本文選題：鋰離子電池　切入點(diǎn)：正極材料　出處：《昆明理工大學(xué)》2016年碩士論文

【摘要】：鋰離子電池由于高電壓、高比容量、循環(huán)性能好等特點(diǎn)而受到人們的廣泛關(guān)注。層狀三元正極材料LiNi_(1-x-y)Co_xMn_yO_2因?yàn)榫哂兄T多優(yōu)點(diǎn),被認(rèn)為是最有發(fā)展前景的正極材料之一。本文首先介紹了鋰離子電池的研究背景、發(fā)展歷史、主要特點(diǎn)、研究現(xiàn)狀,然后對(duì)正極材料LiNi_(_(1/3))Co_(_(1/3))Mn_(_(1/3))O_2前驅(qū)體的合成工藝、燒結(jié)工藝進(jìn)行研究,最后研究了不同表面活性劑對(duì)合成正極材料LiNi_(0.5)Co_(0.2)Mn_(0.3)O_2的影響。通過XRD、SEM、EDX、充放電測(cè)試等手段對(duì)材料的結(jié)構(gòu)、形貌和電化學(xué)性能進(jìn)行表征。通過超聲波輔助共沉淀法合成前驅(qū)體Ni_(_(1/3))Co_(_(1/3))Mn_(_(1/3))(OH)_2,研究了不同工藝條件對(duì)制備的納米片狀前軀體Ni(__(1/3))Co_(_(1/3))Mn_(_(1/3))(OH)_2材料性能的影響。研究發(fā)現(xiàn),pH值為合成前驅(qū)體過程中的關(guān)鍵因素。隨著pH值的增加,材料的結(jié)晶度和取向都有所提高；顆粒形貌逐步向納米片形貌轉(zhuǎn)變。隨著溫度的升高,顆粒尺寸逐步增大,團(tuán)聚程度增加。顆粒尺寸最大達(dá)到700nm左右。超聲功率的提高有助于提升材料顆粒的分散度。同時(shí)超聲波的引入有助于納米片的形成。利用氣氛爐常規(guī)燒結(jié)制備了具有亞微米尺寸的LiNi_(1/3)Co_(1/3)Mn_(1/3)O_2正極材料。探討了不同燒結(jié)溫度及燒結(jié)時(shí)間對(duì)材料性能的影響。實(shí)驗(yàn)結(jié)果顯示,在燒結(jié)時(shí)間為10h,溫度為850℃C時(shí),合成的LiNi_(1/3)Co_(1/3)Mn_(1/3)O_2具有最為穩(wěn)定的層狀結(jié)構(gòu),陽離子混排效應(yīng)最低,電化學(xué)性能最為優(yōu)異,在1C的倍率下的首次放電容量為130mAh/g,在5C倍率下放電容量為106mAh/g,容量保持率為81.5%。通過添加不同的表面活性劑合成前驅(qū)體Ni_(0.5)Co_(0.2)Mn_(0.3)(OH)2,再通過高溫固相法燒制成正極材料LiNi_(0.5)Co_(0.2)Mn_(0.3)O_2。研究了不同的表面活性劑對(duì)正極材料LiNi_(0.5)Co_(0.2)Mn_(0.3)O_2結(jié)構(gòu)、形貌以及性能的影響。研究結(jié)果表明,制備的三種正極材料均為典型的α-NaFeO_2層狀結(jié)構(gòu),其中,加入PVP合成的正極材料離子混排度最低。加入PVP和OA合成的前驅(qū)體均表現(xiàn)出明顯的納米片形貌,燒結(jié)后基本保持前驅(qū)體形貌；加入SDBS合成的前驅(qū)體表現(xiàn)為片狀和針狀形貌,燒結(jié)后為明顯針狀形貌。加入PVP合成的正極材料擁有最好的電化學(xué)性能。尤其是在高倍率下充放電過程中,展現(xiàn)出了優(yōu)秀的倍率性能和循環(huán)性能。
[Abstract]:Lithium ion batteries have attracted much attention because of their high voltage, high specific capacity and good cycling performance. The layered ternary cathode material LiNi_(1-x-y)Co_xMn_yO_2 has many advantages, such as high voltage, high specific capacity and good cycling performance. It is considered to be one of the most promising cathode materials. This paper first introduces the research background, development history, main characteristics, research status of lithium ion battery, and then studies the synthesis process and sintering process of the cathode material LiNi_(_(1/3))Co_(_(1/3))Mn_(_(1/3))O_2 precursor. Finally, the effect of different surfactants on the structure of LiNi_(0.5)Co_(0.2)Mn_(0.3)O_2 was studied. The morphology and electrochemical properties were characterized by ultrasonic assisted coprecipitation method. The precursor NiSP was synthesized by ultrasonic assisted coprecipitation. It was found that the pH value of the precursor was 1 / 3 / 1 / 3 / 1 / 3 / 1 / 3 respectively. The effects of different technological conditions on the properties of the prepared nanoflake Ni(__(1/3))Co_(_(1/3))Mn_(_(1/3))(OH)_2 were studied. It was found that the pH value was the precursor of synthesis. Key factors in the body process. As pH increases, The crystallinity and orientation of the materials have been improved, and the morphology of the particles has gradually changed to the morphology of the nanocrystalline. With the increase of temperature, the particle size increases gradually. The maximum particle size is about 700nm. The increase of ultrasonic power is helpful to improve the dispersion of material particles. At the same time, the introduction of ultrasonic wave is helpful to the formation of nanocrystals. The effects of sintering temperature and sintering time on the properties of LiNi_(1/3)Co_(1/3)Mn_(1/3)O_2 cathode materials with submicron size are discussed. When the sintering time is 10 h and the temperature is 850 鈩，

本文編號(hào)：1653430