10384 9925011 UDC ( ) ( ) 2002.5 2002.5
The preparation, characterization and performance of nano-carbon/composite as the anodic materials for lithium-ion batteries By Maohui, Chen Supervisors Prof. Zugeng, Lin Dr. Guotao, Wu A thesis presented to the University of Xiamen in fulfillment of the thesis requirement for the degree of Master of Philosophy In Physical Chemistry Xiamen, Fujian, P.R.China, 2002
The preparation, characterization and performance of nano-carbon /composite as the anodic materials for lithium-ion batteries A-1 A-3 1 1.1 1 1.1.1 1 1.1.2 2 1.1.3 3 1.1.3a 1.1.3b 1.1.3c 3 5 6 1.2 8 1.2.1 8 1.2.2 10 1.3 / 12 1.3.1 13 1.3.1.1 1.3.1.2 1.3.1.3 1.3.1.4 13 20 23 24 1.3.2 24 1.3.2.1 1.3.2.2 1.3.2.3 24 25 25 1.4 26 28 I
31 2.1 31 2.1.1 31 2.1.1.1 Ni-Mg-O 31 2.1.1.2 Co-Mg-O 31 2.1.2 32 2.1.2.1 Ni-Mg-O 32 2.1.2.2 Co-Mg-O 32 2.1.2.3 33 2.1.3 34 2.1.3.1 34 2.1.3.2 34 2.1.4 35 2.1.4.1 35 2.1.4.2 36 2.1.4.3 36 2.2 37 2.2.1 X XRD 37 2.2.2 TEM 37 2.2.3 SEM 38 2.2.4 39 2.2.5 Raman 39 2.2.6 ICP/AES 40 2.2.7 CHON 41 2.2.8 (CV) 41 43 44 3.1 Ni-Mg-O 44 3.1.1 Ni-Mg-O CH4 45 3.1.2 Ni-Mg-O CO 54 3.1.3 Ni-Mg-O C2H2 61 3.2 Co-Mg-O 65 3.3 70 3.4 75 3.5 79 81 II
83 4.1 SnO 83 4.2 SnO2 89 4.3 92 93 94 III
Ni-Mg-O 500 600 700 290mAh/g254mAh/g202mAh/g 372mAh/g272mAh/g148mAh/g 600 700 430mAh/g160mAh/g 255.9mAh/g 650 750 675mAh/g350.9mAh/g ( 1000) SEI A-1
Ni-Mg-O - - Co-Mg-O Ni-Mg-O SnO SnO 2 SnO/CNT SnO 2 /CNT 767mAh/g500mAh/g / 400-500ºC SnO 2 /CNT Li 2 O XRD, A-2
The preparation, characterization and performance of nano-carbon/composite as the anodic materials for lithium-ion batteries Abstract The first part of the dissertation addresses the shape, structure and electrochemical performance of various nano-size carbon materials as the anodic materials for lithium ion batteries. The electrochemical properties of the materials have been found to be not only closely related to their intrinsic structures, but be affected by their various shapes. Both factors play the role together in the process of lithium inserted in the materials. In our samples, with the increase of preparation temperature, the d 002 values decreased, the degree of crystallinity decreased, and the specific capacity increased respectively. The first reversible capacities were 290mAh/g, 254mAh/g, 202mAh/g for carbon nanotubes produced by methane at 500, 600and 700; 372mAh/g, 272mAh/g, 148mAh/g for carbon nanotubes produced by carbon monoxide at 500, 600and 700; 430mAh/g, 160mAh/g for carbon nanotubes produced by acetylene at 600 and 700 ; 255.9mAh/g for carbon nanoballs produced by the catalyst Co:Mg:O=3:1:4; 675mAh/g, 350.9mAh/g for carbon nanotubes produced by the template method at 650and 750 respectively. The mechanism of lithium insertion into our carbon materials is similar as that of carbon produced by the pyrolysis of hydrocarbon below 1000. The hysteresis during lithium insertion into the samples may be related to the defective sites. And, the great irreversible capacity may be mostly associated with both the electrolyte decomposition and the formation of solid electrolyte interphase (SEI) on the carbon surface. Different preparation methods modify the mechanism of nano-size carbon growth. The Ni-Mg-O catalyst possesses the general adsorption/pyrolysis-transfer/diffusion-deposition mechanism. As for the Co-Mg-O catalyst, with the higher content of cobalt, the content of A-3
cobalt reduced during the reaction is more, the active sites are more, the rate of carbon formation increases, and the high content of carbon nanoballs can be obtained in the products. However, the Co-Mg-O catalyst with the low content of cobalt has a similar mechanism as that of the Ni-Mg-O catalyst due to the low content of cobalt reduced during the reaction. Because the alumina template has the confine effect and the catalyst activity by itself, carbon is mainly deposited along the template s pore during the preparation of carbon nanotube by the template method. The second study looks the electrochemical properties of the carbon nanotube composite. Both SnO/Carbon nanotube and SnO 2 /Carbon nanotube have shown a better electrochemical performance, which includes the reversible capacity and the cycle life, as the anode active materials for lithium ion batteries. The first reversible capacities were 767mAh/g, 500mAh/g for SnO/Carbon nanotube and SnO 2 /Carbon nanotube. In our opinion, the good electronic conductivity and ductility of the carbon nanotube matrix, a high dispersion of the SnO/SnO 2 and the specific mechanical performance of the composite work unison to induce the good performance of the carbon nanotube composite. Supposed that SnO/SnO 2 is reduced to tin, for example that SnO 2 /CNT is performed by the heat treatment at 400-500ºC under H 2 flow, the irreversible capacity during the reduction-displacement of tin oxide will be decreased greatly. Keywords lithium ion batteries, carbon nanotube, carbon nanoball, catalytic pyrolysis, the template method, porous alumina template, the electrochemical performance, the mechanism of lithium insertion, the mechanism of growth, Raman spectra, XRD, CV, Charge/Discharge test A-4
2002.5 / 1.1 1.1.1 1987 Moli Energy Li-MoS 2 1990 2 Sony [1] [1-3] PTC - 1 -
[3] 1 3V 4V 1000 2~3% 1-1 [4] 1-1 23%14%63% [4] 1.1.2 1-2 - 2 -
2002.5 1-2 1.1.3. 1-3 - [4] 1-3 - 1.1.3a LiC 6 372mAhg -1 1-1 - 3 -
1-1 / MCMB (MCMB) PFA-C Polyacene(PAS) Poly Paraphenylene LGH 0.2V 15~20% SEISolid Electrolyte Interface [5] 200mAhg -1 100mAhg -1 SEI 680mAhg -1 [5-7] BNP [8] - 4 -
2002.5 Li x C n xli + + xe + C n LiC 2 [9, 10] 1.1.3b [11] xli + + xe + Li x MX Li x+ xmx x M X, LiCoO 2, LiNiO 2,LiMn 2 O [12] 4, LiCoO 2,, LiMn 2 O 4,, LiCoO 2,,,, LiCoO 2 LiNiO 2-5 -
(LiNi 1-y Co y O 2 ) (EV, HEV) 3 LiNiO 2 LiNiO 2 LiCoO 2 Li x FePO 4 [13, 14] 1.1.3c [15] 1-2 / cp (25) (25) Ethylene Carbonate EC 34.6 238 1.9(40) 95.3 Proylene Carbonate PC -49 241 2.54 64.4 Dimethysulfoxide DMSO 18.5 189 1.99 46.5 Dimethylformamide DMF -61 158 0.79 36.7 N-Methylpyrrolidinone NMP -24 204 1.66 32 Dimethylsulfite DMS -141 126 0.77(30) 22.5 Tetrahydrofuran THF -108 65 0.46 7.39 1,2-Dimethoxyethane DME -69 85.2 0.45 7.2 2-Methyltetrahydrofuran 2-MeTHF -75 79 0.46 6.2 Diethylcarbonate DEC -43 118.1 0.748 2.82 Dimethylcarbonate DMC 2~4 90 0.585 3.12-6 -
2002.5 [16, 17] 1 2 3 4 5 6 1-2 LiClO 4 LiAsF 6 LiPF 6 LiBF 4 LiCF 3 SO 3 LiN(CF 3 SO 2 ) 2 LiClO 4 Dioxolane LiAsF 6 LiCF 3 SO 3 LiPF 6 LiPF 6 /EC+DMC [18] - 7 -
Degree papers are in the Xiamen University Electronic Theses and Dissertations Database. Full texts are available in the following ways: 1. If your library is a CALIS member libraries, please log on http://etd.calis.edu.cn/ and submit requests online, or consult the interlibrary loan department in your library. 2. For users of non-calis member libraries, please mail to etd@xmu.edu.cn for delivery details.