scholarly journals The Composition of Oxygen Functionals Groups at the Surface of Carbon-Based Graphitic Anode

2021 ◽  
Author(s):  
Nadia Intan ◽  
Jim Pfaendtner
Keyword(s):  
Functional Groups ◽  
Solid Electrolyte Interphase ◽  
Lithium Ion ◽  
Operating Conditions ◽  
Carbonyl Groups ◽  
Basal Surface ◽  
Oxygen Functional Groups ◽  
Ketonic Group ◽  
The Stability

In lithium-ion batteries (LIBs), the quality of a solid electrolyte interphase (SEI) that forms at the electrode/electrolyte interface substantially affects the stability and lifetime of the devices. One of the major determinants of the morphology and properties of SEI is the surface structure and composition of the graphitic anode used. The presence of oxygenated surface groups at the graphitic anode facilitates the formation of SEI at the interface that stabilizes LIBs. A series of DFT calculations reveal that at typical operating conditions (temperature, pH) of LIBs, the (1120) edge facet of graphite anode will be fully oxygenated, while the basal sites remain unsaturated. The oxygen functional groups at the edge sites are comprised of mostly hydroxyl and ketonic groups, with carboxyl and carbonyl groups are present in small amounts. Furthermore, we observe transformation of carbonyl group into ketonic group in the presence of empty surface carbon sites, which further stabilize the graphite surface. Meanwhile, carboxyl groups are more stable when all surface sites within a carboxyl layer are all populated. On the contrary to the edge plane, a small amount of oxygen functional groups may be forced to adsorb on the basal surface upon application of an external potential.

scholarly journals Assessment of vehicle brake control functional stability

2021 ◽  
Vol 12 (2) ◽  
pp. 33-44
Author(s):  
Volodymyr Volkov ◽  
◽  
Igor Gritsuk ◽  
Tetiana Volkova ◽  
Volodymyr Kuzhel ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Control Method ◽  
Operating Conditions ◽  
National Standards ◽  
Passenger Vehicles ◽  
The Difference ◽  
Braking Control ◽  
The Stability ◽  
Friction Surfaces

The article is devoted to the study of the influence of the brake control elements of passenger vehicles on the stability of their braking properties. The analysis of the influence of uneven braking forces on the wheels of one axle of vehicles on the deviation of the distribution of braking forces between the axles from its calculated value is carried out. When assessing the error in regulating the distribution of braking forces between the axles of vehicles, three components were taken into account: the theoretical error due to the imperfection of the selected control method (the difference between the actual calculated control characteristic from the ideal), the error created due to the instability of the ratio of the braking forces on the front and rear wheels, an additional error caused by the unevenness of the braking forces on the wheels of individual axles, since the fulfillment of the most stringent requirements of international and national standards for the efficiency of braking of vehicles and is inextricably linked with the need to increase the energy consumption of brake mechanisms. The energy consumption of braking mechanisms is understood as the ability of the latter to dissipate the greatest amount of energy of the braking machine without reducing the braking efficiency indicators to the minimum permissible level. Excessive heating of the braking mechanisms leads to a decrease in the friction coefficient μ of the friction surfaces and increased wear of the friction linings, and the brakes are the most unstable element of the braking control, which ensures the absorption and dissipation of the vehicle's energy during braking. The instability of the braking torques on the front and rear wheels, caused by a change in the coefficients of friction of friction pairs, leads not only to a change in the distribution of braking forces between the axles and individual wheels, but also to a decrease in the braking efficiency of vehicles under operating conditions. A method is proposed that makes it possible to assess the quality of regulation of the distribution of braking forces between the axles of a car, taking into account the instability of the braking forces on the wheels.

scholarly journals Room temperature production of graphene oxide with thermally labile oxygen functional groups for improved lithium ion battery fabrication and performance

2019 ◽  
Vol 7 (16) ◽  
pp. 9646-9655 ◽  
Author(s):  
Jiadong Qin ◽  
Yubai Zhang ◽  
Sean E. Lowe ◽  
Lixue Jiang ◽  
Han Yeu Ling ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Lithium Ion Battery ◽  
Functional Groups ◽  
Room Temperature ◽  
Synthesis Method ◽  
Lithium Ion ◽  
Temperature Synthesis ◽  
Room Temperature Synthesis ◽  
Oxygen Functional Groups ◽  
And Performance

We report a room-temperature synthesis method to produce graphene oxide with thermally-labile oxygen functional groups.

Decomposition of the fluoroethylene carbonate additive and the glue effect of lithium fluoride products for the solid electrolyte interphase: an ab initio study

2016 ◽  
Vol 18 (12) ◽  
pp. 8643-8653 ◽  
Author(s):  
Yukihiro Okuno ◽  
Keisuke Ushirogata ◽  
Keitaro Sodeyama ◽  
Yoshitaka Tateyama
Keyword(s):  
Solid Electrolyte ◽  
Lithium Ion Batteries ◽  
Electrolyte Solution ◽  
Lithium Fluoride ◽  
Solid Electrolyte Interphase ◽  
Lithium Ion ◽  
Ab Initio Study ◽  
Fluoroethylene Carbonate ◽  
The Stability ◽  
Fluoroethylene Carbonate Additive

Additives in the electrolyte solution of lithium-ion batteries (LIBs) have a large impact on the performance of the solid electrolyte interphase (SEI) that forms on the anode and is a key to the stability and durability of LIBs.

scholarly journals High transference number enabled by sulfated zirconia superacid for lithium metal batteries with carbonate electrolytes

2020 ◽  
Author(s):  
Sang-Gil Woo ◽  
Eun-Kyoung Hwang ◽  
Hee-Kook Kang ◽  
Haeun Lee ◽  
Je-Nam Lee ◽  
...  
Keyword(s):  
Sulfated Zirconia ◽  
Solid Electrolyte Interphase ◽  
Lithium Ion ◽  
Transference Number ◽  
Operating Conditions ◽  
Interfacial Instability ◽  
Lithium Metal ◽  
Lithium Metal Batteries ◽  
Lithium Dendrites ◽  
Battery Technology

Abstract The prospect of increasing the energy density has promoted research on lithium metal batteries. Yet, avoiding the uncontrolled growth of lithium dendrites and the resulting interfacial instability to ensure the practical viability of the given battery technology remains a considerable challenge. Here, we report coating the separator with sulfated zirconia superacid to achieve a high lithium ion transference number of 0.92 and compelling cycle life when a full-cell paired with a LiNi0.82Co0.07Mn0.11O2 cathode was tested in a carbonate electrolyte under practical operating conditions. The exceptionally high transference number is attributed to strengthened binding of the PF6− anion of the lithium salt with the superacid. Furthermore, a trace amount of water bound to the superacid reacts with PF6− to induce a mechanically stable solid-electrolyte-interphase (SEI) layer rich in LixPOyFz. This study demonstrates the beneficial effect of the superacid on emerging post-lithium-ion batteries by immobilizing the anion of the salt as well as modifying the SEI composition.

How functional groups influence the ROS generation and cytotoxicity of graphene quantum dots

2017 ◽  
Vol 53 (76) ◽  
pp. 10588-10591 ◽  
Author(s):  
Ya Zhou ◽  
Hanjun Sun ◽  
Faming Wang ◽  
Jinsong Ren ◽  
Xiaogang Qu
Keyword(s):  
Quantum Dots ◽  
Functional Groups ◽  
Graphene Quantum Dots ◽  
Ros Generation ◽  
Hydroxyl Groups ◽  
Carbonyl Groups ◽  
Oxygen Functional Groups

Herein we selectively deactivate the ketonic carbonyl, carboxylic, or hydroxyl groups on GQDs and compare their ROS generation ability. The ROS generation ability of GQDs is closely related to these oxygen functional groups, especially for the ketonic carbonyl groups.

Fluoroethylene Carbonate Enabling a Robust LiF-rich Solid Electrolyte Interphase to Enhance the Stability of the MoS2 Anode for Lithium-Ion Storage

2018 ◽  
Vol 130 (14) ◽  
pp. 3718-3722 ◽  
Author(s):  
Zhiqiang Zhu ◽  
Yuxin Tang ◽  
Zhisheng Lv ◽  
Jiaqi Wei ◽  
Yanyan Zhang ◽  
...  
Keyword(s):  
Solid Electrolyte ◽  
Solid Electrolyte Interphase ◽  
Lithium Ion ◽  
Ion Storage ◽  
Fluoroethylene Carbonate ◽  
The Stability

Adhesion and Surface Layers on Silicon Anodes Suppress Formation of c-Li3.75Si and Solid Electrolyte Interphase

2019 ◽  
Author(s):  
Hezhen Xie ◽  
Sayed Youssef Sayed ◽  
W. Peter Kalisvaart ◽  
Simon Jakob Schaper ◽  
Peter Müller-Buschbaum ◽  
...  
Keyword(s):  
Solid Electrolyte ◽  
Photoelectron Spectroscopy ◽  
Solid Electrolyte Interphase ◽  
Copper Substrate ◽  
Lithium Ion ◽  
Adhesion Layer ◽  
Capacity Retention ◽  
Silicon Anodes ◽  
Capacity Degradation ◽  
The Stability

<div>The formation of c-Li3.75Si is known to be detrimental to silicon anodes in lithium-ion batteries. To suppress the formation of this crystalline phase and improve the electrochemical performance of Sibased anodes, three approaches were amalgamated: addition of a nickel adhesion sublayer, alloying of the silicon with titanium, and the addition of either carbon or TiO2 as a capping layer. The silicon-based films were analyzed by a suite of methods, including scanning electron microscopy (SEM) and a variety of electrochemical methods, as well as X-ray photoelectron spectroscopy (XPS) to provide insights into the composition of the resulting solid electrolyte interphase (SEI). A nickel adhesion layer decreased the extent of delamination of the silicon from the underlying copper substrate, compared to Si deposited directly on Cu, which resulted in less capacity loss. Alloying of silicon with titanium (85% silicon, 15% titanium) further increased the stability. Finally, capping these multilayer electrodes with either a thin 10 nm layer of carbon or TiO2 resulted in the best electrode behavior, and lowest cumulative relative irreversible capacity. TiO2 is slightly more effective in enhancing the capacity retention, most likely due to differences in the resulting solid electrolyte interphase (SEI). The combination of an adhesion layer, alloying, and surface coatings shows a cumulative suppression of the formation of c-Li3.75Si and SEI, resulting in the greatest improvement of capacity retention when all three are incorporated together. However, these strategies appear to only delay the onset of the c-Li3.75Si phase; eventually, the c-Li3.75Si phase will form, and at that point, the rate of capacity degradation of all the electrodes becomes similar.</div>

Effect of Fluorine-Containing Additive on the Electrochemical Properties of Silicon Anode for Lithium-Ion Batteries

2019 ◽  
Vol 944 ◽  
pp. 699-704 ◽  
Author(s):  
Jing Wang ◽  
Xiao Hang Yang ◽  
Yue Feng Su ◽  
Shi Chen ◽  
Feng Wu
Keyword(s):  
Lithium Ion Batteries ◽  
Coulombic Efficiency ◽  
Solid Electrolyte Interphase ◽  
Specific Capacity ◽  
Lithium Ion ◽  
Silicon Anode ◽  
Cycle Stability ◽  
Promising Candidate ◽  
Sem Images ◽  
The Stability

Silicon anode is a promising candidate as an alternative to the conventional graphitic anode in lithium-ion batteries. In this work, silicon anode is modified by NH4F using a facile method in air. The concentration of NH4F on the electrochemical performance is systematically checked. The 5wt%NH4F-modified silicon anode exhibits enhanced cycle and rate performances, the first discharge specific capacity is 3958 mAh·g-1 with 86.45% as the coulombic efficiency at 0.4A·g-1. The capacity can maintain at 703.3 mAh·g-1 after 50 cycles, exhibiting a much better cycle stability than pristine silicon anode (329.9 mAh·g-1 after 50 cycles). SEM images confirm that NH4F can alleviate the volume expansion of silicon since LiF can be generated at the surface which is beneficial to the stability of solid-electrolyte interphase (SEI).

Adhesion and Surface Layers on Silicon Anodes Suppress Formation of c-Li3.75Si and Solid Electrolyte Interphase

2019 ◽  
Author(s):  
Hezhen Xie ◽  
Sayed Youssef Sayed ◽  
W. Peter Kalisvaart ◽  
Simon Jakob Schaper ◽  
Peter Müller-Buschbaum ◽  
...  
Keyword(s):  
Solid Electrolyte ◽  
Photoelectron Spectroscopy ◽  
Solid Electrolyte Interphase ◽  
Copper Substrate ◽  
Lithium Ion ◽  
Adhesion Layer ◽  
Capacity Retention ◽  
Silicon Anodes ◽  
Capacity Degradation ◽  
The Stability

<div>The formation of c-Li3.75Si is known to be detrimental to silicon anodes in lithium-ion batteries. To suppress the formation of this crystalline phase and improve the electrochemical performance of Sibased anodes, three approaches were amalgamated: addition of a nickel adhesion sublayer, alloying of the silicon with titanium, and the addition of either carbon or TiO2 as a capping layer. The silicon-based films were analyzed by a suite of methods, including scanning electron microscopy (SEM) and a variety of electrochemical methods, as well as X-ray photoelectron spectroscopy (XPS) to provide insights into the composition of the resulting solid electrolyte interphase (SEI). A nickel adhesion layer decreased the extent of delamination of the silicon from the underlying copper substrate, compared to Si deposited directly on Cu, which resulted in less capacity loss. Alloying of silicon with titanium (85% silicon, 15% titanium) further increased the stability. Finally, capping these multilayer electrodes with either a thin 10 nm layer of carbon or TiO2 resulted in the best electrode behavior, and lowest cumulative relative irreversible capacity. TiO2 is slightly more effective in enhancing the capacity retention, most likely due to differences in the resulting solid electrolyte interphase (SEI). The combination of an adhesion layer, alloying, and surface coatings shows a cumulative suppression of the formation of c-Li3.75Si and SEI, resulting in the greatest improvement of capacity retention when all three are incorporated together. However, these strategies appear to only delay the onset of the c-Li3.75Si phase; eventually, the c-Li3.75Si phase will form, and at that point, the rate of capacity degradation of all the electrodes becomes similar.</div>

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