Influence of pH on Electrochemical Performances of Iron Phosphate (FePO4•xH2O) Particles and LiFePO4/C Composites

2013 ◽  
Vol 643 ◽  
pp. 100-103 ◽  
Author(s):  
Yi Jie Gu ◽  
Peng Liu ◽  
Yun Bo Chen ◽  
Hong Quan Liu ◽  
Yan Min Wang ◽  
...  
Keyword(s):  
Raw Materials ◽  
Electronic Conductivity ◽  
Iron Phosphate ◽  
Electrochemical Performances ◽  
Galvanostatic Charge ◽  
High Electronic Conductivity ◽  
Electrochemical Capacity ◽  
Size And Morphology ◽  
Co Precipitation ◽  
Influence Of Ph

The effect of pH concentrations on the size and morphology of FePO4•xH2O particles synthesized in a hydrothermal reactor was investigated in this work. FePO4•xH2O was prepared through co-precipitation by employing Fe(NO3)3•9H2Oand H3PO4 as raw materials. The LiFePO4 obtained through lithiation of FePO4•xH2O by using glucose as a reducing agent at 700°C. The electrochemical performance of LiFePO4 powder synthesized at 700°C were evaluated using coin cells by galvanostatic charge/discharge .The results indicated that the synthesized LiFePO4/C composites (pH=2) showed a superior electrochemical capacity of 146 mAh/g and possessed a capacity favorable cycling maintenance at the 0.1C rate and high electronic conductivity.

Preparation and Electrochemical Performance of Mn3O4/GR Composites Electrode Material in Supercapacitors

2019 ◽  
Vol 807 ◽  
pp. 50-56
Author(s):  
Yun Long Zhou ◽  
Zhi Biao Hu ◽  
Li Mei Wu ◽  
Jiao Hao Wu
Keyword(s):  
Room Temperature ◽  
Raw Materials ◽  
Precipitation Method ◽  
Electrochemical Performances ◽  
Manganese Sulfate ◽  
X Ray Diffraction ◽  
X Ray ◽  
Co Precipitation ◽  
A Current ◽  
Discharge Test

Using hydrated manganese sulfate and general type graphene (GR) as raw materials, Mn3O4/GR composite has been successfully prepared by the liquid phase chemical co-precipitation method at room temperature. X-ray diffraction (XRD) was used to investigate the phase structure of Mn3O4powder and Mn3O4/GR composite; The electrochemical performances of the samples were elucidated by cyclic voltammetry and galvanostatic charge-discharge test in 0.5 mol/L Na2SO4electrolyte. The results show that the Mn3O4/GR composite possesses graphene phase and good reversibility; the composite also displays a specific capacitance of 318.8 F/g at a current density of 1 A/g.

Ni Doped LiMn2O4 Prepared by a Flameless Combustion Synthesis

2012 ◽  
Vol 625 ◽  
pp. 251-254 ◽  
Author(s):  
Gui Yang Liu ◽  
Bao Sen Wang ◽  
Ying He ◽  
Jun Ming Guo
Keyword(s):  
Combustion Synthesis ◽  
Raw Materials ◽  
Synthesis Method ◽  
Solution Combustion Synthesis ◽  
Electrochemical Performances ◽  
X Ray Diffraction ◽  
Galvanostatic Charge ◽  
Solution Combustion ◽  
Limn2o4 Spinel ◽  
X Ray

In this paper, LiNixMn2−xO4 materials were prepared by solution combustion synthesis method using acetic salts as raw materials and acetic acid as fuel. The phase structures are characterized by X-ray diffraction (XRD). Electrochemical performances of the materials are investigated by galvanostatic charge/discharge methods. XRD results revealed that the main phase of the products with increasing Ni3+ content is LiMn2O4, and there is a trace amount of Mn3O4 found in the product with Ni3+ content of 0.05. Electrochemical experiments showed that the capacity and the cyclability of the LiNixMn2−xO4 materials decrease with increasing Ni3+ content. Ni3+ doping has no significantly improvement for the capacity and the cyclability of the LiMn2O4 spinel.

scholarly journals High-Performance Lithium Sulfur Batteries Based on Multidimensional Graphene-CNT-Nanosulfur Hybrid Cathodes

Batteries ◽  
2021 ◽  
Vol 7 (2) ◽  
pp. 26
Author(s):  
Álvaro Doñoro ◽  
Álvaro Muñoz-Mauricio ◽  
Vinodkumar Etacheri
Keyword(s):  
High Performance ◽  
Coulombic Efficiency ◽  
Electronic Conductivity ◽  
Specific Capacity ◽  
Synthesis Method ◽  
Graphene Nanoplatelets ◽  
Practical Implementation ◽  
Electrochemical Performances ◽  
High Electronic Conductivity ◽  
Lithium Sulfur

Although lithium-sulfur (Li-S) batteries are one of the promising candidates for next-generation energy storage, their practical implementation is limited by rapid capacity fading due to lithium polysulfide (LiPSs) formation and the low electronic conductivity of sulfur. Herein, we report a high-performance lithium-sulfur battery based on multidimensional cathode architecture consisting of nanosulfur, graphene nanoplatelets (2D) and multiwalled carbon nanotubes (1D). The ultrasonic synthesis method results in the generation of sulfur nanoparticles and their intercalation into the multilayered graphene nanoplatelets. The optimized multidimensional graphene-sulfur-CNT hybrid cathode (GNS58-CNT10) demonstrated a high specific capacity (1067 mAh g−1 @ 50 mA g−1), rate performance (539 @ 1 A g−1), coulombic efficiency (~95%) and cycling stability (726 mAh g−1 after 100 cycles @ 200 mA g−1) compared to the reference cathode. Superior electrochemical performances are credited to the encapsulation of nanosulfur between the individual layers of graphene nanoplatelets with high electronic conductivity, and effective polysulfide trapping by MWCNT bundles.

Synthesis and Performances of a Fe-Site Doped Lithium Iron Phosphate

2013 ◽  
Vol 652-654 ◽  
pp. 877-881
Author(s):  
Hui Xie ◽  
Jian Zhuang Liu
Keyword(s):  
Lithium Iron Phosphate ◽  
Lithium Ion ◽  
Iron Phosphate ◽  
Electrochemical Performances ◽  
X Ray Diffraction ◽  
Electronic Conductivities ◽  
Structure Morphology ◽  
Electrochemical Capacity ◽  
Li Ion ◽  
Discharge Test

A Fe-site doped lithium phosphate LiFe0.99La0.01PO4 as cathode material for lithium ion battery was synthesized by solid-state reaction. The crystalline structure, morphology of particles and electrochemical performances of the sample were investigated by X-ray diffraction, scanning electron microscopy, charge-discharge test and cyclic voltammetry. The results show that the small LiFe0.99La0.01PO4 particles are simple pure olive-type phase structure with uniformly distribution of gain size. The LiFe0.99La0.01PO4 obtained has proper electrochemical capacity, good cycle ability and rate performances. Such an excellent electrochemical characteristic should be partially related to the enhanced electronic conductivities and probably the better mobility of Li ion in the crystal of the doped sample.

scholarly journals Enhanced electrochemical performances of activated carbon (AC)-nickel-metal organic framework (SIFSIX-3-Ni) composite and ion-gel electrolyte based supercapacitor

2021 ◽  
Author(s):  
Kyu Seok Lee ◽  
Ye Ji Seo ◽  
Hyeon Taek Jeong
Keyword(s):  
Activated Carbon ◽  
Electrochemical Impedance ◽  
Metal Organic Framework ◽  
Gel Electrolyte ◽  
Electrochemical Performances ◽  
Galvanostatic Charge ◽  
Nickel Metal ◽  
Capacitive Behavior ◽  
Metal Organic ◽  
Ion Gel

AbstractIn this study, we investigated that the activated carbon (AC)-based supercapacitor and introduced SIFSIX-3-Ni as a porous conducting additive to increase its electrochemical performances of AC/SIFSIX-3-Ni composite-based supercapacitor. The AC/SIFSIX-3-Ni composites are coated onto the aluminum substrate using the doctor blade method and conducted an ion-gel electrolyte to produce a symmetrical supercapacitor. The electrochemical properties of the AC/SIFSIX-3-Ni composite-based supercapacitor are evaluated through cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and galvanostatic charge/discharge tests (GCD). The AC/SIFSIX-3-Ni composite-based supercapacitor showed reasonable capacitive behavior in various electrochemical measurements, including CV, EIS, and GCD. The highest specific capacitance of the AC/SIFSIX-3-Ni composite-based supercapacitor was 129 F g−1 at 20 mV s−1.

Preparation of High-Purity Ultrafine α-Al2O3 by Solid-State Reaction at Room Temperature

2008 ◽  
Vol 368-372 ◽  
pp. 683-685
Author(s):  
Cheng Wei Hao ◽  
Bo Lin Wu ◽  
Ji Yan Li
Keyword(s):  
Solid State ◽  
High Purity ◽  
Solid State Reaction ◽  
Room Temperature ◽  
Raw Materials ◽  
Phase Particle ◽  
Phase Transformation Temperature ◽  
Particle Size And Morphology ◽  
Size And Morphology ◽  
Α Al2o3

Ammonium aluminium carbonate hydroxide (AACH), with a small quantity of γ-AlOOH, was synthesized through solid-state reaction at room temperature using AlCl3·6H2O and NH4HCO3 as raw materials and polyethylene glycol (PEG-10000) as the dispersant. After calcined at 1100°C for 1.5h, α-Al2O3 powders with primary particle sizes of 20~30nm were obtained. The crystal phase, particle size and morphology of the high-purity ultrafine α-Al2O3 were characterized. The results showed that a small quantity of γ-AlOOH in the AACH decomposed and formed crystal seeds. The presence of crystal seeds reduced the nucleation activation energy and therefore reduced the phase transformation temperature.

scholarly journals Preparation of composite coagulant of PFM-PDMDAAC and its coagulation performance in treatment of landfill leachate

2015 ◽  
Vol 5 (2) ◽  
pp. 177-188 ◽  
Author(s):  
Simin Li ◽  
Yongkang Lv ◽  
Zhanmeng Liu
Keyword(s):  
Landfill Leachate ◽  
Raw Materials ◽  
Oxygen Demand ◽  
X Ray Diffraction ◽  
Mechanical Mixing ◽  
Coagulation Performance ◽  
Coagulation Mechanism ◽  
As Adsorption ◽  
Co Precipitation ◽  
Composite Coagulant

A novel inorganic–organic composite coagulant, poly-ferric-magnesium (PFM) polydimethyldiallylammonium chloride (PDMDAAC), was prepared using FeSO4, MgSO4 and PDMDAAC as raw materials and was introduced to treat landfill leachate. The coagulation performance of the new reagent was evaluated and compared with those of other coagulants. The new reagent was characterized in terms of the analysis of ferron-timed spectroscopy, X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). The coagulation mechanism was investigated by measuring the ζ-potential reduction and chemical oxygen demand removal at different dosages. Coagulation experiments revealed that the new reagent exhibited better coagulation performance compared with the simple PFM and the PFM + PDMDAAC. Ferron-timed spectroscopy showed that the new reagent exhibited increased effective polymer species concentration. XRD and FTIR spectroscopy showed that the new reagent was not a simple mechanical mixing of PFM and PDMDAAC, but a composite system with inorganic–organic complex interpenetration networks. The predominant coagulation mechanism of the new reagent was charge neutralization at low dosages, as well as adsorption bridging and co-precipitation netting at high dosages, when treating landfill leachate.

Preparation and Electrochemical Properties of LaMnO3 Powder as a Supercapacitor Electrode Material

2017 ◽  
Vol 727 ◽  
pp. 698-704 ◽  
Author(s):  
Xian Wei Wang ◽  
Xiao Er Wang ◽  
Hui Chao Zhang ◽  
Qian Qian Zhu ◽  
Dong Li Zheng ◽  
...  
Keyword(s):  
Cyclic Voltammetry ◽  
Electrochemical Properties ◽  
Electrode Material ◽  
Raw Materials ◽  
Sol Gel ◽  
Galvanostatic Charge ◽  
Supercapacitor Electrode ◽  
Lanthanum Manganate ◽  
Pure Phase ◽  
Charge Discharge

The structural and electrochemical properties of lanthanum manganate (LaMnO3) powder prepared by the sol-gel method are researched in this article. The powder calcined at 600 °C showed amorphous, and the powder calcined at 700-800 °C showed the pure phase of the LaMnO3. The grains with the size of about 80-120 nm were agglomerating together. Cyclic voltammetry and galvanostatic charge-discharge were used to characterize the electrochemical properties in alkaline environment. The electrochemical properties calcined at 700 °C showed a specific capacitance of 73 F/g at the current density of 0.5 A/g. The raw materials for preparing the LaMnO3 powder are cheap, and the operation method is simple.

scholarly journals Pre-treatment of desalination feed seawater by Jordanian Tripoli, Pozzolana, and Feldspar: Batch experiments

2011 ◽  
Vol 17 (2) ◽  
pp. 163-171 ◽  
Author(s):  
Aiman Al-Rawajfeh ◽  
Khaldoon Al-Whoosh ◽  
Dwairi Al ◽  
Ahmad Al-Maaberah ◽  
Amer Tarawneh
Keyword(s):  
Layered Double Hydroxide ◽  
Metal Ion ◽  
Raw Materials ◽  
Batch Experiments ◽  
Initial Concentration ◽  
Considerable Potential ◽  
Ion Concentrations ◽  
Pre Treatment ◽  
Co Precipitation ◽  
Double Hydroxide

In this research, composites of layered double hydroxide (LDH) with three Jordanian natural raw materials; Tripoli (T), Pozzolana (P) and Feldspar (F) were prepared by co-precipitation and have been used for feed seawater pre-treatment. The data reveals that percent adsorption decreased with increase in initial concentration, but the actual amount of adsorbed ions per unit mass of LDH/T-P-F increased with increase in metal ion concentrations. The values of ?Go were negative and within 21 to 26 KJ/mol, while the values of ?Ho and ?So were positive and within the range of 0.1 to 25 KJ/mol. The values of ?H?, ?S?, and ?G? indicate the favorability of physisorption and show that the LDH/T-P-F composites have a considerable potential as adsorbents for the removal of ions from seawater.

Quantum transport, electronic properties and molecular adsorptions in graphene

2021 ◽  
Vol 35 (08) ◽  
pp. 2130001
Author(s):  
Yoshitaka Fujimoto
Keyword(s):  
Electronic Properties ◽  
Quantum Transport ◽  
Density Functional ◽  
Field Effect Transistors ◽  
Electronic Conductivity ◽  
Volume Ratio ◽  
Functional Study ◽  
Sensor Applications ◽  
Sensing Applications ◽  
High Electronic Conductivity

Molecular sensor applications are used in different fields including environmental monitoring and medical diagnosis. Graphene, a single atomic layer consisting of the hexagonally arranged carbon material, is one of the most promising materials for ideal channels in field-effect transistors to be used as electronic sensing applications owing to its lightweight, mechanical robustness, high electronic conductivity and large surface-to-volume ratio. This paper provides a review of molecular adsorptions, electronic properties and quantum transport of graphene based on the first-principles density-functional study. The adsorption properties of environmentally polluting or toxic molecules and electronic transport of graphene are revealed. The possibility of detecting these molecules selectively is also discussed for designing the graphene-based sensor applications.

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