scholarly journals Sintered polymeric binders for Li-ion battery alloy anodes

2018 ◽  
Vol 96 (7) ◽  
pp. 765-770 ◽  
Author(s):  
T.D. Hatchard ◽  
R.A. Fielden ◽  
M.N. Obrovac
Keyword(s):  
Polyvinylidene Fluoride ◽  
High Performance ◽  
Cycling Performance ◽  
Superior Performance ◽  
Capacity Fade ◽  
High Carbon ◽  
Carbon Yield ◽  
Carbon Coatings ◽  
Alloy Particles ◽  
Polymeric Binders

The cycling performance in lithium half cells of Si alloy electrodes with polyvinylidene fluoride or polyimide binders were evaluated after the electrodes were cured at temperatures below and above the binder carbonization temperature. After carbonization, the cycling performance of electrodes using polyvinylidene fluoride binder improved considerably but still suffered from capacity fade. Electrodes with carbonized polyimide binder had superior performance and showed no capacity fade after 100 cycles. The superior performance of carbonized polyimide electrodes is thought to be related to polyimide’s high carbon yield upon heating, resulting in the formation of a uniform carbon coating on alloy surfaces. These results suggest that new high performance binders for alloy electrodes might be derived by the carbonization of polymers with a high carbon yield that lead to the formation of uniform carbon coatings on alloy particles.

scholarly journals Facile fabrication of hierarchical porous carbon for a high-performance electrochemical capacitor

RSC Advances ◽  
2017 ◽  
Vol 7 (73) ◽  
pp. 46329-46335 ◽  
Author(s):  
Guixiang Du ◽  
Qiuxiao Bian ◽  
Jingbo Zhang ◽  
Xinhui Yang
Keyword(s):  
Porous Carbon ◽  
High Performance ◽  
Rate Capability ◽  
Electrochemical Capacitor ◽  
High Specific Capacitance ◽  
Cycling Performance ◽  
Hierarchical Porous Carbon ◽  
Hierarchical Porous ◽  
Facile Fabrication ◽  
Rapid Pyrolysis

A facile and rapid pyrolysis method is developed for the synthesis of 3D hierarchical porous carbon, which exhibits a high specific capacitance, good rate capability and good cycling performance.

Low ECD High Performance Invert Emulsion Drilling Fluids: Lab Development and Field Deployment

2021 ◽  
Author(s):  
Vikrant Wagle ◽  
Abdullah Yami ◽  
Michael Onoriode ◽  
Jacques Butcher ◽  
Nivika Gupta
Keyword(s):  
High Performance ◽  
Filter Cake ◽  
Drilling Fluid ◽  
Field Performance ◽  
Superior Performance ◽  
Core Material ◽  
Drilling Fluids ◽  
Invert Emulsion ◽  
Field Deployment ◽  
Permeability Studies

Abstract The present paper describes the results of the formulation of an acid-soluble low ECD organoclay-free invert emulsion drilling fluid formulated with acid soluble manganese tetroxide and a specially designed bridging package. The paper also presents a short summary of field applications to date. The novel, non-damaging fluid has superior rheology resulting in lower ECD, excellent suspension properties for effective hole cleaning and barite-sag resistance while also reducing the risk of stuck pipe in high over balance applications. 95pcf high performance invert emulsion fluid (HPIEF) was formulated using an engineered bridging package comprising of acid-soluble bridging agents and an acid-soluble weighting agent viz. manganese tetroxide. The paper describes the filtration and rheological properties of the HPIEF after hot rolling at 300oF. Different tests such as contamination testing, sag-factor analysis, high temperature-high pressure rheology measurements and filter-cake breaking studies at 300oF were performed on the HPIEF. The 95pcf fluid was also subjected to particle plugging experiments to determine the invasion characteristics and the non-damaging nature of the fluids. The 95pcf HPIEF exhibited optimal filtration properties at high overbalance conditions. The low PV values and rheological profile support low ECDs while drilling. The static aging tests performed on the 95pcf HPIEF resulted in a sag factor of less than 0.53, qualifying the inherent stability for expected downhole conditions. The HPIEF demonstrated resilience to contamination testing with negligible change in properties. Filter-cake breaking experiments performed using a specially designed breaker fluid system gave high filter-cake breaking efficiency. Return permeability studies were performed with the HPIEF against synthetic core material, results of which confirmed the non-damaging design of the fluid. The paper thus demonstrates the superior performance of the HPIEF in achieving the desired lab and field performance.

Building sponge-like robust architectures of CNT–graphene–Si composites with enhanced rate and cycling performance for lithium-ion batteries

2015 ◽  
Vol 3 (7) ◽  
pp. 3962-3967 ◽  
Author(s):  
Xiaolei Wang ◽  
Ge Li ◽  
Fathy M. Hassan ◽  
Matthew Li ◽  
Kun Feng ◽  
...  
Keyword(s):  
Lithium Ion Batteries ◽  
Anode Materials ◽  
High Performance ◽  
Rate Capability ◽  
Lithium Ion ◽  
Cycling Performance ◽  
Cycling Stability ◽  
Great Promise ◽  
Practical Applications ◽  
Excellent Cycling Stability

High-performance robust CNT–graphene–Si composites are designed as anode materials with enhanced rate capability and excellent cycling stability for lithium-ion batteries. Such an improvement is mainly attributed to the robust sponge-like architecture, which holds great promise in future practical applications.

scholarly journals Design, fabrication and experimental studies of compliant flexure diaphragm for micro pump

2018 ◽  
Vol 7 (2.21) ◽  
pp. 66 ◽  
Author(s):  
R Roopa ◽  
P Navin Karanth ◽  
S M. Kulkarni
Keyword(s):  
Polyvinylidene Fluoride ◽  
High Performance ◽  
Experimental Studies ◽  
Single Layer ◽  
Operating Voltage ◽  
Driving Voltage ◽  
Element Analysis ◽  
Central Deflection ◽  
Large Numbers ◽  
Micro Pump

This study reports the performance of piezo actuated compliant flexure diaphragm for micropump and MEMS application. To achieve the high performance of diaphragm at the low operating voltage compliant flexure diaphragm design is introduced. Very limited work has done on the diaphragms of micropump. Large numbers of mechanical micropumps have used plane diaphragms. The central deflection of diaphragm plays an important role in defining the micropump performance. The flow rate of mechanical type micropump strongly depends on the central deflection of diaphragm. In this paper compliant flexure diaphragms are designed for micropump to achieve higher deflection at lower operating voltage. Finite element analysis of compliant flexure diaphragm with single layer PVDF (Polyvinylidene fluoride) actuator is simulated in COMSOL. Compliant flexure diaphragms with a different number of flexures are analyzed. The central deflection of compliant flexure diaphragms is measured for driving voltages of 90V to 140V in 10 steps. The deflection of the compliant flexure diaphragm mainly depends on flexure width and length, the number of flexures in the diaphragm, PVDF thickness, diaphragm thickness and driving voltage. Use of compliant flexure diaphragm for micropump will reduce the mass and driving voltage of micropump. An attempt is made to compare the results of compliant flexure diaphragms with plane diaphragms. From the experimental results it is noticed that the compliant flexure diaphragm deflection is twice that of the plane diaphragm at same driving voltage. Deflection of three flexure and four flexure compliant diaphragms is 10.5µm and 11.5µm respectively at 140V.  

Mild solution synthesis of graphene loaded with LiFePO4–C nanoplatelets for high performance lithium ion batteries

2015 ◽  
Vol 39 (2) ◽  
pp. 1094-1100 ◽  
Author(s):  
Muchun Liu ◽  
Yan Zhao ◽  
Sen Gao ◽  
Yan Wang ◽  
Yuexin Duan ◽  
...  
Keyword(s):  
Lithium Ion Batteries ◽  
Mild Solution ◽  
High Performance ◽  
Solution Treatment ◽  
Lithium Ion ◽  
Cycling Performance ◽  
Solution Synthesis ◽  
Microwave Assisted

Microwave-assisted solution treatment provides a simple and safe synthesis for nanomaterials and nanocomposites. LiFePO4–graphene–C nanoplatelets show excellent cycling performance.

scholarly journals Atomic Modulation of 3D Conductive Frameworks Boost Performance of MnO2 for Coaxial Fiber-Shaped Supercapacitors

2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Xiaona Wang ◽  
Zhenyu Zhou ◽  
Zhijian Sun ◽  
Jinho Hah ◽  
Yagang Yao ◽  
...  
Keyword(s):  
Energy Density ◽  
Specific Capacitance ◽  
High Performance ◽  
High Specific Capacitance ◽  
Superior Performance ◽  
High Mass ◽  
Mass Loading ◽  
Energy Storage Devices ◽  
Free Standing ◽  
Cell Potential

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.

Performance on an Adaptive Automated Team Tracking Task with Human and Computer Teammates

1997 ◽  
Vol 41 (1) ◽  
pp. 551-555 ◽  
Author(s):  
Kristin Krahl ◽  
Mark W. Scerbo
Keyword(s):  
Adaptive Systems ◽  
High Performance ◽  
Vertical Axis ◽  
Tracking Task ◽  
Superior Performance ◽  
Performance Skills ◽  
Group Assignment ◽  
Pursuit Tracking ◽  
Human Participants ◽  
High Level

The present study examined team performance on an adaptive pursuit tracking task with human-human and human-computer teams. The participants were randomly assigned to one of three team conditions where their partner was either a computer novice, computer expert, or human. Participants began the experiment with control over either the horizontal or vertical axis, but had the option of taking control of their teammate's axis if they achieved superior performance on the previous trial. A control condition was also run where a single participant controlled both axes. Performance was assessed by RMSE scores over 100 trials. The results showed that performance along the horizontal axis improved over the session regardless of the experimental condition, but the degree of improvement was dependent upon group assignment. Individuals working alone or paired with an expert computer maintained a high level of performance throughout the experiment. Those paired with a computer-novice or another human performed poorly initially, but eventually reached the level of those in the other conditions. The results showed that team training can be as effective as individual training, but that the quality of training is moderated by the skill level of one's teammate. Moreover, these findings suggest that task partitioning of high performance skills between a human and a computer is not only possible but may be considered a viable option in the design of adaptive systems.

scholarly journals CENTIMETRE-ACCURACY IN FORESTS AND URBAN CANYONS – COMBINING A HIGH-PERFORMANCE IMAGE-BASED MOBILE MAPPING BACKPACK WITH NEW GEOREFERENCING METHODS

2020 ◽  
Vol V-1-2020 ◽  
pp. 333-341
Author(s):  
S. Blaser ◽  
J. Meyer ◽  
S. Nebiker ◽  
L. Fricker ◽  
D. Weber
Keyword(s):  
Web Services ◽  
High Performance ◽  
Large Scale ◽  
Superior Performance ◽  
City Centre ◽  
Visual Localization ◽  
Mobile Mapping ◽  
Coordinate Measurement ◽  
Collaborative Processes ◽  
Mobile Mapping System

Abstract. Advances in digitalization technologies lead to rapid and massive changes in infrastructure management. New collaborative processes and workflows require detailed, accurate and up-to-date 3D geodata. Image-based web services with 3D measurement functionality, for example, transfer dangerous and costly inspection and measurement tasks from the field to the office workplace. In this contribution, we introduced an image-based backpack mobile mapping system and new georeferencing methods for capture previously inaccessible outdoor locations. We carried out large-scale performance investigations at two different test sites located in a city centre and in a forest area. We compared the performance of direct, SLAM-based and image-based georeferencing under demanding real-world conditions. Both test sites include areas with restricted GNSS reception, poor illumination, and uniform or ambiguous geometry, which create major challenges for reliable and accurate georeferencing. In our comparison of georeferencing methods, image-based georeferencing improved the median precision of coordinate measurement over direct georeferencing by a factor of 10–15 to 3 mm. Image-based georeferencing also showed a superior performance in terms of absolute accuracies with results in the range from 4.3 cm to 13.2 cm. Our investigations showed a great potential for complementing 3D image-based geospatial web-services of cities as well as for creating such web services for forest applications. In addition, such accurately georeferenced 3D imagery has an enormous potential for future visual localization and augmented reality applications.

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