Effect of heat treatment time on cycle performance of LiMn2O4 with “Nano Inclusion” for lithium ion batteries

RSC Advances ◽  
2015 ◽  
Vol 5 (53) ◽  
pp. 42455-42460 ◽  
Author(s):  
Shogo Esaki ◽  
Motoaki Nishijima ◽  
Shigeomi Takai ◽  
Takeshi Yao

The cycle performance of LiMn2O4 with “Nano Inclusions” is higher than that of LiMn2O4 without “Nano Inclusions” and the discharge capacity of LiMn2O4 with “Nano Inclusions” heat-treated for 4 h surpassed that of LiMn2O4 without it at over 31 cycles.

Author(s):  
Shouyu Zhang ◽  
Junfu Lu ◽  
Jianmin Zhang ◽  
Qing Liu ◽  
Guangxi Yue

The effect of heat treatment on the reactivity and crystallinity of char prepared from the vitrinite of two coals (YX, JJ) was investigated by using XRD and TGA in this paper. The results from TGA show that the reactivity of the chars from YXV and JJV decreases with the increase of heat treatment temperature. The reactivity of YXV char decreases quickly and significantly as heat treatment time increases. However, after heat treatment time of 60 min, it decreases slowly. The effect of heat treatment time on the reactivity of JJV char is small. The results from XRD show that the crystallinity of coal-char is determined by the intensity of heat treatment. When heat treatment time is more than 60 minutes, the turbostratic crystallite of YXV char prepared under 900°C changes remarkably and becomes more orderly. The aromatic layer stacking heights (Lc) of YXV Char when heat treated above 900°C increased with the increase of heat treatment time. The effect of heat treat time on Lc of JJV char is small, but under heat treatment temperature of 1200°C, the crystalline of JJV char grows distinctly. There is a good parallel relationship between the crystalline growth and deactivation of the chars. It can be concluded that the growth of the crystalline is the main reason for the deactivation of coal-char.


2012 ◽  
Vol 468-471 ◽  
pp. 1118-1122
Author(s):  
Yan Jun Li ◽  
Lan Xing Du ◽  
Gou Ying Hu ◽  
Xing Xia Ma

To enhance decay resistance, the effect of heat treatment and the variation of chemical composition on Chinese Fir and Pine were investigated in this study — heat treatment temperature was 170°C, 190°C and 210°C, respectively, heat treatment time was 2, 3 and 4hours, respectively. Both of them were subsequently exposed to white-rot fungus and brown-rot fungus. The results showed that:(1) With the increasing of the heat treatment, decay resistance of Chinese Fir and Pine were improved, anti-corrosion of Pine after being heat treated at 190°C which were exposed to write-rot fungus can reach I, anti-corrosion of Chinese Fir after being heat treated at 170°C treated which were exposed to brown-rot fungus could reach I yet, After being heat treated at 210°C for 3 hours , the Chinese fir samples had no measurable weight loss when exposed to the write-rot fungus.(2) There was no remarkable influence on both Chinese Fir and Pine by heat treatment time.(3) The moisture content of Chinese Fir and Pine were lower than the moisture content that the rot fungus need, macromolecule chains such as cellulose and hemicellulose broke down, their contents decreased, and the hemicellulose decomposed into acetic acid, they prevented the growth of rot fungus.


2006 ◽  
Vol 317-318 ◽  
pp. 317-322 ◽  
Author(s):  
J.Q. Zhang ◽  
Atsunori Matsuda ◽  
Hiroyuki Muto ◽  
Mototsugu Sakai

Methylsilsesquioxane films were formed on glass substrates by dropping a sol prepared from methyltriethoxysilane and then heat-treated in an oven. Nanoindentation test was performed to assess the elastoplastic properties of the films, including the relative residual depth ξr, Meyer hardness HM, work-of-indentation WI and the elastic modulus E’. The values of ξr, HM and WI were obtained by a Berkovich indenter and E’ was determined by a spherical indenter on the basis of Hertz elastic theory. ξr decreased with the increase in the heat treatment time, whereas HM , WI and E’ significantly increased with the time. The changes in the mechanical properties with the heat treatment time well reflected the evolution of the Si-O-Si network structure in methylsilsequioxane film.


2013 ◽  
Vol 773-774 ◽  
pp. 785-794
Author(s):  
Amir Mahmoudi ◽  
Mohammad Esmailian ◽  
Seyed Eshagh Aghamiri

In this investigation, AISI321 steel was solution - stabilizing post heat treated in various temperatures and times after SMAW welding. Results show, increasing of temperature in solution and stabilizing heat treatment, raise sensitization; in addition, by increasing of the solution heat treatment time, sensitization enhances. However, increasing the time of stabilizing heat treatment creates less chrome carbides, so the sensitization decreases. These heat treatments reduce the amount of delta ferrite and change its morphology from narrow and acicular shape to discontinues and separate globular particles. Moreover, more carbide and carbonitrid of Ti and Nb are also created.


1999 ◽  
Vol 575 ◽  
Author(s):  
S. Fujitani ◽  
H. Fujimoto ◽  
T. Nohma ◽  
K. Nishio

ABSTRACTLiNi1−xCoxO2(x=0.2, 0.3, 0.4) was synthesized through a sintering process from two different types of source materials of nickel and cobalt, namely each respective hydroxide and oxide, and composite hydroxide. Influence of the difference on charge-discharge characteristics, crystal structure and distribution of the metal elements was investigated.The composite hydroxides formulated in Ni1−xCox(OH)2 as the source material brought better homogenized composite lithiated nickel based metal oxides exhibiting the larger specific discharge capacity. Further modification of LiNi0.6Co0.4)2 by manganese through sintering from the composite hydroxide including manganese brought a good charge-discharge cycle performance as well as a high discharge capacity of 160mAh/g level.A cylindrical test cell of 18mm in diameter and 65mm in height using the LiNi0.6Co0.3Mn0.1O2 exhibited discharge capacity of 1700mAh which is larger than that using LiCoO2, and also exhibited a competitive charge-discharge cycle performance to commercialized lithium ion batteries.


2015 ◽  
Vol 3 (7) ◽  
pp. 3547-3558 ◽  
Author(s):  
Huanqiao Song ◽  
Yaguang Liu ◽  
Cuiping Zhang ◽  
Chaofeng Liu ◽  
Guozhong Cao

A new Mo-doped LiV3O8 nanorod-assembled nanosheet was prepared by a simple hydrothermal method and subsequent calcination. Its unique structure demonstrates a maximum discharge capacity of 269 mAh g−1 at 300 mA g−1 within 4.0-2.0 V, and excellent rate and cycle performance for Li-ion batteries.


2020 ◽  
Vol 59 (1) ◽  
pp. 477-487 ◽  
Author(s):  
Zhuang Liu ◽  
Haiyang Fu ◽  
Bo Gao ◽  
Yixuan Wang ◽  
Kui Li ◽  
...  

AbstractThis paper studies in-situ synthesis of Fe2O3/reduced graphene oxide (rGO) anode materials by different hydrothermal process.Scanning Electron Microscopy (SEM) analysis has found that different processes can control the morphology of graphene and Fe2O3. The morphologies of Fe2O3 prepared by the hydrothermal in-situ and oleic acid-assisted hydrothermal in-situ methods are mainly composed of fine spheres, while PVP assists The thermal in-situ law presents porous ellipsoids. Graphene exhibits typical folds and small lumps. X-ray diffraction analysis (XRD) analysis results show that Fe2O3/reduced graphene oxide (rGO) is generated in different ways. Also, the material has good crystallinity, and the crystal form of the iron oxide has not been changed after adding GO. It has been reduced, and a characteristic peak appears around 25°, indicating that a large amount of reduced graphene exists. The results of the electrochemical performance tests have found that the active materials prepared in different processes have different effects on the cycle performance of lithium ion batteries. By comprehensive comparison for these three processes, the electro-chemical performance of the Fe2O3/rGO prepared by the oleic acid-assisted hydrothermal method is best.


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