本文關(guān)鍵詞： 富鋰正極材料 氧化鎳負(fù)極材料 摻雜 空心 鋰離子電池　出處：《合肥工業(yè)大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：鋰離子電池具有能量密度高、循環(huán)壽命長、無記憶效應(yīng)等諸多優(yōu)點(diǎn),已經(jīng)成功應(yīng)用于便攜式電子設(shè)備中,同時(shí)正在大規(guī)模地向電動(dòng)汽車和儲(chǔ)能設(shè)備領(lǐng)域發(fā)展。然而目前的鋰離子電池性能已經(jīng)無法滿足上述日益增長的需求。為了提高鋰離子電池的性能,發(fā)展新型的鋰離子電池正、負(fù)極材料具有重要意義。本論文在深入調(diào)研高容量富鋰正極材料(LR-MNC,實(shí)際容量250 mAh g-1)和氧化鎳負(fù)極材料(NiO,理論容量718 mAh g-1)的研究進(jìn)展基礎(chǔ)上,開展了基于碳酸鹽共沉淀法制備富鋰正極材料Li1.2Ni0.13Co0.13Mno.54O2及摻雜改性、微乳液法輔助制備一維空心結(jié)構(gòu)NiO及電化學(xué)性能研究工作。主要內(nèi)容如下:針對(duì)LR-MNC容量衰減、電壓衰減以及倍率性能和熱穩(wěn)定性差的問題,對(duì)碳酸鹽共沉淀法結(jié)合后續(xù)高溫煅燒制備的表面多孔的球狀Lii.2Ni0.13Co0.13Mn0.54O2分別進(jìn)行了 Al、F單一元素?fù)诫s和共摻雜改性的研究。A1F共摻雜結(jié)合了 Al、F單一元素?fù)诫s的優(yōu)勢(shì),可以有效緩解由層狀結(jié)構(gòu)向尖晶石結(jié)構(gòu)的轉(zhuǎn)變,因而可以抑制容量衰減和電壓衰減:在0.5 C循環(huán)150次后,放電容量為217 mAh g-1且容量保持率為88.21%,平均放電電壓衰減僅為0.4019 V。另一方面,A1F共摻雜可以提高離子和電子傳導(dǎo)率,進(jìn)而提升倍率性能,10C下的放電容量高達(dá)157 mAhg-1。此外,A1F共摻雜使材料的熱穩(wěn)定性得到改善,初始放熱峰高達(dá)273℃且總產(chǎn)熱量低至221 Jg-1。針對(duì)NiO在充放電過程中的體積膨脹問題,采用微乳液水核提供合成一維材料的模板,并利用奧氏熟化機(jī)制制備了一維空心NiO負(fù)極材料,具有均勻的形貌和優(yōu)異的電化學(xué)性能。0.1 C首次放電容量為1086.2 mAh g-1,首次庫倫效率為75.00%, 100次循環(huán)后放電容量保持為884.8 mAh g-1; 5 C首次放電容量為429.7 mAh g-1,經(jīng)過80次循環(huán)后容量為492.5 mAh g-1; 10 C高倍率下的平均放電容量也高達(dá)363.0 mAh g-1。原反應(yīng)體系放大10倍制備的NiO材料或利用回收油相制備的NiO材料均具有一維空心結(jié)構(gòu),電化學(xué)性能較好,證明了產(chǎn)物可以利用放大反應(yīng)大量制備,并可以重復(fù)利用油相,降低成本,減少廢棄有機(jī)試劑的污染。
[Abstract]:Lithium ion batteries have been successfully used in portable electronic devices because of their high energy density, long cycle life and no memory effect. At the same time, the field of electric vehicles and energy storage equipment is developing on a large scale. However, the current performance of lithium ion battery can no longer meet the increasing demand, in order to improve the performance of lithium ion battery. It is of great significance to develop new cathode materials for lithium-ion batteries. In this paper, LR-MNC with high capacity lithium-rich cathode materials has been investigated. On the basis of the actual capacity of 250 mAh g-1) and nickel oxide anode material nio, theoretical capacity of 718 mAh g-1). Lithium-rich cathode material Li1.2Ni0.13Co0.13Mno.54O2 was prepared by carbonate coprecipitation method and modified by doping. The main contents are as follows: aiming at the problems of LR-MNC capacity attenuation, voltage attenuation and poor rate performance and thermal stability. The porous spherical Lii.2Ni0.13Co0.13Mn0.54O2 prepared by carbonate coprecipitation combined with subsequent high temperature calcination was prepared respectively. Study on F single element doping and co-doping modification. A1F co-doping combined with the advantages of Alf single element doping can effectively alleviate the transition from layered structure to spinel structure. Therefore, the capacity attenuation and voltage attenuation can be suppressed: the discharge capacity is 217 mAh g ~ (-1) and the capacity retention rate is 88.21% after 150th cycle at 0. 5C. The average voltage attenuation is only 0.4019 V. on the other hand, co-doping of A1F can improve ion and electron conductivity, and then improve the rate performance. The discharge capacity at 10C is as high as 157mAhg-1.In addition, co-doping of A1F improves the thermal stability of the materials. The initial exothermic peak was as high as 273 鈩，

本文編號(hào)：1479640