The Effect of Different Li(Ni1-x-yMnxCoy)O2Positive Electrode Materials and Coatings on Parasitic Heat Flow as Measured by Isothermal Microcalorimetry, Ultra-High Precision Coulometry and Long Term Cycling

2017 ◽  
Vol 164 (6) ◽  
pp. A1203-A1212 ◽  
Author(s):  
S. L. Glazier ◽  
K. J. Nelson ◽  
J. P. Allen ◽  
J. Li ◽  
J. R. Dahn
Keyword(s):  
Heat Flow ◽  
High Precision ◽  
Electrode Materials ◽  
Isothermal Microcalorimetry

scholarly journals Measuring Parasitic Heat Flow in LiFePO4/Graphite Cells Using Isothermal Microcalorimetry

2021 ◽  
Author(s):  
Eric Logan ◽  
Jeff R Dahn
Keyword(s):  
Heat Flow ◽  
Lattice Gas ◽  
Electrode Materials ◽  
Mean Field Theory ◽  
Mean Field ◽  
Isothermal Microcalorimetry ◽  
Electrolyte Additives ◽  
Ppm Level ◽  
In Cells

Abstract Isothermal microcalorimetry has previously been used to probe parasitic reactions in Li-ion batteries, primarily studying Li[NixMnyCo1-x-y]O2 (NMC) positive electrode materials. Here, isothermal microcalorimetry techniques are adopted to study parasitic reactions in LiFePO4 (LFP)/graphite cells. Features in the heat flow from graphite staging transitions were identified, and the associated heat flow was calculated using simple lattice-gas mean-field theory arguments, finding good agreement with experimentally measured values. Parasitic heat flow was measured in LFP/graphite pouch cells with different electrolyte additives. In an electrolyte without additives, a massive parasitic heat flow was measured suggesting a shuttle reaction unique to the LFP/graphite system. In cells containing electrolyte additives, parasitic heat flow agreed well with long-term cycling results, confirming the value of this technique to rank the lifetime of LFP/graphite cells with different electrolyte additives. Finally, comparing cells with and without unwanted water contamination, it was found that the parasitic heat flow was similar or slightly higher in cells where water was intentionally removed before cycling, seemingly contradicting long-term cycling results. It is concluded that the presence of water (at the 500 ppm level) may slightly reduce parasitic reactions, but at the expense of a more resistive SEI layer.

scholarly journals Thermal structure of the deep Lopra-1/1A borehole in the Faroe Islands

2006 ◽  
Vol 9 ◽  
pp. 91-107 ◽  
Author(s):  
Niels Balling ◽  
Niels Breiner ◽  
Regin Waagstein
Keyword(s):  
Thermal Conductivity ◽  
Heat Flow ◽  
High Precision ◽  
Thermal Structure ◽  
Temperature Gradients ◽  
Depth Interval ◽  
Faroe Islands ◽  
Precision Temperature ◽  
Lapilli Tuff

Information on temperature, temperature gradients, thermal conductivity and heat flow from the c. 3.5 km deep Lopra-1/1A borehole in the Faroe Islands is presented and analysed. The upper 2450 m of the drilled sequence consists of thick tholeiitic basalt flows and the deeper parts of hyaloclastites and thin beds of basalt. Temperature data originate from high precision temperature logging a long time after drilling to a depth of 2175 m (the original Lopra-1 borehole) and from commercial temperature logs measured a short time after drilling to a depth of 3430 m (Lopra-1/1A). The high-precision temperature log determines accurately levels of inflow of groundwater to the borehole and significant thermal disturbances to a depth of c. 1250 m. Below 1300 m, no significant disturbances are seen and interval temperature gradients for large depth intervals show only small variations between 28 and 33°C/km. The mean least-squares gradient for the depth interval of 1400–3430 m is 31.4°C/ km. In clear contrast to these overall very homogeneous, large-interval, mean temperature gradients, great local variability, between gradients of 20–25°C/km and 45°C/km, was observed between about 1300 and 2175 m (maximum depth of the high-resolution temperature log). These gradient variations are interpreted to be due to thermal conductivity variations and to reflect varying secondary mineralisation and mineral alterations. A preliminary analysis of the Lopra-1/1A temperature–depth function in terms of long-term palaeoclimatic signals indicates subsurface temperatures below about 1300 m to be in equilibrium with mean surface temperatures significantly below zero during the last glacial period. A subsequent temperature increase of 12–16°C occurred at around the termination of the last glaciation. The measured temperatures (some after correction) and the thermal regime below 1300 m seem to represent conductive equilibrium conditions without significant disturbances from the effect of drilling, groundwater flow or long-term palaeoclimatic surface temperature variations. Thermal conductivity measured on samples of basalt taken from drill cores and surface outcrops in the area of the borehole shows values within a rather narrow range and a well-defined mean value for low porosity basalts of about 1.8 W/m°C , while a few samples of lapilli-tuff/tuff from the borehole gave values around 1.9 W/m°C . Lapilli-tuff and tuff seem to have higher matrix (grain) conductivity than basalt. Heat flow is estimated at 60 ± 5 mW/m2. A heat flow of this magnitude is consistent with the Faroe Islands being underlain by continental crust.

Restoration of cylinder liners for automotive tractors engines in modern conditions

2020 ◽  
pp. 122-133
Author(s):  
Vyacheslav A. Denisov ◽  
Aleksandr Yu. Kostyukov ◽  
Roman N. Zadorozhniy
Keyword(s):  
Adhesion Strength ◽  
Electrode Materials ◽  
Research Purpose ◽  
Laboratory Studies ◽  
Term Operation ◽  
Operational Load ◽  
Operational Tests ◽  
Conducting Research ◽  
Cylinder Liners

One of the most promising technologies for restoring machine parts and cylinder liners is electric spark treatment as the most versatile technology that provides high-quality restoration of worn parts with wear up to 0.5 mm. (Research purpose) The research purpose is in developing a technology for restoring various cylinder liners by means of electric spark processing, selecting optimal modes and electrode materials that allow improving the quality of repair and increasing the post-repair life of the sleeve. (Materials and methods) It was taken into account when conducting research aimed at restoring the geometric parameters of the sleeve, that the coating must have sufficient adhesion strength to the surface of the sleeve under mechanical, thermal loads and long-term operation. Laboratory studies of the adhesion strength of electric spark coatings on the separation (adhesive) and on the cut, as well as tribotechnical studies of interfaces were conducted. Authors have found by analyzing the results of operational tests of restored and new cylinder liners the prospects for using electric spark treatment of worn parts, including diesel engine liners. (Results and discussion) It was shown by laboratory studies of the adhesion strength of electric spark coatings with a 0.2 mm thick BrMKc 3-1 electrode to the working surface of cylinder liners that their separation strength (adhesive) was 20-40 megapascals, and the shear strength (cohesive) was 50-80 megapascals. It was found that this provides the required functional strength of coatings with maximum operational load. The article presents the results of comprehensive research in graphs and tables. (Conclusions) The research conducted in the CCP "Nano-Center" of the FSAC VIM and operational tests in the 2nd bus fleet of Moscow confirmed the principal possibility of effectively restoring cast iron liners (blocks) using the technology of electric spark processing.

Interpenetrating Gels as Conducting/Adhering Matrices Enabling High-Performance Silicon Anodes

2021 ◽  
Author(s):  
Tingting Xia ◽  
Chengfei Xu ◽  
Pengfei Dai ◽  
Xiaoyun Li ◽  
Riming Lin ◽  
...  
Keyword(s):  
Energy Storage ◽  
High Performance ◽  
Electrode Materials ◽  
Three Dimensional ◽  
Electrochemical Energy Storage ◽  
Active Materials ◽  
Silicon Anodes ◽  
Weak Binding ◽  
Binding Forces

Three-dimensional (3D) conductive polymers are promising conductive matrices for electrode materials toward electrochemical energy storage. However, their fragile nature and weak binding forces with active materials could not guarantee long-term...

scholarly journals One-step preparation of Cr2O3-based ink with long-term dispersion stability for inkjet applications

2021 ◽  
Author(s):  
Dongjin Xie ◽  
Qiuyi Luo ◽  
Shen Zhou ◽  
Mei Zu ◽  
Haifeng Cheng
Keyword(s):  
High Precision ◽  
Inkjet Printing ◽  
Printed Electronics ◽  
Direct Writing ◽  
Deposition Technique ◽  
Functional Material ◽  
Wide Range ◽  
One Step ◽  
Oled Display

Inkjet printing of functional material has shown a wide range of application in advertzing, OLED display, printed electronics and other specialized utilities that require high-precision, mask-free, direct-writing deposition technique. Nevertheless,...

The preparations of nanoporous carbon with multi-heteroatoms co-doping from black liquor powders for supercapacitors

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Pengfei Hao ◽  
Yanjie Yi ◽  
Youming Li ◽  
Yi Hou
Keyword(s):  
High Performance ◽  
Electrode Materials ◽  
Black Liquor ◽  
Nanoporous Carbon ◽  
Electrode System ◽  
Industrial Wastes ◽  
Co Doping ◽  
Paper Making ◽  
Symmetric Supercapacitor

Abstract A green and economically viable route without any additional activation agents and templates has been developed to synthesize biomass-derived nanoporous carbon for superior electric double-layer capacitors via direct pyrolysis of dried black liquor powders, which is the main waste in pulping and paper-making industry. The resulting carbon materials present hierarchical porosity and moderate specific surface area of 1134  m 2 g − 1 {\text{m}^{2}}\hspace{0.1667em}{\text{g}^{-1}} , as well as multi-heteroatoms co-doping such as N, S, Na and K, which exist originally in black liquor. When evaluated as electrode materials for supercapacitors in 6 M KOH aqueous electrolyte, the-prepared carbon samples deliver a significantly high gravimetric capacitance of 331  F g − 1 \text{F}\hspace{0.1667em}{\text{g}^{-1}} at 0.5  A g − 1 \text{A}\hspace{0.1667em}{\text{g}^{-1}} in a three-electrode system. Moreover, the fabricated symmetric supercapacitor also possesses a gravimetric capacitance of 211  F g − 1 \text{F}\hspace{0.1667em}{\text{g}^{-1}} at 0.5  A g − 1 \text{A}\hspace{0.1667em}{\text{g}^{-1}} , with an impressive long-term cycling stability of 92 % capacitance retention after 3000 cycles. This work explores a suitable and scalable approach for mass production of high-performance electrode materials with industrial wastes on the base of cost-efficiency and environment-friendship.

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