电化学和化学副反应 电解质和高分子粘接剂的含量
3. Electrode manufacturing process (slurry preparation)电极生产过程(制浆) - dispersibility in the liquid media分散在液体介质中 - viscosity control of the slurry (solvent absorption)浆料的粘度控制
r [W*cm]
1 Resistivity level of the electrode material电极的导电
Percolation curve 渗透曲线
Slope 斜率 Ultimate resistivity level最终的电阻率
0.1510 Nhomakorabea15
vol.% C
Limits for thin film electrodes, but suitable for material comparisons 对薄膜电极有局限性,但适用材料的比较
CIBF2005, April 3rd, 2005
Graphite manufacturing process石墨生产过程 Primary synthetic graphite原生石墨
Carbon precursor 碳前体
selection, crushing Mixing,筛选,粉碎,和混合
Natural graphite天然石墨
Graphite material properties石墨性能
Graphite porosity
10 8 Vads. [[cm3]] 6 4 2 0 0.0 0.2 0.4 0.6 0.8 1.0 Pressure [p/760 Torr]
N2-adsorption N2-desorption
Type III-isotherme III 型等温线
(Brunauer, Emmett, Teller)
mesoporous material 间孔材料 Total graphite surface area 石墨表面积 • geometrical surface area • porosity
几何表面积 多孔性
• surface roughness
2. Energy density optimization能量密度的最优化 • electrode density (compaction properties)电极密度(压实性) • electrolyte and polymer binder content (polymer/electrolyte absorption) • electrochemical and chemical side reactions (surface area)
1.4 1.2
[V] Potential vs. Li/Li
+
1.0 0.8 0.6
10 mm
0.4 0.2 0.0
0
100
200
300
400
1 M LiPF6 in EC/DMC 1:1 (w:w) 10 % PVDF binder
Specific Charge [mAh/g Carbon]
CIBF2005, April 3rd, 2005
• surface defects
表面缺陷 表面粗糙度
CIBF2005, April 3rd, 2005
Graphite conductive additives-positive electrode 正极石墨导电剂 球面电阻Pellet resistivity of LiCoO2
1.4 1.2 电阻 [W cm] 1.0
CIBF2005, April 3rd, 2005
Influence of the carbon conductive additive 碳导电剂的影响
1. Electrode impedance optimization电阻的最优化 Increase of the electronic conductivity增加导电性 (mathematically described by the Percolation Theory or the Effective Medium Theory渗透理论的数学描述)
Advantages of carbon additives in electrochemical applications 碳导电添加剂在电化学应用中的优点
electrical conductivity 导电性 thermal conductivity (graphite in particular) 导热性(特别是石墨) non-toxic and environmentally begnin无毒环境友好 chemically inert化学稳定性 available in high quantity and purity高纯度 low weight 低重量 relatively low production costs 相对低的制造成本
Graphite conductive additives-negative electrode 负极石墨导电剂
Influence of the specific BET surface area比表面积的影响
26 24 22 20 18 16 14 12 10 8 6 4 2 0
Irreversible Capacity [%]
KS-type SFG-type T-type SLM-type SLX-type NP-type
1 M LiPF6 in EC/DMC 1:1 (w:w) 10 % PVDF binder
0
2
4
6
8
10
12
14
16
2
18
20
Specific BET Surface Area [m /g]
CIBF2005, April 3rd, 2005
CIBF2005, April 3rd, 2005
Influence of the carbon conductive additive 碳导电剂的影响
1. Electrode impedance optimization电极电阻的最优化
Increase of the ionic conductivity增加离子导电性
Carbon Conductive Additives for Lithium Ion Batteries 锂离子电池的碳导电添加剂
Michael E. Spahr, Ye Bing
CIBF2005, April 3rd, 2005
Carbon conductive additives for lithium ion batteries Outline 大纲
KS6 KS15 SFG15 MX15
U I
Cathode bar
I
B
0.8
0.6 0.4
0.2
0.0 4 5 6 7 8 9 10
石墨含量 [%]
CIBF2005, April 3rd, 2005
Graphite conductive additives - negative electrode 负极石墨导电剂 Graphite additives in the negative electrode石墨在负极中
Graphite conductive additives-negative electrode 负极石墨导电剂 Compatibility with propylene carbonate丙烯碳酸盐的相容性
1.5
Potential vs. Li/Li [V]
SFG6
1.0
+
SFG44
0.5
SFG15 Electrolyte: 1 M LiPF6 in EC/PC 1:1 (w:w)
25
Isometric 各向同性 Anisometric 各向异性
DBPA [g/100 g C]
15 10 5 0
0.05
0.07
0.10
0.06
0.09
0.19
0.06
CIBF2005, April 3rd, 2005
4. Graphite or carbon black? 选择石墨还是碳黑
5. Conclusions 结论
CIBF2005, April 3rd, 2005
Carbon conductive additives 碳导电添加剂
1. primary synthetic and natural graphite powders原生合成和天然石墨粉 (Xylene density: 2.230-2.267 g cm-3, 二甲苯密度 graphite interlayer distance石墨层距 c/2: 0.3354-0.3360 nm) 2. conductive carbon blacks 导电碳黑
Raw purified graphite (min. 99 % C)初纯石墨
conditioning, grinding, classifying, mechanical/chemical treatment, 处理,研磨,分类,机械/化学处理
Final graphite product产品
CIBF2005, April 3rd, 2005
(electrolyte retention and lithium ion transport rate in the electrode pores 电解液的保持和在电极孔中锂离子的传送速率)
- electrolyte absorption 电解液的吸收 - control of electrode pore structure电极多孔结构的控制