有机硅电解液：安全性和高电压性能研究进展.ppt

1、有机硅电解液：安全性和高电压性,能研究进展,1、Background, Safety issues related with Li-ion Batteries Safe electrolytes for high-voltage batteries,2、Organosilicon based electrolytes High-voltage OS-based electrolytes OS-based electrolytes for Si anodes 4、Summary,Outline,Safety issues of LIBs: High flammability of carbona

2、te electrolytes!,LiFePO4 battery Not safe enough！,Safety of Lithium-Ion Batteries Safety (abuse tolerance): When overcharged, thermal runaway leads to fires etc. Runaway reaction caused by release of oxygen from cathode materials (e.g., LiCoO2).,The development of new,Safe electrolyte materials!,O,O

3、,O,R,R,DMC: R=CH3 DEC: R=CH2CH3,O,O,EC O,Es= Qcapacity * Vvoltage,1. Safety! 2. High-voltage Stability!,J. Power Sources, 237 (2013) 229.,High-voltage cathodes require compatible electrolytes Electrolyte Challenges:,N,S,Additives,Dinitriles,Ionic liquids,Sulfone,Fluorinated solvent,Inorganic compoun

4、ds,Sulfonate esters,Carboxyl anhydrides,Phosphides,C,C,N,N,n,O,F C,O O,O,O O,CF3 F F,CF3,R4,N+,R2,O C F,R1 O F,R1 N+ R2 O - C F F F,R1 N+ R2 R3 O S F,O,O,S S,O O,O O,S O,O,O,O,S O,O,O,O,S O,O,S,O,CF3,CF3,F3C,F3C,F3C,CF3,O,P O,O,O O,O B O,O O,O O,Li,B,O O,O O,F F,Li,Electrolyte solvents and additives

5、 for high-voltage Solvents,LiBOB,LiODFB,C,N,H H C,n C N,LiNi0.5Mn1.5O4/Li, 3.5-4.9V, 1/12 C J Electrochem Soc, 156 (2009)A60.; 159 (2012)A370; 160 (2013)A838. J Power Sources, 189 (2009) 576.,Aprotic aliphatic dinitrile solvents n=3ADN, n=5 PMN n=6 SUN, n=8 SEN,Advantages: Electrochemical window (7-

6、8V) Flash point (110 , 163 forADN) Dielectric constant (20-30, 55 for SCN) Disadvantages: Poor compatibility with graphite Poor solubility of LiPF6 LiTFSI (V 4.3 V, corrodes collector) LiBF4 (inferior ability, poor low temperature performance),J Electrochem Soc, 149 (2002)A920; J Phys Chem B, 115 (2

7、011) 12120.,Electrochem Commun, 11 (2009) 1418; 11 (2009) 1073.,Sulfone-Based Electrolytes Advantages: High oxidation potential Low flammable High melting point; Poor compatibility with graphite; Wetting problem with separator,Li4Ti5O12/1M LiPF6FEC/DMC/D2 3/4/3/ LiNi0.5Mn1.5O4 (Data from ANL, USA),O

8、 F,Rf1,Rf2,O D2,O FEC,1 C at 55,oC,Fluorinated Based Electrolytes,Advantages: High oxidative stability High flash point/low flammability (Safe) Compatible with graphite O,Disadvantages: Bad performance at elevated temperatures (FEC) Harsh synthesis conditions/high cost,1M LiPF6 EC/DEC (3/7) 1M LiPF6

9、 EC/DMC/MFA (3/3/4),F O H C C O CH3,F MFA 1M LiPF6 MFA,LiCo2/ Graphite cell (1 Ah cell); Daikin data (Japan),Fluorinated Based Electrolytes,Energy Electrochem Commun, 10 (2008) 783.,High, Low flammability High oxidation resistance High viscosity (low conductivity 225 (2013) 113; 233 (2013) 115.,Mix

10、with carbonate or other co-solvent performance ,Ionic Liquid Electrolytes thermal stability, Very low rotation barrier around Si-O axis, (ca. 0.8 KJ/mol) low linear isation energy of the Si-O-Si angle (1.3 kJ/mol).,Organosilicon (OS) Electrolytes: High ionic conductivity, Non-flammability: Biocompat

11、ible Excellent wetting capability, Wide liquid phase range (-40200 oC) Low viscosity- comparable with alkylcarbonates Medium wide electrochemical,window Very low glass transition temperature good thermal stability,Alternative: Organosilicon Electrolytes,O,O,O,O,O,R2,R2,R1R1= H, CH3,R2= CH3, CH3CH2,C

12、arbonate electrolytes Highly flammable! O,J. Mater. Chem., 2008, 18(31), 3713-17; 2010, 20, 8224-26. Chem. Mater. , 2007, 19, 5734-5741.,Implant neuro- stimulator micro cell (27.5 3.2 mm2, 1g),Organosilicon as Safe Electrolytes 1. Excellent cyclability；2. Electrochemically stable 3. Nonflammable/Saf

13、e; 4. Environmental benign,Conventional electrolytes OS electrolytes,MCMB/LiNi0.8Co0.15Al0.05O2, 0.8M LiBOB OS electrolytes,C/5, 3.0 to 4.0 V; 100% efficiency,J Power Sources, 228 (2013) 32; 196 (2011) 2255,Electrochem Commun, 8 (2006) 429; Chem Commun, 49 (2013) 1190,Progress on Organosilicon Elect

14、rolytes (Lit.), Ionic conductivity Compatibility with graphite Oxidation potential ( 4.2 V ),Challenges of OS electrolytes:,NCH2CH2CH2C Si O CH2CH2O CH3,n,CNCH2CH2Si(CH3)(3-m)(OCH2CH2OCH3)m,CH3 dielectric constant oxidation potential ,Increased dielectric constant,Increased oxidation potential,High

15、conductivity,Organosilicon Compounds with Nitrile Group CH3,Discharge Capacity (mAh/g),Efficiency (%),Potenial / V,Specific Capacity / mAhg,-1,Specific capacity/ mAhg-1,Capacity retention (%),Specific capacity/ mAhg,0,140 120 100 80 60,105 100 95 90 85 80 300,0.7C CC to 4.4V, 0.5C DC to 3.0 V 274 cy

16、cles : 85.2 % LCO/OS co-solvent/Graphite 50 100 150 200 250,Cycle number,0,160 140 120 100 80 60 40 20,180,LCO/graphite, 2.7-4.4V, 0.2C BNS / 0.4 M LiODFB+0.6 M LiPF6 TNS / 0.4 M LiODFB+0.6 M LiPF6 SN1 / 0.4 M LiODFB+0.6 M LiPF6 40 80 120 160,0,5,25,30,0,30,90 60,120,180 150,10 15 20 Cycle number,0,

17、20,40,60,100 80,0.2 C,2C,1.5 C,1C,0.5 C,0.2 C,Miscible well with carbonate Enhanced high rate performance,0,100 200 300 400 500,600,0.0,1.0 0.5,1.5,2.5 2.0,-1,1M LiPF6 in SN1 1M LiPF6 in BNS/PC (4:6 in vol.) 1M LiPF6 in TNS,As EO arm increase,More compatibility with graphite.,Organosilicon Compounds

18、 with Nitrile Group 3.0,Cycle number J. Power Sources, 254, 29-32 (2014),Coulombic Efficiency / %,Specific capacity/ mAhg,-1,0,20,40,60,80,100,0,80 40,160 120,Cycle number,80,81,97,100 99 98,Retention: 90.4%100 cycles CE 99.5% LCO/graphite, 3.0-4.4 V,0.5C, 143 mAhg,-1,Comparison with Commercial High

19、-Voltage Electrolytes Our high-voltage OS electrolyte (OS Ionic Liquids) 101,Enhanced physical properties,Fluorination,Fluorinated OS Compounds with Oligo (EO),1S3M2, J. Mater. Chem., 2010, 20, 8224; F2MSEO2M unpublished data.,-1,dQ/dV,Cap. mAh/g,Specific capacity/ mAhg,Coulombic efficiency / %,Pote

20、ntial (V vs. Li+/Li),F2MSEO2M / 1M LiPF6+0.2MLiODFB,0,20,40,60,80,40,160 120 80,200,240,Cycle number,4.4V LCO/Li, 0.2C,80 100,95 90 85,100,90.8% 95.8% 4.5V,0.0,0.1 0.2 0.3 0.4,0.5,Graphite/Li, 0.01-3.0 V,1 M LiPF6 PC:DMC:DEC: F2MSEO2M (28:35:35:2 vol.),Unpublished data,Fluorinated OS Compounds with

21、Oligo (EO) Good compatibility with,10,20 Cycle #,30,40,320 280,graphite! 400 360,High voltage performances: LCO/C cell, 94 cycles 4.4V: 96% capacity retention 4.5V: 90% capacity retention,Specific capacity (mAh/g),Current (),Efficiency (%),Potential ( V vs. Li /Li ),0,20,40,60,80,100,60,80,120 100,1

22、80 160 140,200,Cycle number,0,40 20,80 60,100,LCO / TMOSC3GC / graphite 2.7-4.4 V, C/10,Highly polar,group,Dielectric constant ,Concentration of Li+,-1,0,1,2,3,4,5,+,TMOSC3GC TEOSC3GC DSC3GC,O,O,O,O Si,O O,Si,O,Si,O,O,O O,Wang JL, et al., 2013, to be submitted,Carbonate Functionalized Trialkoxysilan

23、es,(RO)3Si(CH2)nO,O,O,O,R= CH3O, CH3CH2O; n= 0,2,3 O,Dielectric constant as high as 37.8! 220,Current / A,3.0,3.5,4.0,4.5,5.0,5.5,6.0,320 240 160 80 0,Voltage / V vs. Li/Li,+,commerical carbonate electrolyte commerical carbonate electrolyte + 30% SN1 W.E. platinum C.E. lithium R.E. lithium Scan rate

24、: 10 mv/s,(a),OS based electrolytes for 4.4V LCO/graphite cell,commercial carbonate electrolyte: GT303 (LB303) commercial carbonate electrolyte + 30% SN1 : GT303+30%SN1,-1,Specific capacity/ mAhg,0,30,60,90,120,150,120 100 80,commercial carbonate electrolyte commercial carbonate electrolyte+30% SN1

25、LCO/graphite, 3.0-4.4V 0.5C,Cycle number commercial carbonate electrolyte: GT303+ 2%wt. VC+ 2%wt.PS commercial carbonate electrolyte + 30% SN1 : 70% TC 4.35+ 30% SN1,0.1 M LiODFB + 1 M LiPF6, 2%wt. VC+ 2%wt.PS,OS based electrolytes for 4.4V LCO/graphite cell (b) 160 140,-1,Specific capacity/ mAhg,0,

26、10,20,30,40,50,60,100,0.2C,0.5C 0.7C 1C 1.5C commerical carbonate electrolyte,commerical carbonate electrolyte+30% SN1,0.2C,(c) 160 140 120,Cycle number commercial carbonate electrolyte: GT303+ 2%wt. VC+ 2%wt.PS commercial carbonate electrolyte + 30% SN1 : 70% TC 4.35+ 30% SN1,0.1 M LiODFB + 1 M LiP

27、F6, 2%wt. VC+ 2%wt.PS,OS based electrolytes for 4.4V LCO/graphite cell,Electrochemical windows Imidazolium ILs: ca. 4V Tertraalkylammonium ILs: ca. 6V,R = (CH3)3SiCH2, (CH3)3CCH2 A = N(CF3SO2)2, BF4 J. Phys.Chem. B, 109, 21576(2005); 111, 4819 (2007); 111, 4885(2007); Talanta, 71, 68(2007).,N + N R

28、- A,+,Si N,N C4H9 - PF6, TertraalkylPhosphonium ILs: excellent thermal stability Electrochim. Acta, 51, 5567(2006),Organosilicon Based Ionic Liquids Advantages Over Carbon Analogues Weake Intermolecular interactions Lower viscosity Low glass transition temperature Hydrophobic,X = N, P; n = 1, 3; R1=

29、CH3, CH3CH2; R2=Alkyl, alkoxy A = BF4, PF6, TFSI, BOB, NCN2,R2 R2 Si R2,(CH2)nXR1(OCH2CH3)2 - A,O,O,O,O,O,O,O,F3C S N S CF3 O O TFSI,B O O BOB,Anion structures:,US 2010029970 A1; WO 2009045609 A1; CHN Pat: CN201010265833.2,Organosilicon Based Ionic Liquids,Mass Retaintion (%),Current (),OS Ionic Liq

30、uid SN1IL-TFSI AN1IL-TFSI CETMA-TFSI, mS/cm 1.35 4.29 1.10, cp 125.4 36.0 -,Tdec oC 362 325 329,Eanodic V 0.00 0.65 1.30,Ecathodic V 5.39 5.30 5.78,Novel Organosilicon Based Ionic Liquids,0,1,2,5,6,3 4 Potential (V),SN1IL-TFSI AN1IL-TFSI CEN1IL-TFSI,0,100,500,600,120 100 80 60 40 20 0,SN1IL-TFSI AN1

31、IL-TFSI CEETMAIL-TFSI,200 300 400 o Temperature ( C),Capacity (mAh/g),Capacity (mAh/g),Efficiency (%),Efficiency (%),0,0,30,150 120 90 60,180,0 10 20 30 40 50 60 70 80 90 Cycle,20,80 60 40,100,0,5,25,30,0,30,150 120 90 60,180,0.2C,2C,1.5C,1C,0.5C,10 15 20 Cycle number,0.2C,0,20,80 60 40,100,120,Cell

32、 Performances for Novel OS Ionic Liquids LCO/Graphite, 2.7-4.4 V, 0.2C SN1IL-TFSI:DMC =1:1 by vol. 210,Capacity (mAh/g),Efficiency (%),Capacity (mAh/g),Efficiency (%),0,10,20,30,40,50,60,70,80,90,100,220 200 180 160 140 120 100 80 60 40 20 0,Cycle Number,100 80 60 40 20 0,NMC-LI cell; Capacity Reten

33、tion: 96% (100 cycle) SN1IL-TFSI-EMC-1-1,0,2,4,6,220 200 180 160 140 120 100 80 60 40 20 0,8 10 12 14 16 18 20 22 24 26 28 30 Cycle Number,100 80 60 40 20 0,NMC/graphite (2.7-4.6V) SN1IL-TFSI-EMC-1-1,Cell Performances for Novel OS Ionic Liquids,Coulombic efficiency / %,Specific capacity/ mAhg,-1,0,5

34、,10,15,20,25,30,35,0,80 40,200 160 120,0,40 20,Cycle number,28,Graphite/NMC, 2.7-4.5 V, 0.2C 2%PS 0.2M LiODFB 0.8 M LiPF6 BNS,BNS for 4.5 V graphite/NMC cell Provided by YTQ 100 80 60,Specific capacity/ mAhg,-1,Efficiency (%),0,5,10,15,20,25,0,Cycle number,(a) 210 180 150 120 90 60 30,0,100 80 60 40

35、 20,SN1IL-TFSI for 4.5 and 4.6 V graphite/NMC,2.7-4.6 V 2.7-4.5 V Graphite/NMC0.2C SN1IL-TFSI/EMC (1:1 by vol.),Capacity/mAh,14000 12000 10000 8000 6000 4000 2000 0,0,100,200,300,400,500,600,700,E12A084-1 668 Cycle； 83.53% EST: 811 Cycle； 80%,10A AE7365270PM3HSE) -11500mAh,Commercialization of OS El

36、ectrolytes NMC/OS Electrolyte/C Battery (10 Ah),Number of Cycle Charge: CC 10Ato 4.2V; CV 4.2V to 3.5hr or 200mAcut- off at RT Discharge: 10A to 2.75V at RT,采,测 一,1s采集一 个数据,两种电解液的电池在穿刺测试过程 中温升趋势和最高温度均没有明显差异， 即电池内部的放热反应方式和程度没有 变化，但有机硅电解液能有效抑制易燃 成分的燃烧。,有机硅电解液与商业电解液三元动力电池（10 Ah) 针刺安全性对比 有机硅电解液电池烟雾喷射力度较

37、小，地上的黑色物质少,商业电解液电池烟雾喷射力度较大，地上的黑色物质多，部分电池 会着火爆炸,OS electrolyte battery Pack (10.8V，100Ah),Demonstration of OS Battery Pack Application: Solar Energy Navigation light Collaboration：GD Maritime Safety Administration (广州航标局）,SiC composite,Compatability of OS Electrolyte with Si Anode,Discharge capacity

38、(mAh/g),Capacity retention (%),Columbic efficiency (%),Electrolyte,LB303,LB303+FEC,LB303+ BNS,Electrode 1st CE 1st reversible cap. 100th CE 100th reversible cap. Capacity retention,Si 77.1% 2706 98.8% 136 5.0%,SiC 79.7% 1054 98.4% 495 46.9%,Si 86.4% 3089 98.7% 1288 41.7%,SiC 84.2% 1075 96.0% 841 78.

39、2%,Si 86.1% 3348 99.4% 2035 60.8%,SiC 82.0% 1139 96.9% 1003 88.1%,Current density: 400mA/g,0,20,80,100,0,1000,8000 7000 6000 5000 4000 3000 2000,Si anode (LB303) Si anode (LB303+FEC) Si anode (LB303+BNS) SiC anode (LB303) SiC anode (LB303+FEC) SiC anode (LB303+BNS),40 60 Cycle number,100 80 60,0,20,

40、40,60,80,100,100 80 60 40 20 0,120,Si anode (LB303+BNS) SiC anode (LB303) SiC anode (LB303+FEC) SiC anode (LB303+BNS),Cycle number Si anode (LB303) Si anode (LB303+FEC),Discharge capacity (mAh/g),Discharge capacity (mAh/g),Columbic efficiency (%),Columbic efficiency (%),Current density: 400mA/g,68%

41、capacity retention,0,50,100,150,200,1000 0,2000,4000 3000,SiC (LB303) SiC (LB303+FEC),SiC (LB303+BNS),20 0,40,60,100 80,LB303+BNS Si 85.9% 2621 99.7% 1696,Cycle number Current density: 600mA/g Electrolyte Electrode 1st CE 1st reversible capacity 200th CE 200th reversible capacity,0,50,200,1000 0,200

42、0,3000,4000,6000 5000,Si anode (LB303+BNS) 100 150,Cycle number,Current density: 600mA/g,60 50,70,80,100 90,SiC,Si,纳米硅颗粒负极材料极片在商业电解液和使用了FEC添加剂时，极片在首次嵌脱 锂后电极出现明显的脱落，在使用了有机硅电解质（BNS）为添加剂时，极片脱 落现象明显改善。与裸硅负极材料相比，经过碳包覆后制备出的碳硅复合材料极,片在使用商业电解液时，经过嵌脱锂后有部分剥落，但情况比裸硅电极已有改善。,当使用了FEC和BNS为添加剂时有明显的改善，极片并为出现类似的剥落现象。,

43、Intensity (a.u.),Intensity (a.u.),Intensity (a.u.),Raman shift (cm ),Raman shift (cm ),Raman shift (cm ),Raman data,Ref: 1 Adv. Mater. 2013, 25, 44984503 2 J. Non-Cryst. Solids 2006 , 352 , 4101 .,1、BNS作为添加剂易于在Si表面形成含有Si-,O-Si的SEI膜 2、与传统 的SEI膜不同，形成的这种SEI膜 可能有一定的脱嵌锂活性(Li2Si2O5) 3、在脱锂后，BNS作为添加剂时产生的SEI

44、 膜较其它两种电解液相比能稳定存在,500,1000,1500,Si,LB303,LB303+FEC LB303+BNS,-1,Delithiation at 1.5V,500,1000,1500,2000,Si befor cycle,500,1000,1500,Si-Si stretching,LB303 LB303+FEC LB303+BNS,-1,Si-O-Si bending,in Li2Si2O5,-1 Lithiation at 0.01V Si-O stretching vibration,Si,Intensity (a.u.),Intensity (a.u.),Intensi

45、ty (a.u.),Raman shift (cm ),Raman shift (cm ),Raman shift (cm ),500,1000,1500,2000,SiC,LB303,LB303+FEC LB303+BNS,Si-O-Si bending,Lithiation at 0.01V Si-O stretching vibration in Li2Si2O5,-1,500,1000 1500,2000,SiC,Delithiation at 1.5V,LB303 LB303+FEC LB303+BNS,G band,D band,-1,1、BNS作为添加剂在SiC表面,形成含有Si

46、-O-Si的SEI膜 2、由于有包覆碳层的存在，以 FEC和BNS作为添加剂时产生的 SEI膜都较稳 Ref: 1Adv. Mater. 2013, 25, 44984503 2 J. Non-Cryst. Solids 2006 , 352 , 4101 .,500,1000 1500,2000,SiC anode before cycle,-1,Intensity (a.u.),Intensity (a.u.),1.5,2.0,2.5,LB303+BNS(Lithiation) LB303+BNS(Delithiation),LB303(Delithiation),Kev,O,C,LB30

47、3(Lithiation) F,Si,Si anode,0.5,1.0,2.0,2.5,LB303+BNS(Delithiation),LB303+BNS(Lithiation),LB303(Delithiation) LB303(Lithiation),SiC anode,Si,F,O,C,1.5 Kev,0.5 1.0 Si 元素含量分析,1、LB303和LB303+FEC: Si电极在循环后表面硅含量猛增，SEI膜的破坏硅的裸露 2、 BNS作为添加剂时产生的SEI膜中Si含量高于LB303形成的，证明Si成分参与成膜 3、在SiC中碳层的存在对三种电解液来说都有利形成更加稳定的SEI膜

48、,Transmission (a.u.),Transmission (a.u.),Transmission (a.u.),500,2500,Delithiation,1000 1500 2000 Wavenumber (cm-1),Lithiation,LB303+FEC,Si anode,500,2500,Delithiation,Lithiation,LB303,Si anode,1000 1500 2000 Wavenumber (cm-1),*,1、 (LB303) 870：LiPF6峰的相对强度明显减小，说明 经过脱锂后SEI的分解 （Ref: J. Phy. Chem. C 201

49、1, 28, 965-976） 2、(LB303+FEC) 870：LiPF6 1640, 1450,1090, 1810: 为FEC分解产物 （Ref: Langmuir 2011, 28, 965-976）,500,1000,1500,2000,2500,*,Si anode,LB303+BNS Delithiation Lithiation,Wavenumber (cm-1),3、(LB303+BNS) 870：LiPF6峰的相对强度减小不明显，说 明经过生成的SEI较为稳定，对比三种电解液，1060处的 Si-O-Si 键明显增强，证实了SEI膜中的Si-O-Si成分，脱锂 后任然能够

50、稳定存在,Transmission (a.u.),Transmission (a.u.),Transmission (a.u.),SiC anode,500,2500,LB303+FEC Lithiation Delithiation,SiC anode,1000 1500 2000 Wavenumber (cm-1),500,1000,1500,2000,2500,Delithiation Lithiation,Wavenumber (cm-1),500 1000 1500 2000 2500,SiC anode,LB303 Delithiation Lithiation,Wavenumbe

51、r (cm-1) LB303+BNS,1、 SEI结构分析参考Si anode 2、 与Si电极不同，由于C的存在，形成 的SEI膜更加稳定(870：LiPF6峰的相对 强度在脱锂后变化没有Si电极那么明显）,Si anode (Electrolyte:LB303),发生膨胀 Lithiation at 0.01V,发生收缩开裂 Delithiation at 1.5V,生成的SEI膜 生成的SEI膜碎裂,Si anode (Electrolyte: LB303+ 10% BNS),较小膨胀 Lithiation at 0.01V,并未发生收缩开裂 Delithiation at 1.5V,生成的SEI膜 生成的SEI膜稳定存在,SiC anode (Electrolyte:LB303),发生一定的膨胀 Lithiation at 0.01V,发生收缩 Delithiation at 1.5V,生成的SEI膜 生成的SEI