聚苯乙烯模板法制備鋰離子電池材料及電化學(xué)性能研究
發(fā)布時間：2019-04-03 21:54
【摘要】： 電極材料是制約鋰離子電池迅速發(fā)展的一個關(guān)鍵因素。材料的性能與合成方法有極大關(guān)系,采用傳統(tǒng)高溫固相法能耗大、周期長,所合成材料晶粒和顆粒的可調(diào)控性差,團(tuán)聚現(xiàn)象比較嚴(yán)重,導(dǎo)致性能較差且不穩(wěn)定。在本論文中,我們利用聚苯乙烯(PS)模板的空間限域和調(diào)控作用,成功地制備了一系列電化學(xué)儲能材料。研究結(jié)果表明,聚苯乙烯既能調(diào)控材料的粒徑、形貌和結(jié)構(gòu),又能優(yōu)化材料的物理化學(xué)性質(zhì)。論文主要內(nèi)容包括以下幾個方面: 一、采用聚苯乙烯模板法制備了有序的大孔LiMn_2O_4。不同煅燒溫度影響電極材料的結(jié)構(gòu)、形貌及電化學(xué)性能。結(jié)果表明,700 oC制備的樣品為多孔狀,XRD譜圖證明制備產(chǎn)物為尖晶石結(jié)構(gòu)。組裝成Li/LiMn_2O_4扣式電池,在3.0-4.3V區(qū)間以1C的電流充放電,首次放電比容量為113.8 mAh/g,100次循環(huán)后仍保持初始容量的86.6%,顯示了較好的循環(huán)性能。另外,該材料以2 C倍率放電時,容量仍保持90 mAh/g,具有大功率放電特性,且循環(huán)性能穩(wěn)定。利用循環(huán)伏安方法研究了大孔LiMn_2O_4的電化學(xué)性能和動力學(xué)性質(zhì),計(jì)算了Li+的擴(kuò)散系數(shù)。 二、采用聚苯乙烯模板法制備了高壓電極材料LiNi0.5Mn1.5O4,我們成功合成了孔狀和亞微米LiNi_(0.5)Mn_(1.5)O_4。通過熱分析(DTA、TGA)確定了合成條件,粉末X射線衍射(XRD)表征了產(chǎn)物的晶體結(jié)構(gòu),用掃描電鏡(SEM)觀察產(chǎn)物的形貌,通過循環(huán)伏安(CV)、電池充放電等測試手段詳細(xì)考察了不同條件下制備產(chǎn)物的電化學(xué)性能。比較得出較佳的煅燒溫度為900 oC,在此條件下制備的LiNi_(0.5)Mn_(1.5)O_4在3.5-5.0 V電壓區(qū)間以0.5 C充放電,首次放電容量為102 mAh/g,186次循環(huán)后的容量達(dá)到90.1 mAh/g,為初始容量的88.3%,表現(xiàn)出優(yōu)良的循環(huán)性能。 三、采用聚苯乙烯(PS)模板法合成了LiCoO_2、LiFePO_4、Co_3O_4和NiO四種電極材料。通過控制合成溫度,燒結(jié)時間,升溫速度以及聚合物模板的粒徑,所制備得到的電極材料形貌新穎,顆粒小,結(jié)晶完美。采用粉末X射線衍射(XRD)表征了各種產(chǎn)物的晶體結(jié)構(gòu),用掃描電鏡(SEM)觀察產(chǎn)物的形貌,通過循環(huán)伏安(CV)和電池充放電等測試手段初步考察了LiCoO_2、LiFePO_4、Co_3O_4和NiO的電化學(xué)性能。
[Abstract]:Electrode material is a key factor restricting the rapid development of Li-ion batteries. The properties of the materials have a great relationship with the synthesis method. The traditional high temperature solid phase method has the advantages of large energy consumption, long period, poor controllability of grains and particles, and serious agglomeration, which leads to poor and unstable properties of the synthesized materials. In this thesis, we have successfully prepared a series of electrochemical energy storage materials by using the space limit and regulation of polystyrene (PS) template. The results show that polystyrene can not only control the particle size, morphology and structure of the material, but also optimize the physical and chemical properties of the material. The main contents of this paper are as follows: 1. Ordered macroporous limn _ 2O _ 4 was prepared by polystyrene template method. Different calcination temperatures affect the structure, morphology and electrochemical properties of electrode materials. The results showed that the samples prepared at 700 oC were porous, and the XRD spectra showed that the prepared products were spinel structure. The Li/LiMn_2O_4 button battery was assembled and charged and discharged at a current of 1C in the 3.0 ~ 4.3V range. The initial discharge specific capacity remained 86.6% of the initial capacity after 113.8 mAh/g,100 cycles. It shows better cycle performance. In addition, when the material is discharged at 2 C rate, the capacity of the material is still 90 mAh/g, with high power discharge characteristics, and the cycle performance is stable. The electrochemical and kinetic properties of macroporous limn _ 2O_4 were studied by cyclic voltammetry, and the diffusion coefficients of Li were calculated. Secondly, porous and sub-micron LiNi_ (0.5) Mn_ (1.5) O _ (4) were successfully synthesized by using polystyrene template method to prepare high-pressure electrode material LiNi0.5Mn1.5O4,. The synthesis conditions were determined by thermal analysis (DTA,TGA), the crystal structure of the product was characterized by powder X-ray diffraction (XRD), the morphology of the product was observed by scanning electron microscopy (SEM), and the cyclic voltammetry (CV), was used to observe the morphology of the product. The electrochemical properties of the products prepared under different conditions were investigated in detail by charge-discharge test. The better calcination temperature is 900 oC,. The LiNi_ (0.5) Mn_ (1.5) O _ (3) O _ (4) prepared under this condition is charged and discharged at 0.5 C and the first discharge capacity is 102 mAh/g, in the voltage range of 3.5 脳 5.0 V. After 90.1 mAh/g, cycles, the capacity is 88.3% of the initial capacity, showing excellent cycle performance. Thirdly, four kinds of electrode materials, LiCoO_2,LiFePO_4,Co_3O_4 and nio, were synthesized by polystyrene (PS) template method. By controlling the synthesis temperature, sintering time, heating rate and the particle size of the polymer template, the prepared electrode material has the advantages of novel morphology, small particle size and perfect crystallization. The crystal structures of the products were characterized by powder X-ray diffraction (XRD). The morphology of the products was observed by scanning electron microscopy (SEM). The LiCoO_2,LiFePO_4, was preliminarily investigated by cyclic voltammetry (CV) and battery charging and discharging. Electrochemical properties of Co_3O_4 and NiO.
【學(xué)位授予單位】：湘潭大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2010
【分類號】：TM912
本文編號：2453613
[Abstract]:Electrode material is a key factor restricting the rapid development of Li-ion batteries. The properties of the materials have a great relationship with the synthesis method. The traditional high temperature solid phase method has the advantages of large energy consumption, long period, poor controllability of grains and particles, and serious agglomeration, which leads to poor and unstable properties of the synthesized materials. In this thesis, we have successfully prepared a series of electrochemical energy storage materials by using the space limit and regulation of polystyrene (PS) template. The results show that polystyrene can not only control the particle size, morphology and structure of the material, but also optimize the physical and chemical properties of the material. The main contents of this paper are as follows: 1. Ordered macroporous limn _ 2O _ 4 was prepared by polystyrene template method. Different calcination temperatures affect the structure, morphology and electrochemical properties of electrode materials. The results showed that the samples prepared at 700 oC were porous, and the XRD spectra showed that the prepared products were spinel structure. The Li/LiMn_2O_4 button battery was assembled and charged and discharged at a current of 1C in the 3.0 ~ 4.3V range. The initial discharge specific capacity remained 86.6% of the initial capacity after 113.8 mAh/g,100 cycles. It shows better cycle performance. In addition, when the material is discharged at 2 C rate, the capacity of the material is still 90 mAh/g, with high power discharge characteristics, and the cycle performance is stable. The electrochemical and kinetic properties of macroporous limn _ 2O_4 were studied by cyclic voltammetry, and the diffusion coefficients of Li were calculated. Secondly, porous and sub-micron LiNi_ (0.5) Mn_ (1.5) O _ (4) were successfully synthesized by using polystyrene template method to prepare high-pressure electrode material LiNi0.5Mn1.5O4,. The synthesis conditions were determined by thermal analysis (DTA,TGA), the crystal structure of the product was characterized by powder X-ray diffraction (XRD), the morphology of the product was observed by scanning electron microscopy (SEM), and the cyclic voltammetry (CV), was used to observe the morphology of the product. The electrochemical properties of the products prepared under different conditions were investigated in detail by charge-discharge test. The better calcination temperature is 900 oC,. The LiNi_ (0.5) Mn_ (1.5) O _ (3) O _ (4) prepared under this condition is charged and discharged at 0.5 C and the first discharge capacity is 102 mAh/g, in the voltage range of 3.5 脳 5.0 V. After 90.1 mAh/g, cycles, the capacity is 88.3% of the initial capacity, showing excellent cycle performance. Thirdly, four kinds of electrode materials, LiCoO_2,LiFePO_4,Co_3O_4 and nio, were synthesized by polystyrene (PS) template method. By controlling the synthesis temperature, sintering time, heating rate and the particle size of the polymer template, the prepared electrode material has the advantages of novel morphology, small particle size and perfect crystallization. The crystal structures of the products were characterized by powder X-ray diffraction (XRD). The morphology of the products was observed by scanning electron microscopy (SEM). The LiCoO_2,LiFePO_4, was preliminarily investigated by cyclic voltammetry (CV) and battery charging and discharging. Electrochemical properties of Co_3O_4 and NiO.
【學(xué)位授予單位】：湘潭大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2010
【分類號】：TM912
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