發(fā)布時間：2018-06-03 17:40

  本文選題：鋰離子電池 + 尖晶石型錳酸鋰��； 參考：《齊魯工業(yè)大學》2015年碩士論文

【摘要】：隨著電子設備行業(yè)的迅猛發(fā)展以及能源枯竭和環(huán)境污染等問題的日趨明顯,人們對化學電源的要求越來越高。尖晶石型結(jié)構的錳酸鋰(LiMn2O4)因其豐富的資源來源、廉價的成本、無污染等優(yōu)勢,是近期發(fā)展現(xiàn)狀下鋰離子行業(yè)最有發(fā)展前景的正極材料。尖晶石型結(jié)構的錳酸鋰(LiMn2O4)因為諸多因素的影響,電池的性能還不是很好,因此改善其性能成為研究熱點。以廉價的碳酸鋰(Li2CO3)和二氧化錳(MnO2)為原料,采用高溫分段燒結(jié)相結(jié)合的方法,合成純相尖晶石型結(jié)構的錳酸鋰(LiMn2O4)正極材料。本文通過差熱熱重分析(TG-DSC)實驗,確定純相尖晶石型結(jié)構的錳酸鋰(LiMn2O4)的燒結(jié)溫度；通過X射線衍射(XRD)和掃描電鏡(SEM)測試,表征純相尖晶石型結(jié)構的錳酸鋰(LiMn2O4)的結(jié)構和微觀形貌；通過充放電測試實驗,研究合成的純相尖晶石型結(jié)構的錳酸鋰(LiMn2O4)的綜合電化學性能。本文主要是通過以下方法對錳酸鋰進行改性研究：(1)改進合成方法(2)體相摻雜改性(3)材料表面包覆改性。在改進合成方法研究方向,主要是采取對原材料進行球磨的方法且首次研究球磨對錳酸鋰(111)晶面的影響。球磨后合成的尖晶石型結(jié)構的錳酸鋰(LiMn2O4)的性能更為優(yōu)異,在球磨時間為6小時時達到最佳值(在0.5C倍率下首次充放電為129.3 mAh/g,30循環(huán)后容量保持率為94.95%),且研究表明球磨后可以改變錳酸鋰(111)晶面的大小從而影響錳酸鋰的電化學性能。在體相摻雜改性方向,研究Ni、Co、Al、F等陰陽離子單獨摻雜對錳酸鋰電化學性能的影響以及A1、F陰陽離子復合摻雜對錳酸鋰電化學性能的影響。研究表明,Ni、Co、Al等陽離子單獨摻雜改性錳酸鋰,首次充放電都是減小的,但是循環(huán)保持率明顯提高；F離子單獨摻雜改性錳酸鋰,首次充放電是增加的且循環(huán)保持率較好；A1、F陰陽離子復合摻雜改性錳酸鋰不但可以保持首次充放電的大小且可以提高其循環(huán)保持率。在材料表面包覆改性方向,研究硅溶膠表面包裹改性對錳酸鋰電化學性能的影響。研究表明,硅溶膠表面包裹改性錳酸鋰后,在錳酸鋰的表面形成了一層包裹相,隨著硅溶膠加入量的增加,樣品(LiMn2O4)的放電比容量是減小的而容量保持率是先增加后減小,當硅溶膠加入量小于2.0wt%時,樣品(LiMn2O4)的容量保持率由92.241%增加到了94.068%,但當硅溶膠加入量大于2.0wt%時,樣品的容量保持率開始減小
[Abstract]:With the rapid development of electronic equipment industry and the increasingly obvious problems such as energy depletion and environmental pollution, people are demanding more and more chemical power supply. Spinel LiMn2O4 is the most promising cathode material in lithium ion industry due to its abundant resource sources, low cost and no pollution. Spinel LiMn2O4) because of the influence of many factors, the performance of the battery is not very good, so improving its performance has become a research hotspot. LiMn2O4) cathode material with pure spinel structure was synthesized from cheap lithium carbonate (Li _ 2CO _ 3) and manganese dioxide (mn _ 2O _ 2). The sintering temperature of pure spinel LiMn2O4 (LiMn2O4) was determined by differential thermogravimetric analysis (TG-DSCC), and the structure and microstructure of pure spinel LiMn2O4 were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The electrochemical properties of pure spinel LiMn2O4 were studied by charge-discharge test. In this paper, the modification of lithium manganese oxide by the following methods is studied. In the research direction of improving the synthesis method, we mainly adopt the method of ball milling of raw materials and study the effect of ball milling on the crystal plane of lithium manganese oxide (111) for the first time. The spinel structure LiMn2O4) prepared by ball milling has better properties. When the milling time is 6 hours, the optimum value (the first charge and discharge at 0.5C rate is 129.3 mg 路g / g ~ (30) cycle capacity retention rate is 94.95%, and the study shows that the size of crystal plane can be changed after ball milling, thus affecting the electrochemical performance of lithium manganese oxide. In the direction of bulk doping modification, the effect of the single doping of anionic and anion ions, such as NiCoCoAlF, on the electrochemical properties of lithium manganese oxide and the influence of the composite doping of A _ (1) O _ (F) ions on the electrochemical properties of lithium manganese oxide were studied. The results show that the initial charge and discharge rate of modified lithium manganate is decreased, but the cyclic retention rate of F ion is obviously increased. The first charge / discharge rate is increased and the cyclic retention rate is better. The modified lithium manganese oxide doped with anion and anion can not only keep the size of the first charge and discharge but also improve the recycling retention rate. The effect of surface encapsulation modification of silica sol on the electrochemical properties of lithium manganese oxide was studied. The results show that a layer of encapsulation phase is formed on the surface of lithium manganese oxide coated with silica sol. With the increase of silica sol content, the discharge specific capacity of LiMn2O4) decreases and the capacity retention rate increases first and then decreases. When the amount of silica sol was less than 2.0 wt%, the capacity retention rate of the sample LiMn2O4 increased from 92.241% to 94.068%, but when the amount of silica sol was more than 2.0 wt%, the capacity retention rate of the sample began to decrease.
【學位授予單位】：齊魯工業(yè)大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TM912

【參考文獻】

相關期刊論文 前1條

1 李偉善,羅穗蓮,呂東升,邱仕洲;鋰離子電池正極活性物質(zhì)研究[J];電池工業(yè);2000年06期

，

本文編號：1973632