鋰離子電池的碳導(dǎo)電添加劑

1、Outline 大綱大綱1. Introduction (介紹） Why carbon materials as conductive matrix? 為什么碳材料可以作為導(dǎo)電體為什么碳材料可以作為導(dǎo)電體 Role of the carbon conductive matrix,碳導(dǎo)電體的作用2. Graphite as conductive additive 石墨作為導(dǎo)電添加劑3. Carbon black as conductive additive 碳黑作為導(dǎo)電添加劑4. Graphite or carbon black? 選擇石墨還是碳黑5. Conclusions 結(jié)論 electr

2、ical conductivity 導(dǎo)電性 thermal conductivity (graphite in particular) 導(dǎo)熱性(特別是石墨) non-toxic and environmentally begnin無毒環(huán)境友好 available in high quantity and purity高純度 chemically inert化學(xué)穩(wěn)定性 low weight 低重量 relatively low production costs 相對(duì)低的制造成本 (Xylene density: 2.230-2.267 g cm-3, 二甲苯密度 graphite interla

3、yer distance石墨層距 c/2: 0.3354-0.3360 nm)1. Electrode impedance optimization電阻的最優(yōu)化 Increase of the electronic conductivity增加導(dǎo)電性(mathematically described by the Percolation Theory or the Effective Medium Theory滲透理論的數(shù)學(xué)描述) Ultimate resistivity level最終的電阻率Percolation curve滲透曲線滲透曲線r r W W*cm0.11vol.% C5101

4、5Slope 斜率Resistivity level of the electrode material電極的導(dǎo)電Limits for thin film electrodes, but suitable for material comparisons對(duì)薄膜電極有局限性,但適用材料的比較 Increase of the ionic conductivity增加離子導(dǎo)電性 (electrolyte retention and lithium ion transport rate in the electrode pores 電解液的保持和在電極孔中鋰離子的傳送速率)- electrolyte

5、absorption 電解液的吸收- control of electrode pore structure電極多孔結(jié)構(gòu)的控制2. Energy density optimization能量密度的最優(yōu)化 electrode density (compaction properties)電極密度(壓實(shí)性) electrolyte and polymer binder content (polymer/electrolyte absorption) 電解質(zhì)和高分子粘接劑的含量電解質(zhì)和高分子粘接劑的含量 electrochemical and chemical side reactions (sur

6、face area) 電化學(xué)和化學(xué)副反應(yīng)電化學(xué)和化學(xué)副反應(yīng)3. Electrode manufacturing process (slurry preparation)電極生產(chǎn)過程(制漿)- viscosity control of the slurry (solvent absorption)漿料的粘度控制- dispersibility in the liquid media分散在液體介質(zhì)中1. Electrode impedance optimization電極電阻的最優(yōu)化Properties性能c/2=. 3354 nm0 a=0.246 nml=0.1421 nmABAPrismat

7、ic SurfaceBasal Plane SurfaceHexagonalRombohedralABCAc=1.0072 nmGraphite crystal structure石墨的晶體結(jié)構(gòu)1 mmGraphite texture石墨質(zhì)地Graphite porosity surface roughness 表面粗糙度 porosity 多孔性 geometrical surface area 幾何表面積Total graphite surface area石墨表面積 surface defects 表面缺陷0.00.20.40.60.81.00246810 Vads. cm3Pressu

8、re p/760 TorrN2-adsorptionN2-desorptionBCathode barUII456789100.00.20.40.60.81.01.21.4 電阻電阻 W W cm石墨含量石墨含量 % KS6 KS15 SFG15 MX15020406080100100150200250300350400 Specific charge mAh/gCycle number Li+ insertion Li+ de-insertionMCMB/SFG6MCMBElectrolyte:1 M LiPF6 in EC/DMC (1:1)Graphite additives in th

9、e negative electrode石墨在負(fù)極中Binder: 10 % PVDF01002003004000.00.20.40.60.81.01.21.4 Specific Charge mAh/g CarbonPotential vs. Li/Li+ V1 M LiPF6 in EC/DMC 1:1 (w:w)10 % PVDF binderTIMREX SFG44Double function intercalation host雙重功效嵌入主體0246810121416182002468101214161820222426 Irreversible Capacity %Specif

10、ic BET Surface Area m2/g KS-type SFG-type T-type SLM-type SLX-type NP-typeInfluence of the specific BET surface area比表面積的影響1 M LiPF6 in EC/DMC 1:1 (w:w)10 % PVDF binderCompatibility with propylene carbonate丙烯碳酸鹽的相容性0.00.51.01.52.00.00.51.01.5 Potential vs. Li/Li+ Vx in LixC6SFG6SFG15SFG44Electrolyte

11、:1 M LiPF6 in EC/PC 1:1 (w:w)0510152025050100150200250 DBPA g/100 g C BET SSA m2 g-1Isometric各向同性Anisometric各向異性Electrode density increase電極密度增加0400800120016000.81.21.62.02.4 Press Density g/cm3Pressure kg/cm2 MCMB SFG15 MCMB+20 % SFG15graphite real density Vapor grown fibers氣相生長(zhǎng)碳纖維50 nm500 nmCarbon

12、 nanotubes碳納米管 electric conductivity導(dǎo)電 thermal conductivity導(dǎo)熱 flexural modulus彎曲模量 Thermal process熱過程Cracking裂化:CxH2x+z + Energy CxHy + (x + z/2 - y/4) H2 (zy)Synthesis合成: CxHy x C + y/2 H2Separated process steps of heat generation and carbon black formation熱產(chǎn)生和碳黑形成的過程 Acetylene process乙炔化n C2H2 2n

13、C + n H2 + Energy carbon black formation at temperatures below 2000 Cabove 2000 C partial graphitization occurs. 在2000 C形成碳黑, 2000 C以上部分石墨化Cracking:裂解CxH2x+z + Energy CxHy + (x + z/2 - y/4) H2 (zy)Synthesis:合成 CxHy x C + y/2 H2Combustion燃燒:CxH2x+z + (3x/2 + z/4) O2 x CO2 + (x + z/2) H2O + EnergyCrac

14、king:裂解CxH2x+z + Energy CxHy + (x + z/2 - y/4) H2 (zy)Synthesis:合成 CxHy x C + y/2 H2Vaporization of the feed stock and pyrolysis down to C1 and C2 units氣化原料和高溫裂解成C1和C2 2. Formation of nuclei or growth centers for primary carbon particles 原碳粒子的生長(zhǎng)中心或核的形成3. Growth and fusion of the nuclei to concentric

15、 primary particles核的生長(zhǎng)和融合成同心的原生碳顆粒4. Agglomeration of the primary particles to primary aggregates原生顆粒集聚成原生集聚體5. In some cases a secondary growth: formation of pyrolytic deposit on the agregate surface,在某些情況下,二次生長(zhǎng): 在聚集體表面熱解沉積的形成6. Agglomeration of the aggregates by van-der-Waals forces 聚集體因范德華力而團(tuán)聚7.

16、Eventual aggregation of the agglomerates followed by subsequent coating of carbon observed in the plasma process 團(tuán)聚體的最后形成,跟隨著在等離子過程中可以觀測(cè)到的碳涂覆Partial Oxidation部分氧化Carbon Separation碳分離CarbonTreatment碳處理Oil油GasTreatment氣化處理Silos料倉(cāng)Oxidant氧化劑GranulatingPackaging造粒包裝Burning燃燒End userH2PalletisingWarehouse

17、裝盤,倉(cāng)儲(chǔ)De-dusting去塵TIMCAL carbon black-schematic process flow diagram特密高碳黑生產(chǎn)流程特密高碳黑生產(chǎn)流程ENSACOTM 250Acetylene black乙炔黑(Origin: University of Louvain, Belgium)20 nm20 nmTransition electron microscopy (TEM)(Origin: Prof. Donnet, Mulhouse)Scanning tunneling microscopy(STM)Acetylene black10 x10 nmENSACOTM

18、25010 x10 nmENSACOTM 2505x5 nm(Origin: University of Louvain, Belgium)TEM picture of ENSACOTM 25050 nmHigh structure高結(jié)構(gòu)high void volume高空隙 high oil absorption number (OAN)高吸油值 high DBP absorption高DBP值OAN 170 mL/100 gLow structure低結(jié)構(gòu)low void volume低空隙CB aggregate碳黑聚集體with a high degree of openness an

19、d chaining高空間和鏈結(jié)構(gòu)05010015020011.21.41.61.82Ensaco 250Acetylene blackCompression energythicknessCompression energy kg cmThickness cm05010015020011.21.41.61.82Ensaco 250Acetylene blackCompression energythicknessCompression energy kg cmThickness cm00.050.10.150.20.250.30.50.60.70.80.91Ensaco 250Acetyle

20、ne blackResistivity (ohm.cm)densityCompression energy kg cmPress density g cm-300.050.10.150.20.250.30.50.60.70.80.91Ensaco 250Acetylene blackResistivity (ohm.cm)densityCompression energy kg cmPress density g cm-3Thickness厚度厚度 cmPress density 壓實(shí)密度壓實(shí)密度g cm-3Compaction behavior壓縮行為Compaction energy 壓縮

21、能壓縮能kg cmCompaction energy kg cmENSACO 250Acetylene blackENSACO 250Acetylene blackTEM of ENSACOTM 35050 nm Crystallite Edges 晶體邊 Graphitic石墨面 Planes Amorphous Carbon 無定型碳 Slit Shaped Cavities 裂口空隙 I I II II III III IV IV Surface heterogeneity and surface microstructure表面異質(zhì)和微結(jié)構(gòu)Surface group chemistry

22、表面功能團(tuán)化學(xué) (Temperature-controlled thermodesorption)Carbon black碳黒H2mmole g-1H2Ommole g-1COmmole g-1CO2mmole g-1SuperTM P91.8214.14.6ENSACOTM 350 uperTM PAcetylene B.乙炔黑乙炔黑Ash %灰分0.010.06Volatiles %揮發(fā)物0.100.16Toluene extractables %甲苯析出0.030.05Sulfur ppm硫7618002468101214Sulphates ChlorinesF

23、luorines BrominesNitrates PhosphatesANIONIC IMPURITIESEnsaco 250Acetylene blackppm SO42-Cl-F-Br-NO3-Pontent ppmppmSuperTM PAcetylene B.Al0.81.3Ca8.41.2Co0.10.1Cr24.6Cu0.20.3Fe841K0.50.5Mg10.3Mn0.10.1Mo0.50.5Na82.1Ni0.53.9V0.20.2Zn0.51.2 Carbon blacks with higher structure show percol

24、ation threshold at lower carbon content高結(jié)構(gòu)碳黑的滲透值較低 The higher the OAN is the less carbon black is needed for a given resitivity level of the electrode達(dá)到同樣的導(dǎo)電值吸油值大的碳黑需要量小246810121416048121620 Resistivity W W cmC content % ENSACOTM 350 G ENSACOTM 250 G SUPERTM P+ LiMn2O424681012141602468101214 Resisti

25、vity W W cmC content % SUPER PTM ENSACOTM 350G ENSACOTM 250 G+ LiCoO205010015020025030035040002004006008001000Structure結(jié)構(gòu)結(jié)構(gòu)(DBP absorption)Specific surface area 比表面積比表面積 (m/g)MMM Process/MMM法法Furnace Process爐黑爐黑Thermal Process熱黑熱黑AcetyleneBlack乙炔黑乙炔黑GaseificationProcess氣化法氣化法Channel Process/槽黑槽黑Afte

26、rtreated furnaceLamp Process燈黑燈黑 High polymer binder absorption decreases mechanical electrode stability 吸收更多的粘合劑會(huì)降低電極的機(jī)械穩(wěn)定性 High electrolyte absorption could lead to strong swelling of the electrode 高電解液的吸收會(huì)導(dǎo)致電極的膨脹 High viscosity of the electrode slurry/higher demand of solvent 電極的高粘度需要更多的溶劑 High s

27、urface area leads to chemical and electrochemical side reactions especially in the charged state of the electrodes 高比表面積會(huì)導(dǎo)致化學(xué)和電化學(xué)的副反應(yīng).特別是在充電狀態(tài)- Higher specific charge losses in the negative electrode related to SEI formation due to increased electrode area在負(fù)極中的更高的比電荷損失.這是由于表面積增加導(dǎo)致SEI的形成-Higher elect

28、rolyte oxidation rate at the charged positive electrode 正極充電時(shí)的電解液高氧化率- Higher dissolution rate of manganese in the electrolyte in the case of a LiMn2O4 spinel positive electodes尖晶石電極下,在電解液中的Mn的高溶解 Effects depend on the carbon concentration and might be negligible 這些效應(yīng)取決于碳黑濃度,也可能被忽略.Absorption stiffn

29、ess changes in an intensive mixer在強(qiáng)攪拌下的吸收硬度0.00.51.01.52.005101520253035 Absorption stiff ness吸收硬度吸收硬度 mL/5 gTreatment time處理時(shí)間處理時(shí)間 ENSACOTM 260 Knapsack SuperTM S SuperTM P Denka200 nm200 nmSUPERTM PTIMREX KS45 mmLiCoO2 positive electrode正極Graphite negative electrode石墨負(fù)極5 mmSUPERTM P/TIMREX KS6 (1:

30、4) conductive matrix/1:4的SUPERP/KS6Hong et. al. have suggested binary 1:1 mixtures / Hong 等建議1:1的混合(Journal of Power Sources, 111 (2002) 90-96.)LiCoO2 positive electrode正極Graphite negative electrode負(fù)極Capacity retention during cycling循環(huán)過程中的能量保持0204060801000100200300400 Specific charge mAh g-1Cycle Nu

31、mber no additive 8 % KS6/2 % Super P 4 % KS6/1 % Super P02040608010004080120160200 3 % Super P/2 % KS4 5 % Super PSpecific charge mAh g-1Cycle numberGraphite and carbon black are complementary products石墨和碳黑是相互補(bǔ)充的產(chǎn)品Cell parameters電池參數(shù)電池參數(shù)Carbon black碳黑碳黑Graphite石墨石墨Electric electrode conductivity電極導(dǎo)電Particle-particle contact and contact to collector顆粒和顆粒,以及和集流器的接觸Conductive paths thorugh electrode通過電極的導(dǎo)電途徑Ionic electrode conductivity離子電極導(dǎo)電Electrolyte absorption電解液吸收Porosity control孔的控制Cycling stability循環(huán)穩(wěn)定性Flexible network適應(yīng)性的網(wǎng)絡(luò)Optimal