碳纳米管（CNTs）作为锂离子电池负极和导电剂的应用
发布时间：2018-09-14 11:53
【摘要】：碳纳米管作为锂离子电池负极材料,性能与其形貌结构有着密切的关系。本文利用CVD工艺合成了具有不同形貌结构的两种碳管膜并测试其锂电性能。缺陷较多的碳管膜(CNT-2)的比表面积为163.6 cm~2 g~(-1),大于结晶性良好的CNT~(-1)碳管膜(122.7 cm~2 g~(-1))的比表面积,在3000 m Ah g~(-1)高电流密度下稳定循环500次后,CNT-2的可逆容量仍保持在108 m Ah g~(-1),而CNT~(-1)的可逆容量则只有61m Ah g~(-1)。上述结果表明CNT-2的缺陷结构有利于锂离子的传输,更适合用于高功率电池。本文重点研究了Ti O_2改性对CNTs锂电性能的影响。通过在碳纳米管前驱体溶液中引入钛酸四丁酯作为钛源,制备CNTs/Ti O_2复合膜。实验发现当钛酸四丁酯的含量为19 wt.%时,获得的19.0 wt.%-CNTs/Ti O_2复合膜具有优异的电化学性能,其结构特点是Ti O_2纳米颗粒镶嵌在CNTs表面,Ti O_2主要以金红石相存在,质量分数为17.6 wt.%。在30 m A g~(-1)电流密度下,19.0 wt.%-CNTs/Ti O_2首次充放电的库仑效率为60.3%,可逆容量达到500 m Ah g~(-1),远高于CNTs(30.3%,350 m Ah g~(-1)),并且在3000 m A g~(-1)电流密度下循环500次后,19.0 wt.%-CNTs/Ti O_2容量稳定在134 m Ah g~(-1),而CNTs为90 m Ah g~(-1)。本文还在Li Fe PO_4前驱体中引入乙酸镍作为催化剂,以乙炔气为碳源,利用气相沉积法,在700℃合成Li Fe PO_4的同时在其表面生长CNTs,原位制备Li Fe PO_4/CNTs复合材料。研究证明:当乙炔流量为12ml/min,乙酸镍为4 wt.%时,制备的Li Fe PO_4/CNTs复合材料具有较好的充放电效率。
[Abstract]:The properties of carbon nanotubes (CNTs) as anode materials for lithium ion batteries are closely related to their morphology and structure. In this paper, two kinds of carbon tube films with different morphologies were synthesized by CVD process and their lithium electrical properties were tested. The specific surface area of the carbon tube film (CNT-2) with more defects is 163.6 cm~2 g ~ (-1), which is larger than that of the CNT~ (-1) carbon tube film (122.7 cm~2 g ~ (-1) with good crystallinity. At a high current density of 3000 m Ah g ~ (-1), the reversible capacity of CNT-2 remains at 108m Ah g ~ (-1) after 500 stable cycles, while the reversible capacity of CNT~ (-1) is only 61m Ah g ~ (-1). The results show that the defect structure of CNT-2 is favorable for lithium ion transport and is more suitable for high power battery. The effect of modification of Ti O _ 2 on the electrical properties of CNTs lithium was studied in this paper. CNTs/Ti O _ 2 composite membrane was prepared by introducing tetrabutyl titanate into carbon nanotube precursor solution as titanium source. It was found that the obtained 19.0 wt.%-CNTs/Ti O _ 2 composite film had excellent electrochemical performance when the content of tetrabutyl titanate was 19 wt.%. The structure of the composite film was characterized by the fact that Ti O _ 2 nanoparticles were embedded on the surface of CNTs in rutile phase, with a mass fraction of 17.6 wt.%.. The Coulomb efficiency of the first charge and discharge is 60.3 at 30mAg-1 current density, and the reversible capacity is 500m Ah g-1, which is much higher than that of CNTs (30.3 / 350m Ah g-1), and the capacity of 19.0 wt.%-CNTs/Ti O2 is stabilized at 134mAh after 500 cycles at the current density of 3000 mAg-1. G ~ (-1) and CNTs were 90 m Ah g ~ (-1). In this paper, nickel acetate as catalyst and acetylene gas as carbon source were introduced into Li Fe PO_4 precursor, Li Fe PO_4 was synthesized at 700 鈩，
本文编号：2242637
[Abstract]:The properties of carbon nanotubes (CNTs) as anode materials for lithium ion batteries are closely related to their morphology and structure. In this paper, two kinds of carbon tube films with different morphologies were synthesized by CVD process and their lithium electrical properties were tested. The specific surface area of the carbon tube film (CNT-2) with more defects is 163.6 cm~2 g ~ (-1), which is larger than that of the CNT~ (-1) carbon tube film (122.7 cm~2 g ~ (-1) with good crystallinity. At a high current density of 3000 m Ah g ~ (-1), the reversible capacity of CNT-2 remains at 108m Ah g ~ (-1) after 500 stable cycles, while the reversible capacity of CNT~ (-1) is only 61m Ah g ~ (-1). The results show that the defect structure of CNT-2 is favorable for lithium ion transport and is more suitable for high power battery. The effect of modification of Ti O _ 2 on the electrical properties of CNTs lithium was studied in this paper. CNTs/Ti O _ 2 composite membrane was prepared by introducing tetrabutyl titanate into carbon nanotube precursor solution as titanium source. It was found that the obtained 19.0 wt.%-CNTs/Ti O _ 2 composite film had excellent electrochemical performance when the content of tetrabutyl titanate was 19 wt.%. The structure of the composite film was characterized by the fact that Ti O _ 2 nanoparticles were embedded on the surface of CNTs in rutile phase, with a mass fraction of 17.6 wt.%.. The Coulomb efficiency of the first charge and discharge is 60.3 at 30mAg-1 current density, and the reversible capacity is 500m Ah g-1, which is much higher than that of CNTs (30.3 / 350m Ah g-1), and the capacity of 19.0 wt.%-CNTs/Ti O2 is stabilized at 134mAh after 500 cycles at the current density of 3000 mAg-1. G ~ (-1) and CNTs were 90 m Ah g ~ (-1). In this paper, nickel acetate as catalyst and acetylene gas as carbon source were introduced into Li Fe PO_4 precursor, Li Fe PO_4 was synthesized at 700 鈩，
本文编号：2242637
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