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wenguilong

金虫 (小有名气)

[求助] Li2TiO4化学式对吗?怎么读。可以做负极材料吗 已有2人参与

Li2TiO4化学式对吗?怎么读。可以做负极材料吗
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antibody1

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【答案】应助回帖


感谢参与,应助指数 +1
wenguilong: 金币+1, 有帮助 2014-03-06 16:30:01
目前可作为负极材料的是Li4Ti5O12,已经量产了,而Li2TiO4没听说过
2楼2014-02-18 09:46:44
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doxxod

木虫 (正式写手)

这要啥价态才行啊?
3楼2014-02-18 10:59:28
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chinagrass

铜虫 (初入文坛)

【答案】应助回帖


感谢参与,应助指数 +1
wenguilong: 金币+1, 有帮助 2014-03-06 16:29:36
有篇综述讲钛的,不记得了,有个总结
-----------
http://m.blog.sina.com.cn/s/blog_81440d6f01015y2z.html#page=2

相比现在通用的石墨,氧化钛作为锂电池负极材料有明显的优点也有明显的缺点。

下面比较了不同类型的氧化钛作为负极材料的特点。
-----------------------------------------

Ti-O system in General
As compared to graphite, which is commercially used as anode in lithium ion batteries, the Ti-O system has the advantage of high rate and absence of solid electrolyte interphase (SEI) formation, but suffers from its low conductivity.
In the following discussion, the maximum theoretical capacity has to be distinguished from practical capacity. All TiO2 have the same max theoretical capacity: LiTiO2, that is, 1 Li per Ti or 336 mAhg-1. However, this theoretical capacity is limited by several parameters such as phase, particle size, etc. B-TiO2 shows the higher practical capacity for similar conditions since Li-ion diffusion is higher.

Beta-TiO2 (TiO2-B)
-  Higher capacity than any other Li-Ti-O system or TiO2 polymorphs
-  Monoclinic, space group C2/m, parallel channel along [010], corner-sharing TiO6 octahedral
-  Metastable phase
-  Favour insertion and diffusion of Li along the channel
-  Performance strongly depending on microstructure
-  Synthesis: hydrothermal, sol-gel, solvothermal methods
-  Problem: rate capacity due to low electron conductivity, can possibly improved by doping

Rutile TiO2
-  Uptake only <0.1 Li atom per TiO2 at room temperature
-  The main limitation is the 1-dimention Li-ion diffusion (channel diffusion). If the channel is blocked in one point, the inner part will be lost (hinder the access of Li-ion to the bulk).
-  A practical capacity for microparticle is 0.1 Li per Ti, but this can be improved by decreasing the particle size or increasing temperature.
-  Can be improved to 0.7 Li atom (235 mAh/g), reversible 0.55 Li (185 mAh/g)

Anatase TiO2
-  Uptake 0.5 Li atom per TiO2, further Li-ion (above 0.5 Li) can be inserted only in small nanoparticles or mesopores.
-  phase transformation due to Li intercalation (from tetragonal to orthorhombic)
-  200 mAh/g, 1.7 V
-  Problem: low conductivity
-  Solutions: decrease particle size, carbon composite, carbon coating

Li4Ti5O12
-  spinel structure, band gap 2 eV
-  most commonly used so far
-  3 Li insertion: Li4Ti5O12 + 3Li àLi7Ti5O12
-  3/5 Li atoms per Ti (maximum theoretical capacity of 0.6 Li).
-  two phase intercalation mechanism
-  0.2% volume change, lattice from 0.83595 nm to 0.83538 nm,
-  175 mAh/g, 1.55 V
-  Problem: low conductivity
-  Solutions: decrease particle size, carbon composite, carbon coating

Li2Ti3O7
-  ramsdellite-type structure
-  Fast Li ion conductor
-  One phase solid solution intercalation
-  2.28 Li atom insertion
-  2% volume change
-  235 mAh/g
-  Ion doping problem, poor cycling performance

Li2Ti6O13
-  Monoclinic C2/m space group
-  good Li ion conductor
-  >200 mAh/g, 1.5 V
-  poor cycling performance, significant loss of capacity in the first few cycles
4楼2014-02-18 17:07:15
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