting Mu ◽  
Zhen Ma ◽  
Jingyan Wang ◽  
Shidan Yuan ◽  
Muqin Li

Bone tissue repair materials can cause problems such as inflammation around the implant, slow bone regeneration, and poor repair quality. In order to solve these problems, a coating was prepared by ultrasonic micro-arc oxidation and self-assembly technology on a pure magnesium substrate. We studied the effect of berberine on the performance of the ultrasonic micro-arc oxidation/polylactic acid and glycolic acid copolymer/berberine (UMAO/PLGA/BR) coating. The chemical and morphological character of the coating was analyzed using scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The corrosion properties were studied by potentiodynamic polarization and electrochemical impedance spectroscopy in a simulated body fluid. The cumulative release of drugs was tested by high-performance liquid chromatography. The results indicate that different amounts of BR can seal the corrosion channel to different extents. These coatings have a self-corrosion current density (Icorr) at least one order of magnitude lower than the UMAO coatings. When the BR content is 3.0 g/L, the self-corrosion current density of the UMAO/PLGA/BR coatings is the lowest (3.14 × 10−8 A/cm2) and the corrosion resistance is improved. UMAO/PLGA/BR coatings have excellent biological activity, which can effectively solve the clinical problem of rapid degradation of pure magnesium and easy infection.


Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1188
Author(s):  
Badar Minhas ◽  
Sahib Dino ◽  
Yu Zuo ◽  
Hongchang Qian ◽  
Xuhui Zhao

By anodization and thermal oxidation at 600 °C, an oxide layer on Ti with excellent corrosion resistance in strong acid solutions was prepared. The structural properties of TiO2 films before and after thermal oxidation were investigated with methods of Scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XRD) and X-ray diffraction (XPS). The electrochemical characterization was recorded via electrochemical impedance spectroscopy, potentiodynamic polarization and Mott–Schottky methods. XRD results show that a duplex rutile/anatase structure formed after oxidation, and the amount of anatase phase increased as the treatment time was prolonged from 3 to 9 h. XPS analysis indicates that as the thermal oxidation time increased, more Ti vacancies were present in the titanium oxide films, with decreased donor concentration. Longer thermal oxidation promoted the formation of hydroxides of titanium on the surface, which is helpful to improve the passive ability of the film. The anodized and thermally oxidized Ti samples showed relatively high corrosion resistance in 4 M HCl and 4 M H2SO4 solutions at 100 ± 5 °C. The passive current density values of the thermally oxidized samples were five orders of magnitude under the testing condition compared with that of the anodized sample. With the oxidation time prolonged, the passive current density decreased further to some extent.


Author(s):  
Ke Qu ◽  
Yuqi Bai ◽  
Miao Deng

Abstract The ever-increasing need for small and lightweight power sources for use in portable or wearable electronic devices has spurred the development of supercapacitors as a promising energy storage and conversion system. In this work, a simple, facile and easy-to-practice method has been developed to employ carbon paper (CP) as the support to coat molybdenum disulfide (MoS2) and graphene oxide (GO), followed by electrodeposition of polyaniline (PANI) to render CP/MoS2-GO-PANI. The preparation parameters, such as amounts of MoS2, GO and number of aniline electropolymerization cycles, have been optimized to render CP/MoS2-GO-PANI the best capacitive performance. The as-prepared optimal CP/MoS2-GO-PANI is characterized by X-ray powder diffraction, scanning electron microscopy, energy-dispersive spectroscopy, and X-ray photoelectron spectroscopy. The supercapacitive properties of CP/MoS2-GO-PANI as an electrode have been evaluated electrochemically via cyclic voltammetry, galvanostatic charge/discharge, and electrochemical impedance spectroscopy testing. CP/MoS2-GO-PANI delivers a specific capacitance of 255.1 F/g at 1.0 A/g and exhibits excellent rate capability under larger current densities. Moreover, a symmetrical supercapacitor is assembled and three are connected in series to power a light-emitting diode for ~15 minutes, demonstrating the promising application potential of CP/MoS2-GO-PANI-based supercapacitor.


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