本文選題：鋰離子電池 + 燃燒法　； 參考：《蘭州理工大學(xué)》2016年碩士論文

【摘要】：隨著鋰離子電池的快速發(fā)展,低成本的電極材料引起了人們的更多關(guān)注,尖晶石LiMn_2O_4具有很強的競爭力,由于高安全性、錳資源豐富、價格低廉、環(huán)境友好等特點,被認為是最具潛力的鋰離子電池正極材料之一。近些年來,已經(jīng)被廣泛的應(yīng)用到電動汽車上。但是,由于LiMn_2O_4材料Mn~(3+)溶解導(dǎo)致的楊-泰勒效應(yīng)以及結(jié)晶度降低,導(dǎo)致材料的容量衰減嚴重。大量研究發(fā)現(xiàn),LiMn_2O_4的電化學(xué)性能與合成工藝、材料的粒徑大小,微觀形貌等有很大關(guān)系,本文主要從減少材料的粒徑尺寸、聚丙烯酸鋰表面包覆和功能粘接劑三個方面改進LiMn_2O_4材料的電化學(xué)性能。通過電化學(xué)測試以及XRD、SEM和TEM等表征方法,研究了LiMn_2O_4材料的結(jié)構(gòu)、形貌和電化學(xué)性能。主要研究內(nèi)容包括:(1)通過碳納米管輔助溶液燃燒法,以LiNO_3,50%Mn(NO_3)_2溶液為原料,碳納米管作燃料,成功合成了超細的LiMn_2O_4材料,研究了CNTs對LiMn_2O_4材料的結(jié)構(gòu)以及電化學(xué)性能的影響,倍率性能測試表明,CNTs的添加量對LiMn_2O_4材料的電化學(xué)表現(xiàn)有很大的影響。選擇添加7%的CNTs作燃料時合成的LiMn_2O_4材料(C7%-LMO)具有高的充放電比容量。通過XRD分析表明,樣品C7%-LMO具有最低的晶格畸變度。SEM分析表明,C7%-LMO的晶粒尺寸為100 nm,具有最小的晶粒尺寸。樣品C7%-LMO這些獨特的微觀形貌特征保證了其具有最高的放電比容量,該樣品在0.2C時第二次放電比容量為115.1 mAh·g~(-1),且在10C時仍然能夠達到77 mAh·g~(-1),在1C倍率下經(jīng)過100次循環(huán),其循環(huán)效率為94.8%。減少晶粒大小能夠縮短鋰離子在電極材料中的遷移距離,因此,C7%-LMO表現(xiàn)出最佳的電化學(xué)性能。(2)通過溶液燃燒法,以LiNO_3,Mn(CH3COO)2·4H2O和50%Mn(NO_3)_2溶液為原料,成功合成了尖晶石LiMn_2O_4材料。采用PAALi對LiMn_2O_4進行包覆,研究了不同PAALi包覆量對材料結(jié)構(gòu)和性能的影響,通過XRD、TEM和ICP-OES等表征及電化學(xué)性能測試分析,結(jié)果表明采用PAALi包覆能夠阻止LiMn_2O_4電極材料中錳的溶解,從而提高LiMn_2O_4材料在電解液中的穩(wěn)定性,當PAALi的包覆量為2%時,包覆材料(標記為LMO@2%PAALi)具有最佳的倍率性能、更高的放電比容量和更好的循環(huán)性能。樣品LMO@2%PAALi在0.2C倍率下初始放電比容量為127.2 mAh·g~(-1),在10C下放電容量仍然可以到達97.3 mAh·g~(-1),在1 C倍率下經(jīng)過100次循環(huán)以后,樣品LMO@2%PAALi循環(huán)效率能夠達到88.4%。(3)研究不同類型粘接劑對材料電化學(xué)性能的影響,比較了不同的粘接劑聚乙烯醇(PVA)、聚丙烯酸鋰(PAALi)和LA132對LiMn_2O_4材料的電化學(xué)性能的影響,結(jié)果表明以PVA為粘接劑合成的LiMn_2O_4樣品(LMO_3)具有良好的化學(xué)性能。LMO_3在0.2C下初始放電比容量為128.9 mAh·g~(-1),在1C倍率下經(jīng)過100次循環(huán),其循環(huán)效率為91.8%。在此研究基礎(chǔ)上,分別以不同PAALi/PVA質(zhì)量比(1:5、1:7和1:9)為粘接劑,電化學(xué)測試表明:采用PAALi/PVA質(zhì)量比為1:7(LMO5)時材料具有最高的放電比容量和循環(huán)性能。在0.2C倍率時首次放電比容量可以達到129.1 mAh·g~(-1),在1C倍率下經(jīng)過100次循環(huán),其循環(huán)效率為94.1%。
[Abstract]:With the rapid development of lithium ion batteries, the low cost electrode materials have attracted more and more attention. The spinel LiMn_2O_4 is very competitive. Due to its high safety, rich manganese resources, low price and friendly environment, it is considered to be one of the most potential cathode materials for lithium ion batteries. In recent years, it has been widely used. It is applied to electric vehicles. However, the capacity attenuation of the material is serious due to the reduction of the poplar Taylor effect and the crystallinity caused by the dissolution of the LiMn_2O_4 material Mn~ (3+). A large number of studies have found that the electrochemical performance of LiMn_2O_4 has a great relationship with the synthetic process, the size of the material and the microscopic appearance. This paper mainly reduces the particle size of the material. Size, surface coating of lithium polyacrylate and functional adhesive to improve the electrochemical properties of LiMn_2O_4 materials. The structure, morphology and electrochemical properties of the LiMn_2O_4 materials were studied by electrochemical tests and XRD, SEM and TEM characterization methods. The main contents include: (1) LiNO_3,50 by carbon nanotube assisted solution combustion, LiNO_3,50 %Mn (NO_3) _2 solution was used as raw material and carbon nanotube as fuel, the ultra-fine LiMn_2O_4 material was synthesized successfully. The influence of CNTs on the structure and electrochemical properties of LiMn_2O_4 material was studied. The ratio test showed that the addition of CNTs had a great influence on the electrochemical performance of LiMn_2O_4 materials. The selected L added 7% CNTs as a fuel for the synthesis of L. The iMn_2O_4 material (C7%-LMO) has a high charge discharge ratio. The XRD analysis shows that the sample C7%-LMO has the lowest lattice distortion.SEM analysis, which shows that the grain size of C7%-LMO is 100 nm and has the smallest grain size. The sample C7%-LMO these unique microscopic features guarantee the highest discharge ratio of the sample, and the sample is at 0.. The second discharge ratio of second times is 115.1 mAh. G~ (-1), and it can still reach 77 mAh. G~ (-1) at 10C and 100 cycles at the 1C multiplying rate. The cycle efficiency is 94.8%. reducing grain size can shorten the migration distance of lithium ion in the electrode material. Therefore, C7% -LMO shows the best electrochemical performance. (2) through the solution combustion method, With LiNO_3, Mn (CH3COO) 2. 4H2O and 50%Mn (NO_3) _2 solution as raw materials, the spinel LiMn_2O_4 material was synthesized successfully. The effect of PAALi encapsulation on the structure and properties of the material was studied with PAALi on the structure and properties of LiMn_2O_4. The dissolution of manganese in the LiMn_2O_4 electrode material improves the stability of the LiMn_2O_4 material in the electrolyte. When the coating amount of PAALi is 2%, the coated material (marked as LMO@2%PAALi) has the best ratio of ratio, higher discharge specific capacity and better cycling performance. The initial discharge specific capacity of the sample LMO@2%PAALi is 127.2 m under the 0.2C multiplier. Ah. G~ (-1), the discharge capacity under 10C can still reach 97.3 mAh. G~ (-1). After 100 cycles at the rate of 1 C, the LMO@2%PAALi cycle efficiency of the sample can reach 88.4%. (3) and the effect of different types of adhesive on the electrochemical performance of the material. The effect of the electrochemical properties of n_2O_4 shows that the LiMn_2O_4 sample (LMO_3) synthesized with PVA as a binder has good chemical properties, the initial discharge ratio of.LMO_3 under 0.2C is 128.9 mAh. G~ (-1), and the cycle efficiency is 91.8% under the 1C ratio of 100. 1:5,1:7 and 1:9) are the adhesives. The electrochemical test shows that the material has the highest discharge specific capacity and cycle performance when the mass ratio of PAALi/PVA is 1:7 (LMO5). The first discharge specific capacity can reach 129.1 mAh. G~ (-1) at the 0.2C multiplying ratio and 100 cycles at the 1C ratio, and its cycle efficiency is 94.1%..
【學(xué)位授予單位】：蘭州理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2016
【分類號】：TQ131.11;TM912

【參考文獻】

相關(guān)期刊論文 前10條

1 郭光輝;陳珊;劉芳芳;張利玉;;尖晶石型LiMn_2O_4摻雜研究進展[J];化工新型材料;2013年10期

2 周曉謙;;鋰電池專用粘合劑研究進展[J];化工新型材料;2013年03期

3 王震坡;劉文;王悅;趙春松;張淑萍;陳繼濤;周恒輝;張新祥;;Mg、Ti離子復(fù)合摻雜改性磷酸鐵鋰正極材料及其電池性能[J];物理化學(xué)學(xué)報;2012年09期

4 張春麗;葉學(xué)海;張曉波;付春明;于曉微;肖彩英;;鋰離子電池正極材料錳酸鋰摻雜改性研究[J];無機鹽工業(yè);2012年06期

5 湯小輝;李國希;高桂紅;胡金豐;梁國標;;鋰離子電池正極材料LiCoO_2-LiFePO_4的性能[J];中國有色金屬學(xué)報;2012年01期

6 陳亞;王佳偉;陳白珍;范瑞娟;;尖晶石錳酸鋰納米粒子的制備及其電化學(xué)性能研究[J];廣州化工;2011年12期

7 陳銀良;單承質(zhì);翟清翠;陳曉莉;;乳化炸藥燃燒法制備納米錳酸鋰[J];煤礦爆破;2011年01期

8 廖文明;戴永年;姚耀春;易惠華;熊學(xué);;4種正極材料對鋰離子電池性能的影響及其發(fā)展趨勢[J];材料導(dǎo)報;2008年10期

9 徐茶清,田彥文,翟玉春,王自霞;尖晶石型LiMn_2O_4的溶膠凝膠法制備[J];東北大學(xué)學(xué)報;2004年10期

10 張會情,韓恩山,張林森,楊津;富鋰尖晶石Li_4Mn_5O_(12)的合成[J];電池;2004年03期

，

本文編號：2051958