本文選題：鋰離子電池 + 正極材料　； 參考：《蘇州大學(xué)》2016年碩士論文

【摘要】：近年來(lái),隨著經(jīng)濟(jì)的發(fā)展,鋰離子電池被認(rèn)為是混合電動(dòng)汽車和電動(dòng)汽車最具發(fā)展前景的一部分。到目前為止,許多國(guó)內(nèi)外的研究人員致力于改善富鋰層狀正極材料的電化學(xué)性能,來(lái)提高鋰離子電池的能量密度及功率密度,以滿足大眾對(duì)能源的需求。然而富鋰層狀正極材料在充放電過(guò)程中其首次不可逆容量損失大,倍率性能差,電壓降等諸多問(wèn)題也限制其進(jìn)一步發(fā)展。因此,如何提升富鋰層狀正極材料的電化學(xué)性能已經(jīng)成為當(dāng)前研究的重點(diǎn)和難點(diǎn)。本文研究的主要內(nèi)容(1)通過(guò)Zr元素取代Li_2MnO_3中Mn元素改善0.6Li[Li_(1/3)Mn_(2/3)]O_2·0.4LiMn_(5/12)Ni_(5/12)Co_(1/6)O_2材料循環(huán)性能和電壓下降問(wèn)題;(2)通過(guò)ZrO_2包覆0.6Li[Li_(1/3)Mn_(2/3)]O_2·0.4LiMn_(5/12)Ni_(5/12)Co_(1/6)O_2材料改善其循環(huán)性能。本論文工作內(nèi)容如下:(1)采用噴霧干燥法制備一系列0.6Li[Li_(1/3)Mn_(2/3)(_(1-x))Zr_(2/3)x]O_2·0.4LiMn_(5/12)Ni_(5/12)Co_(1/6)O_2(0≤x≤10%)富鋰層狀正極材料。XRD、XPS、SEM結(jié)果表明Zr元素的引入并未改變材料的層狀結(jié)構(gòu)和晶體形貌。HRTEM結(jié)果表明Zr元素可以穩(wěn)定材料的晶體結(jié)構(gòu)。當(dāng)Zr含量為4%時(shí),材料的電化學(xué)性能最好。在2.0到4.8 V電壓范圍,充放電20 mA g~(-1)下,Zr4%的樣品首次放電比容量達(dá)到261 mA h g~(-1),循環(huán)100圈后,容量保持率為84%,遠(yuǎn)高于未取代的樣品。此外,Zr4%的樣品循環(huán)100圈后呈現(xiàn)了0.16 V的最小電壓降。(2)首先通過(guò)噴霧干燥法成功合成0.6Li[Li_(1/3)Mn_(2/3)]O_2·0.4LiMn_(5/12)Ni_(5/12)Co_(1/6)O_2(簡(jiǎn)稱LNMCO),然后通過(guò)溶液法制備一系列ZrO_2包覆LNMCO復(fù)合材料。XRD、XPS和TEM分析結(jié)果表明ZrO_2僅僅堆積在LNMCO樣品的表層,并沒(méi)有改變LNMCO樣品的晶體結(jié)構(gòu)。在這些樣品中,1.5%ZrO_2-LNMCO樣品首圈放電比容量高達(dá)279.3mA h g~(-1),首圈庫(kù)倫效率高達(dá)87.2%,不可逆容量損失僅有55.3 mA h g~(-1),當(dāng)循環(huán)70圈以后,放電比容量為244.3 mA h g~(-1),電化學(xué)性能遠(yuǎn)遠(yuǎn)高于未包覆樣品。但是在不同倍率充放電時(shí),ZrO_2包覆LNMCO樣品的倍率性能比較差,說(shuō)明還需要進(jìn)一步改進(jìn)實(shí)驗(yàn)方法。
[Abstract]:In recent years, with the development of economy, lithium ion battery is considered as the most promising part of hybrid electric vehicle and electric vehicle.Up to now, many researchers at home and abroad have been working to improve the electrochemical performance of lithium-rich layered cathode materials to improve the energy density and power density of lithium-ion batteries, in order to meet the energy needs of the public.However, many problems such as the loss of the first irreversible capacity, the poor performance of the rate and the voltage drop of the lithium-rich layered cathode materials in charge and discharge process also limit their further development.Therefore, how to improve the electrochemical performance of lithium-rich layered cathode materials has become the focus and difficulty of current research.The main content of this paper is to improve the cyclic performance of 0.6Li by replacing mn in Li_2MnO_3 with Zr element. (1 / 3 / 3 / 3)) O2 0.4LiMn_(5/12)Ni_(5/12)Co_(1/6)O_2 material cycle performance and voltage drop problem are improved by ZrO_2 coated 0.6Li [1 / 3 / 3 / 0] O\ -2 0.4LiMn_(5/12)Ni_(5/12)Co_(1/6)O_2 material.The main work of this thesis is as follows: (1) A series of 0.6Li [Li_(1/3)Mn_(2/3)(_(1-x))Zr_(2/3)x] O _ 2 0.4LiMn_(5/12)Ni_(5/12)Co_(1/6)O_2(0 鈮，

本文編號(hào)：1746768