本文關(guān)鍵詞： 鋰離子電池 二氧化鈦 混晶 納米管 多巴胺　出處：《北京化工大學(xué)》2016年碩士論文　論文類型：學(xué)位論文

【摘要】：近年來,隨著環(huán)境污染問題逐漸得到了大眾關(guān)注,鋰離子電池作為一種清潔的汽車動(dòng)力能源越來越受到重視,由此對(duì)鋰離子電池的能量密度和安全性能提出了更高的要求。此外,隨著手機(jī)等電子產(chǎn)品屏幕越來越大,耗電越來越快,鋰離子電池的容量和倍率性能也成了衡量鋰離子電池品質(zhì)的關(guān)鍵。二氧化鈦(TiO2)具有廉價(jià)、環(huán)保的特點(diǎn),其納米材料作為鋰離子電池負(fù)極具有理論容量高、安全性能好、能量密度高、充放電平臺(tái)高、可快速充放電等優(yōu)點(diǎn),是十分有前景的鋰離子電池負(fù)極材料。其中的一維納米TiO2由于具有兩方向的鋰離子傳輸通道,可以通過很大的電流快速充放電,能夠滿足人們對(duì)電動(dòng)交通工具和數(shù)碼產(chǎn)品快速充放電的需要。此外一維納米TiO2采用水熱法制備,操作簡便,具有商用推廣的條件。本文采用水熱法制備一維納米TiO2,探究水熱溫度、燒結(jié)溫度對(duì)一維納米TiO2的形貌和電化學(xué)性能的影響,得到兩種TiO2-B晶型和銳鈦礦晶型同時(shí)存在的TiO2納米管(TiO2-400和TiO2-500),這兩種混晶TiO2納米管均具有較高的容量、良好的循環(huán)性能和優(yōu)異的倍率性能。為進(jìn)一步提高混晶TiO2納米管的性能,嘗試采用石墨烯和多巴胺包覆對(duì)混晶TiO2納米管進(jìn)行碳包覆,其中多巴胺包覆6h后700℃碳化所得的材料具有TiO2-B晶型和銳鈦礦晶型混合的管型結(jié)構(gòu),以及合適厚度(-2nm)的碳包覆層,從而同時(shí)具有高容量、高倍率性能及高循環(huán)穩(wěn)定性的優(yōu)點(diǎn)。該材料以200mA·g-1電流密度500次循環(huán)后容量保持在177.5mAh·g-1,大電流密度2000mA·g-1下容量為141.2mAh·9-1,600次大電流密度循環(huán)后(2000mA·g-1),容量仍然維持在140.5mAh·g-1。
[Abstract]:In recent years, with the environmental pollution problem gradually getting the attention of the public, lithium ion battery as a kind of clean automobile power energy has been paid more and more attention. As a result, the energy density and safety performance of Li-ion batteries are required higher and higher. In addition, as the screen of electronic products such as mobile phones becomes larger and larger, the power consumption becomes faster and faster. The capacity and performance of lithium-ion batteries have also become the key to evaluate the quality of lithium-ion batteries. Titanium dioxide (TIO _ 2) has the characteristics of low cost and environmental protection. As a negative electrode of lithium ion battery, nano-material has the advantages of high theoretical capacity, good safety performance, high energy density, high charging and discharging platform, rapid charging and discharging, and so on. It is a promising cathode material for lithium-ion batteries, in which one-dimensional nanocrystalline TiO2 can charge and discharge rapidly through a large current due to its two-direction lithium ion transmission channel. It can meet the need of rapid charge and discharge of electric vehicles and digital products. In addition, one-dimensional nanocrystalline TiO2 is prepared by hydrothermal method, which is easy to operate. In this paper, one-dimensional nano-TiO _ 2 was prepared by hydrothermal method. The effects of hydrothermal temperature and sintering temperature on the morphology and electrochemical properties of one-dimensional nano-TiO _ 2 were investigated. Two kinds of TiO2 nanotubes, TiO2-400 and TiO2-500, with both TiO2-B and anatase crystal forms were obtained. These two kinds of mixed-crystal TiO2 nanotubes have high capacity, good cycling performance and excellent rate performance, in order to further improve the properties of mixed-crystal TiO2 nanotubes. Carbon coating of mixed crystal TiO2 nanotubes with graphene and dopamine was attempted. The materials obtained by carbonization at 700 鈩，

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