Lithium isotopic systematics of hydrothermal vent fluids at the
Main Endeavour Field,Northern Juan de Fuca Ridge
D.I.Foustoukos a,*,R.H.James b ,M.
E.Berndt c ,W.E.Seyfried,Jr.a
a
Department of Geology and Geophysics,University of Minnesota,Minneapolis,MN 55455,USA
b
Department of Earth Sciences,The Open University,Milton Keynes MK76AA,UK
c
Minnesota Department of Natural Resources,Division of Lands and Minerals,St.Paul,MN 55155,USA
Received 1February 2004;received in revised form 1July 2004
Abstract
Vent fluids issuing from the Main Endeavour Field (MEF),Juan de Fuca Ridge,were analyzed for d 7Li to help constrain subseafloor hydrothermal alteration and phase separation processes.Magmatic activity prior to sampling of the fluids in 1999enhanced heat and mass transfer,as indicated by the large scale,but temporary,changes in vent fluid chemistry.In particular,dissolved chloride concentrations indicate formation of supercritical Cl-poor vapors,which affected alteration throughout the MEF system.d 7Li of fluids,however,ranges from +7.2to +8.9x and reveals no significant correlation with dissolved chloride,being consistent with results of hydrothermal experiments that show no lithium isotope fractionation during supercritical phase separation.On a chloride-normalized basis,Li concentration data indicate relatively short residence times or high fluid/rock mass ratios of vent fluids most impacted by phase separation effects.Reaction path models involving Li isotope data also show elevated fluid/rock mass ratios.Boron data,in contrast,suggest direct input from degassing magma.Enhanced heat flow associated with magmatic injection at depth inhibits penetration of seawater-derived hydrothermal fluid into fresh basalt,particularly in those systems where magmatic volatile input is most active.The inverse correlation between Li/Cl and B/Cl in vapor-rich vent fluids may be a useful indicator of recent subseafloor magmatic activity.D 2004Elsevier B.V .All rights reserved.
Keywords:Lithium isotopes;Juan de Fuca Ridge;submarine hydrothermal systems;phase separation;hydrothermal alteration
1.Introduction
It is widely accepted that the chemical evolution of subseafloor hydrothermal systems at mid-ocean ridges is affected by phase separation processes that
introduce large variations in the dissolved chloride composition of vent fluids (Butterfield et al.,1994;V on Damm et al.,1997,2000,2003),which in turn influence a wide range of homogeneous and hetero-geneous equilibria.Near-seafloor magmatic intru-sions,or diking events,are particularly effective in triggering subcritical and supercritical phase separa-tion in the NaCl–H 2O system (Lilley et al.,2003;
0009-2541/$-see front matter D 2004Elsevier B.V .All rights reserved.doi:10.1016/j.chemgeo.2004.08.003
*Corresponding author.
E-mail address:fous0009@https://www.doczj.com/doc/be331118.html, (D.I.Foustoukos).
Chemical Geology 212(2004)17–
26
https://www.doczj.com/doc/be331118.html,/locate/chemgeo
Seyfried et al.,2003;V on Damm et al.,1995). Indeed,the composition of vapor-rich fluids sampled immediately following magmatic events can provide important clues as to the range of physicochemical conditions governing hydrothermal alteration and mineralization in subseafloor reaction zones(See-wald et al.,2003;Seyfried et al.,2003;V on Damm et al.,1997,2000).Br/Cl ratios,dissolved gas concentrations and hydrogen isotope systematics of vapor-rich vent fluids have helped to differentiate supercritical from subcritical phase separation,as well as whether or not phase separation occurs under closed-system or open-system conditions(Berndt et al.,1996;Berndt and Seyfried,1990,1997;Oosting and V on Damm,1996;Seewald et al.,2003;Seyfried et al.,2003).
Highly mobile trace elements(e.g.B,Li)are also potentially valuable aides for assessing alteration processes occurring in the root zones of submarine hydrothermal systems(Chan et al.,1993;Seyfried et al.,1984,1998;Spivack and Edmond,1987).For example,during seawater interaction with fresh basalt, Li and B effectively partition into the fluid,especially at elevated pressures and temperatures(Chan et al., 1993;Seyfried et al.,1984;Spivack and Edmond, 1987).For Li,experiments have shown that at4008C, approximately70%of the Li initially in fresh basalt partitions into the aqueous phase at a fluid/rock mass ratio of near unity(Seyfried et al.,1984).In keeping with these data,the Li composition of basalts recovered from the sheeted dike complex at ODP Hole504B(Chan et al.,1992,2002),which have been altered at~250to4008C,confirms extensive,but not quantitative leaching of Li from the rock.These rocks are isotopically light,supporting retention of6Li in the alteration products(James et al.,2003;Seyfried et al., 1998).
Here we report Li,B,and Li isotopic composi-tions of vent fluids from the high-temperature Main Endeavour Field(MEF),Juan de Fuca Ridge.These fluids were sampled approximately three months after a large earthquake swarm in June1999. Although initially interpreted as tectonic(Johnson et al.,2000),more recent data suggest that the seismic event was actually magmatic in origin and intensified phase separation processes(Lilley et al., 2003;Seyfried et al.,2003).Further investigation is needed,however,to understand better the interplay between magmatic and hydrothermal alteration pro-cesses.To advance this objective,we integrated Li and B concentrations with Li isotopic data influ-enced by the1999magmatic/seismic event.More-over,the vent fluid samples provide a unique opportunity to assess the role of supercritical phase separation effects on Li mobility and hydrothermal alteration processes.These data,together with Li isotopic composition of samples from hydrothermal experiments in the two-phase region(Berndt et al., 1996),permit assessment of the extent of Li isotope fractionation between supercritical vapors and brines coexisting with basalt and alteration phases in the hydrothermal reaction zone at MEF.
2.Geologic setting
The Main Endevour Field is located at47857V N and129805V W on the Endeavour segment of the Juan de Fuca Ridge and is situated on the axial valley floor at a depth of~2200m.The field includes numerous active and inactive hydrothermal sulphide structures that are located along active faults and fissures(Fig.1;Butterfield et al.,1994; Delaney et al.,1992,1997).High-temperature vent fluids recovered prior to the1999magmatic event by DSV Alvin(1984,1987and1988)are characterized by a relatively constant chemical composition and reveal dissolved chloride concentrations that ranged from47%to94%of seawater chloride,with dissolved chloride decreasing from northeast to southwest(Butterfield et al.,1994;Delaney et al., 1992,1997).Magmatic activity in June1999, however,resulted in large changes in vent fluid chemistry(Seyfried et al.,2003),but these seem to have been temporary;the composition of fluids recovered from Hulk and Dante vents in2000was largely similar to their pre-1999levels(Seewald et al.,2003).
3.Methods
Vent fluid samples were collected in titanium majors bottles(Edmond et al.,1979;V on Damm et al.,1995).Concentrations of dissolved Li(Table1) were determined at the Open University by induc-
D.I.Foustoukos et al./Chemical Geology212(2004)17–26 18
tively coupled plasma mass spectrometry (ICP-MS;Agilent 7500A),using an online isotope dilution technique.The analytical uncertainty for these meas-urements is better than F 2%at the 1r level.Concentrations of all other elements listed in Table 1were determined at the University of Minnesota using methods described in Seyfried et al.(2003).An aliquot of each sample containing ~40ng of Li was dried down and taken up in 100A l 0.2N thermally-distilled (TD)HCl for Li isotope analysis.This was passed through a cation exchange column to separate Li following the method described in James and Palmer (2000).Li isotope ratios were measured by both thermal ionization mass spectrometry (TIMS;James and Palmer,2000)and multicollector ICP-MS (Nu Instruments).The internal precision of TIMS analysis is usually b F 0.2x (2r )relative to the l -SVEC Li 2CO 3standard (which has 7Li/6Li=12.0836);and the external precision is F 1.0x (2r ).Multicol-lector ICP-MS analysis,however,was conducted fol-lowing different procedures.Each sample analysis consists of measurement of 20ratios,and the
back-
Fig.1.Geologic map of the Main Endeavour field,Northern Juan de Fuca Ridge.The figure was modified after by Delaney et al.(1992,1997)and Butterfield et al.(1994).
D.I.Foustoukos et al./Chemical Geology 212(2004)17–2619
ground (which is measured before each analysis)is subtracted.The sample analysis is bracketed before and after by measurement of the L-SVEC standard that has a concentration within F 1%of that of the sample.A 10ppb solution and solution uptake rate of 30A l/min typically produces a beam intensity of ~1V compared with a background of 3mV .The
internal precision on 7Li/6Li measurements is usually b F 0.2x (2r ),and the external precision of this technique,determined by 47analyses of 16separate preparations of seawater over 6analytical sessions,is F 0.90x (2r ).
The composition of hydrothermal end-members (Table 2)was calculated using a least squares regression of an individual chemical constituent and Mg (Mg/Li for d 7Li)by assuming passage through the seawater composition and then extrap-olating measured values to zero Mg.Extrapolation of fluid composition to zero Mg is well-established (e.g.,V on Damm and Bischoff,1987),and it allows determination of vent fluid composition prior to mixing with seawater in the sampler dead volume and seawater entrained during collection.In all cases,regression coefficients were better than 0.97.Uncertainties estimated for the end-members are less than 1%.
4.Results and discussion
Fluid samples were collected from the Hulk,Dante,Bastille,Sully,and Cantilever vents (Fig.1)3months after the magmatic/seismic event.With the exception of Cantilever,all of these vents had been sampled on one or more previous occasions (Butter-field et al.,1994).Vent fluid temperatures generally increased throughout the MEF in the aftermath of the reported magmatic activity (Kelley et al.,2001;Seyfried et al.,2003).Moreover,significant changes in dissolved chloride were also apparent in compa-
Table 2
End-member concentrations of Li and B and Li isotopic composition of MEF vent fluids Vent site T (8C)a Cl
(A mol/kg)a Li
(A mol/kg)Li/Cl
(A mol/mmol)d 7Li (%)Li b
(A mol/kg)B
(A mol/kg)a B/Cl
(A mol/mmol)Hulk 3474264110.967.9F 0.8521810 1.90Dante 3504183840.927.2F 0.7497825 1.97Bastille 3682081530.747.9F 2.0399800 3.85Cantilever 37532200.648.9F 2.634696030.00Sully 37939300.767.6F 0.8410
98025.13Seawater
25
541c
26c
0.05
32.5F 1.0
420
0.78
d 7Li for seawater based on James and Palmer (2000).
a
Seyfried et al.(2003).b
Li normalized to seawater chloride.c
V on Damm et al.(1985).
Table 1
Concentrations of selected constituents in MEF vent fluids Samples
Mg (mmol/kg)a Cl (mmol/kg)a
Li (A mol/kg)d 7Li (x )
TIMS MC-ICP-MS
Hulk M3468A 32.248417411.49.2M3468B 9.04383427.0M3468C 1.54234018.49.0M3468D 2.4433396BGT3478
2.8
447
388
7.4
9.0
Dante
M3470A 13.34462928.3M3470B 14.9457284
7.3
7.5
Bastille
BGT3470 5.82391398.5M3470C 36.64386812.212.3M3470D 29.039884
13.5
14.2
Cantilever
BGT3474 2.454218.6M3474A 8.11092115.4
Sully
M3474B 2.562298.6BGT348052.9
534
27
32.5
a
Seyfried et al.(2003).
D.I.Foustoukos et al./Chemical Geology 212(2004)17–26
20
rison with previous data(32à426mmol/kg,compared with255à505mmol/kg prior to1999;Butterfield et al.,1994;Seyfried et al.,2003).Modeling of phase equilibria in the NaCl-H2O system at MEF(Seyfried et al.,2003)suggests that the Cantilever and Sully vents fluids were strongly affected by the formation of a supercritical vapor,while vent fluids at Hulk,Dante, and Bastille were affected more by mixing of super-critical vapors and evolved hydrothermal seawater,as suggested earlier by Butterfield et al.(1994).
4.1.Lithium systematics and heat fluxes at MEF
Dissolved Li concentrations in the1999end-member vent fluids at MEF range from20A mol/kg to411A mol/kg(Table2),as measured for the vapor and more near seawater chloride samples respectively. In order to better distinguish the effects of phase separation from rock–fluid interaction processes,Li/ Cl ratios were calculated.These ratios reveal values significantly greater than for seawater(Table2), underscoring the importance of water–rock interaction in the subseafloor reaction zone,where phase sepa-ration and mixing processes occur.Although there is some evidence for a sedimentary component in MEF vent fluids(Lilley et al.,1993),enhanced basalt-derived sources are indicated following the1999 seismic event(Seyfried et al.,2003).
Li/Cl ratios of the vapor-dominated fluids at Cantilever and Sully are distinctly lower than at Hulk and Dante,which have more moderate Cl concen-trations,exhibiting a pattern commonly observed in mid-ocean ridge hydrothermal systems(Fig.2a; Seyfried and Shanks,in press).The variability of Li/ Cl ratios across the MEF,however,can be explained based on the intensity and proximity of heat sources affecting the convective circulation of seawater in the subseafloor reaction zone.For example,in the case of heat transfer from a magmatic intrusion,conduction across a thin impermeable boundary layer(Cann et al.,
1986)likely inhibits penetration of seawater,limiting the availability of rock-derived Li and producing elevated fluid/rock ratios.Fueling a hydrothermal system by cooling of hot rock(Lister,1982,1995),in contrast,forms a cracking front and provides rela-tively continuous access to the rock and coexisting trace incompatible elements,resulting in the decrease of fluid/rock ratios,as expressed by relatively high concentrations of Li and B.Therefore,trace incom-patible elements can provide important constraints on rock–fluid interaction processes in subseafloor reac-tion zones.For example,low Li/Cl at low Cl trending to the higher Li/Cl at higher Cl concentration from south to north across the MEF(Fig.2a)implies less reaction with rock(more conduction across steeper thermal gradients)in the hotter zone and
more Fig.2.Li/Cl and B/Cl ratios for vent fluids emitted from MEF.The trends of Li/Cl(a)and B/Cl(b)ratios indicate different mechanisms controlling elemental partitioning in the hydrothermal fluids.The relatively low Li/Cl ratios observed at Cantilever and Sully suggest high fluid/rock ratios induced by heat extraction associated with magmatic intrusion.The elevated Li/Cl ratio at Hulk,however,is likely generated by low fluid/rock ratios associated with propaga-tion of fluid into hot rock.In contrast,the high B/Cl ratios in the vapor-rich fluids suggest magmatic degassing(see text).
D.I.Foustoukos et al./Chemical Geology212(2004)17–2621
reaction(extraction of mobile elements and heat)in the other cooler portions of the system.The vapor-rich fluids from Sully and Cantilever,however,are unusually enriched in dissolved B,and have high B/ Cl ratios(Table2;Fig.2b),implying abundance of fresh rock relative to the mass of circulating seawater. This inference is distinctly opposite that based on Li/ Cl,which suggests limited access to fresh rock.We interpret this to indicate an alternative source of B, most likely involving direct magmatic input,as is the case of CO2and He(Lilley et al.,2003;Seyfried et al.,2003).Indeed,magmatic degassing effects involv-ing boron have been observed in basalt-hosted geo-thermal systems(Arnorsson and Andresdottir,1995) and basaltic lava flows(Nakamura).Thus,one interpretation for the combined(Li,B)trace element data could involve magma injection,extensive heating effects that constrain access to fresh rock,and mass transfer of boron from the magma to the overlying hydrothermal system.
Mass and heat transfer across an impermeable layer,however,might not be the only mechanism controlling Li and B fluxes at MEF.Phase separation-induced fractionation could affect differentially the partitioning of Li and B in the vapor and brine phases. For example,fluid inclusion microanalyses suggest that phase separation processes result in strong partitioning of B and Li in magmatic vapors and brines,respectively(Audetat et al.,1998).Conse-quently,elevated B/Cl and low Li/Cl ratios could be expected for the supercritical MEF vapors,while mixing of vapors with a brine pool could give rise to more Li enriched and B depleted saline fluids(e.g., Hulk,Dante).The fractionation patterns needed to support this alternative model,however,are not consistent with results of hydrothermal experiments conducted within the two-phase region of seawater (Berndt et al.,1996:Table3);Berndt and Seyfried, 1990;Bischoff and Rosenbauer,1987).Indeed,results indicate that Li and B partition slightly into the vapor and brine phase respectively,in good agreement with the B and Li(chloride-normalized)composition of hydrothermal fluids issuing from the phase-separated Brandon vent at the East Pacific Rise(V on Damm et al.,2003).This partitioning behavior may not be the case at all P–T conditions,however,especially when the bulk composition shifts significantly from sea-water values.Thus,additional experimental and field data are needed before B,Li fractionation during phase separation can be entirely ruled out to account for chemical trends at MEF and related vent systems.
Lithium isotopic composition of the MEF vent fluids ranges from+7.2to+8.9x,falling within the range of values reported for other submarine hydro-thermal systems(Chan et al.,1993,1994).These values are higher than those for unaltered basalt(+3.4 to+4.7x;Chan et al.,1992),which is consistent with preferential uptake of6Li into secondary mineral phases.Although fractionation of Li isotopes during secondary mineral formation decreases with increas-ing temperature,the fractionation factor(a min–sol)is slightly lower than unity(~0.996)at fluid temper-atures applicable to the MEF system(347–3798C; Chan et al.,1994;James et al.,1999,2003).
Although the d7Li composition of the MEF hot spring fluids is clearly influenced by rock–fluid interaction in subseafloor reaction zones,other effects involving partitioning of Li and Li isotopes between vapors and brines may be important as well.As illustrated in Fig.3,the d7Li signature of vent fluids issuing from Hulk and Dante fall within the same range of values measured for the vapor-rich Cantilever and Sully vent systems.These data are consistent with results of hydrothermal experiments
(homogeneous Fig.3.Lithium isotopic composition and dissolved chloride of vent fluid end-members in the aftermath of the1999magmatic event. Within the uncertainties of the data,the lack of variability of d7Li with chloride between the vapor-rich fluids at Sully/Cantilever and the more near-seawater chloride fluids at Hulk/Dante suggest that Li isotopes are not fractionated during supercritical phase separation. This inference is consistent with experimental data(see Table3).
D.I.Foustoukos et al./Chemical Geology212(2004)17–26 22
system)conducted at431–4478C and322–397bars; temperature and pressure conditions within the super-critical two-phase region of seawater(Berndt et al., 1996).During these experiments,a7Li-enriched NaCl–H2O solution was phase separated and the conjugate vapor and brine pairs were analyzed to investigate the extent of d7Li fractionation.Results reveal that the isotopic fractionation factor between vapor and brine(a vapor–brine=(1+(d7Li vapor/1000))/(1+ (d7Li brine/1000)))is near unity,as indicated by the nearly identical d7Li values for vapors and brines throughout the two-phase region investigated(Table 3).Phase separation effects therefore,cannot induce Li isotope fractionation.Rather,the d7Li value of MEF vent fluids must be linked to fluid–rock interaction in the subseafloor reaction zone.
4.2.The role of fluid/rock mass ratio
Water/rock ratios for basalt alteration at MEF can be determined from the vent fluid Li and Li isotope systematics using the model of Magenheim et al. (1995).In this model,the rock is incrementally reacted and Li is partitioned into the fluid and alteration phases.The relationship of the integrated concentrations of the two isotopes X and Y in solution with the water/rock ratio is described in the following two equations(Chan et al.,2002;Magenheim et al., 1995;Sturchio and Chan,2003):
r w ?à
1
D
ln
X ràDX
X ràDX o
e1T
r w ?à
1
a altàsol D
ln
Y ràa altàsol DY
Y ràa altàsol DY o
e2T
where X and Y are the concentrations of6Li and7Li,
respectively,in fresh rock(X r,Y r),in seawater(X o,
Y o),and in the final hydrothermal fluid normalized to
seawater salinity(X,Y).Normalizing the hydro-
thermal fluid to seawater Cl allows us to separate
basalt alteration from the effect of phase separation
(V on Damm,2000).Data involving the degree to
which basalt-leached Li partitions between the fluid
and coexisting minerals(D=Li alt/Li sol)during basalt
alteration and the fluid–mineral isotope fractionation
factor(a alt–sol)are also required.Theoretical model-
ing,however,indicates that at the high temperature of
MEF vent fluids,it is the values of D and the Li
concentration of fresh rock that are most important
controls on w/r ratios.
The Li content of fresh MORB has been exten-
sively investigated and reported for the mid-Atlantic
and East Pacific Rise(Chan and Edmond,1988;Chan
et al.,1992,1993);values of D,however,are poorly
known(Berger et al.,1988),especially at relatively
high temperatures.Thus,there is no unique solution to
Eqs.(1)and(2).For example,given an initial Li
concentration of864A mol/kg(Chan et al.,1992)and
26A mol/kg(V on Damm,1995)for fresh MORB and
seawater,respectively,with corresponding d7Li values
of+5.0x(Chan et al.,1992)and+32.5x(James and
Palmer,2000),together with MEF vent fluid-dis-
solved Li(normalized to seawater chloride)and d7Li
(Table2),water/rock ratios greater than unity are
suggested for a broad range of likely D values(0.23–
2;Fig.4).
Thus,more accurate knowledge of D values for Li
would permit more quantitative constraints to be
imposed on w/r.Although unambiguous data are not
presently available for this,we can use w/r ratios
calculated for other basalt-hosted hydrothermal sys-
Table3
Chemical composition and Li isotopic data for fluids sampled during supercritical phase separation experiments(see Berndt et al.(1996)for details of the experimental approach used to acquire vapors and coexisting brines)
Phase T(8C)P(bar)Cl(mol/kg)Li(A mol/kg)Li/Cl(A mol/mol)d7Li(%)a vapor–brine Vapor4393700.21247222591.3 1.0002 Brine439370 3.038625206591.0
Vapor4473970.29967224590.20.9995 Brine447397 3.304649196591.0
Vapor4393480.10148475592.00.9995 Brine439348 4.221869206592.8
Vapor4313220.06543662591.10.9997 Brine431322 4.168814195591.5
D.I.Foustoukos et al./Chemical Geology212(2004)17–2623
tems to estimate D for the MEF vent fluids.For example,w /r ratios estimated from the d 11B values of vent fluids issuing from 218N EPR and 138N EPR are in the range of 0.7–1.5(Spivack and Edmond,1987).Combining these data with our data for Li,together with constraints imposed by Eqs.(1)and (2),gives D values of approximately 0.5to 1(Fig.4),which are in line with those reported in experimental studies of basalt alteration by Berger et al.(1988)and James et al.(2003).These values give relatively high w /r ratios (1.7–2.5)for the low-Cl fluids (Sully,Cantilever),suggesting that the injection of magma in the near proximity of these sites results in localized heating,supercritical phase separation effects and the release of buoyant vapor-rich fluids.Heat transfer may have been sufficient to impede,if not terminate,propaga-tion and penetration of fluid into fresh basalt,giving rise to elevated w /r ratios.Studies of vent fluids recovered from 98–108N East Pacific Rise also
suggest that enhanced magmatic activity lowers the residence time of fluids in the subseafloor reaction zone (V on Damm,2000).The data from MEF indicate that Li isotopic systematics of vent fluids can potentially contribute to our understanding of the temporal evolution of subseafloor hydrothermal sys-tems.The effects of temperature,pressure,and bulk composition on trace element partitioning and isotopic fractionation,however,need to be better constrained.
5.Conclusions
Vent fluids collected from the Main Endeavour Field (MEF)on the Juan de Fuca Ridge three months after a magmatic intrusion with attendant seismic activity show evidence of phase separation processes and fluid–rock interaction in subseafloor reaction zones.Concentrations of dissolved Li are an order of magnitude greater in vents with the near-seawater chloride (Hulk and Dante)than they are in chloride-depleted,vapor-rich fluids sampled from the Cantilever and Sully sites.The d 7Li values of the vent fluids,however,are generally similar for all sites.This suggests that there is no Li isotope fractionation associated with supercritical phase separation,as has been confirmed by Li isotope analysis of vapor–brine pairs produced during phase separation experiments.
Normalizing dissolved Li concentrations to chlor-ide (Li/Cl)accounts for phase separation effects and shows that vapor-rich vent fluids have lower Li/Cl relative to vent fluids with higher Cl.These data suggest that the low-chloride vapors either formed at relatively high fluid/rock mass ratios or the residence time of the fluids in the reaction zone was sufficiently short so as to limit rock–fluid interaction.To place constraints on the fluid/rock mass ratio,Li/Cl and Li isotope data were combined with a range of values for Li partitioning between minerals and coexisting fluids (D ).These data suggest that the Cl-depleted vent fluids (Sully,Cantilever)formed at elevated fluid/rock mass ratios (1.7–2.5),whereas lower values are indicated for vents fluids having dissolved chloride more near-seawater (Hulk,Dante).Surprisingly,dissolved boron,which is also highly incompatible,suggests a relatively low fluid/rock mass ratio for the vapor-rich fluids at MEF,
as
Fig.4.Integrated w /r ratios as a function of dissolved Li*(chloride-normalized)based on d 7Li systematics for a range of fluid–mineral distribution coefficients (D ).The model was constructed assuming d 7Li in the hydrothermal end member of +8x ,which is generally consistent with the range of values measured at MEF (Table 2).Estimation of the fluid/rock mass ratios is strongly depended on the D values and chloride normalized Li concentrations in vent fluids.Lithium fluid-mineral partition coefficient data,however,can potentially be better constrained from w /r ratios established independently from B isotope systematics for vent systems at 138and 218N EPR (Spivack and Edmond,1987).Thus,assuming similar D values exist in subseafloor reactions zones at MEF (see text)fluid/rock mass ratios of between 1.25and 2.5are likely to control the subseafloor reaction zone (shaded region).Dissolved Li concentrations at 218N EPR and 138N EPR are from Chan et al.(1993).
D.I.Foustoukos et al./Chemical Geology 212(2004)17–26
24
indicted by the highly elevated B/Cl.This apparent conflict,however,can be resolved if sources of boron other than provided by rock-fluid interaction are active at MEF.We suggest that one such source of boron might be directly linked to the1999 magmatic event.The presence of recently intruded magma in the subseafloor reaction zone at MEF causes phase separation effects and ascent of buoyant vapor-rich fluids with low Li/Cl and high B/Cl ratios.Thus,the combined compositional trends of mobile trace elements(Li,B)in hydrothermal vent fluids could serve as geochemical markers of modern subseafloor magmatic activity. Acknowledgments
We thank the ALVIN Group,the captain,and the crew of the R/V Atlantis for their help and assistance while at sea.The manuscript was improved by thoughtful reviews from Martin Palmer and Shao-Yong Jiang.This work was supported through NSF grants OCE-0117117and OCE-9911471.[RR] References
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序 号 公司名称产能产量性能应用领域使用 公司1 湖南长远锂科 有限公司 500吨/ 年 LY303 克容量大于143mAh/g,压实密度 高 圆柱形电池， 铝壳电池和聚 合物电池 LY304 克容量大于145mAh/g,体积比容 量高 高容量型电池 LY305 克容量大于155mAh/g,循环性能 好 圆柱形电池和 聚合物电池； 也适合与钴酸 锂或锰酸锂混 合使用 2 北大先行科技 产业有限公司 NCM-PU50A D50：10.5μm 振实密度：2.5g/cm3 比表面积：0.35m2/g 1.加工性能好，涂布压实3.5-3.6 2.放比容量较高，0.5C大于158 mAh/g 3.倍率性能好，常温循环800周 容量保持率大于90%，45℃800周 大于75%。 4.软包装电池85℃-4h高温存储 厚度变化小于2%。 CM-PU50B D50：10.8μm 振实密度：2.5g/cm3 比表面积：0.35m2/g 1.加工性能好，涂布压实3.5-3.6 2.放比容量较高，18650电池1C
放电比容量155mAh/g 3.倍率性能好，常温循环500周 容量保持率大于90%。 3 江特锂电材料 300吨/ 年 L532 D50：11.7μm 振实密度：2.35g/cm3 比表面积：0.43m2/g 比容量：155 mAh/g 应用于高容量 型数码电池产 品，可与钴酸 锂或锰酸锂混 合使用 L333 D50：10.7μm 振实密度：2.23g/cm3 比表面积：0.46m2/g 比容量：148 mAh/g L442 D50：11.44μm 振实密度：2.36g/cm3 比表面积：0.51m2/g 比容量：145 mAh/g 4. 江苏晶石科技 集团有限公司 SYF-9E（523材料） D50：10.05μm 振实密度：2.58g/cm3 首次效率：86.3% 0.2C放电：163 mAh/g 1C放电：150 mAh/g 5C放电：130 mAh/g YF-6B（333材料） D50：8.74μm 振实密度：2.56g/cm3 首次效率：89.5% 0.2C放电：158 mAh/g 1C放电：148 mAh/g 5C放电：135 mAh/g 5 济宁市无界科 技有限公司 WJ5100 D50：9-15μm 振实密度：≥2.5g/cm3 压实密度：≥3.6g/cm3 适用于高容量 和长寿命的铝 壳，聚合物， 圆柱形锂离子
Preparation of Polylactide/Graphene Composites From Liquid-Phase Exfoliated Graphite Sheets Xianye Li,1Yinghong Xiao,2Anne Bergeret,3Marc Longerey,3Jianfei Che1 1Key Laboratory of Soft Chemistry and Functional Materials,Nanjing University of Science and Technology, Nanjing210094,China 2Jiangsu Collaborative Innovation Center of Biomedical Functional Materials,Jiangsu Key Laboratory of Biomedical Materials,College of Chemistry and Materials Science,Nanjing Normal University, Nanjing210046,China 3Materials Center,Ales School of Mines,30319Ales Cedex,France Polylactide(PLA)/graphene nanocomposites were pre-pared by a facile and low-cost method of solution-blending of PLA with liquid-phase exfoliated graphene using chloroform as a mutual solvent.Transmission electron microscopy(TEM)was used to observe the structure and morphology of the exfoliated graphene. The dispersion of graphene in PLA matrix was exam-ined by scanning electron microscope,X-ray diffrac-tion,and TEM.FTIR spectrum and the relatively low I D/I G ratio in Raman spectroscopy indicate that the structure of graphene sheets(GSs)is intact and can act as good reinforcement fillers in PLA matrix.Ther-mogravimetric analysis and dynamic mechanical analy-sis reveal that the addition of GSs greatly improves the thermal stability of PLA/GSs nanocomposites.More-over,tensile strength of PLA/GSs nanocomposites is much higher than that of PLA homopolymer,increasing from36.64(pure PLA)up to51.14MPa(PLA/GSs-1.0). https://www.doczj.com/doc/be331118.html,POS.,35:396–403,2014.V C2013Society of Plastics Engineers INTRODUCTION Polylactide(PLA),a renewable,sustainable,biode-gradable,and eco-friendly thermoplastic polyester,has balanced properties of mechanical strength[1],thermal plasticity[2],and compostibility for short-term commod-ity applications[3,4].It is currently considered as a promising polymer for various end-use applications for disposable and degradable plastic products[5–8].Never-theless,improvement in thermal and mechanical proper-ties of PLA is still needed to pursue commercial success. To achieve high performance of PLA,many studies on PLA-based nanocomposites have been performed by incorporating nanoparticles,such as clays[9,10],carbon nanotubes[11–13],and hydroxyapatite[14].However, research on PLA-based nanocomposites containing gra-phene sheets(GSs)or graphite nanoplatelets has just started[15–17].GSs exhibit unique structural features and physical properties.It has been known that GSs have excellent mechanical strength(Young’s modulus of1,060 GPa)[18],electrical conductivity of104S/cm[19],high specific surface area of2,630m2/g[20],and thermal sta-bility[21].Polymer nanocomposites based on graphene show substantial property enhancement at much lower fil-ler loadings than polymer composites with conventional micron-scale fillers,such as glass[22]or carbon fibers [23],which ultimately results in lower filler ratio and simple processing.Moreover,the multifunctional property enhancement of nanocomposites may create new applica-tions of polymers. However,the incorporation of graphene into PLA matrix is restricted by cost and yield.Although the weak interactions that hold GSs together in graphite allow them to slide readily over each other,the numerous weak bonds make it difficult to separate GSs homogeneously in sol-vents and polymer matrices[24].Many methods have been reported for exfoliation of graphite,such as interca-lation with alkali metals[25]or oxidation in strong acidic conditions[26–29].Recently,exfoliation of graphite in liquid-phase was found to be able to give oxide-free GSs with high quality and yield at relatively low cost[30–35]. Correspondence to:Y.H.Xiao;e-mail:yhxiao@https://www.doczj.com/doc/be331118.html, or J.F.Che; e-mail:xiaoche@https://www.doczj.com/doc/be331118.html, Contract grant sponsor:Specialized Research Fund for the Doctoral Program of Higher Education of China;contract grant number: 20123219110010;contract grant sponsor:Natural Science Foundation of Jiangsu Province of China;contract grant number:BK2012845;contract grant sponsors:Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD),contract grant sponsor:Financial support for short visit from Ales School of Mines,France. DOI10.1002/pc.22673 Published online in Wiley Online Library(https://www.doczj.com/doc/be331118.html,). V C2013Society of Plastics Engineers POLYMER COMPOSITES—2014
常熟理工学院学报（自然科学）Journal of Changshu Institute Technology （Natural Sciences ）第26卷第10Vol.26No.102012年10月Oct.,2012 收稿日期：2012-09-05 作者简介：季红梅（1982—），女，江苏启东人，讲师，工学硕士，研究方向：无机功能材料．水热合成Fe 2O 3/石墨烯纳米 复合材料及其电化学性能研究 季红梅1，于湧涛2，王露1，王静1，杨刚1 （1.常熟理工学院化学与材料工程学院，江苏常熟215500；2.吉林石化公司研究院，吉林吉林132021） 摘要：利用水热法成功合成了Fe 2O 3/石墨烯（RGO ）锂离子电池负极材料.导电性能良好的石墨烯网络起到连接导电性能极差的Fe 2O 3和集流体的作用.电化学性能测试表明，180℃下得到的 Fe 2O 3/RGO 具有良好的比容量和循环稳定性.在不同倍率充放电过程中，初始放电比容量为1023.6mAh/g （电流密度为40mA/g ），电流密度增加到800mA/g 时，放电比容量维持在406.6 mAh/g ，大于石墨的理论放电比容量~372mAh/g.在其他较高的电流密度下比容量均保持基本不变.该Fe 2O 3/RGO 有望成为高容量、低成本、低毒性的新一代锂离子电池负极材料.关键词：Fe 2O 3；石墨烯；负极材料中图分类号：TM911文献标识码：A 文章编号：1008-2794（2012）10-0055-05 自从P.Poizot [1]等报道过渡金属氧化物可以作为锂离子电池负极材料这一研究后，金属氧化物负极便逐渐引起人们的重视.铁的氧化物具有比容量大、倍率性能好和安全性能高等优点，且原料来源丰富、价格低廉、环境友好，因此是一类很有发展潜力的动力锂离子电池负极材料.Fe 2O 3作为一种常温下最稳定的铁氧化合物，理论容量为1005mAh/g ，远高于石墨类材料的理论比容量，已经成为锂离子电池负极材料的一个研究热点.近年来，石墨烯由于其高的电传导性，大的比表面积，良好的化学稳定性和柔韧性而被尝试用于与活性锂离子电池负极材料复合，提升材料的电化学性能.比如，Cui Y [2]课题组在溶剂热条件下两步法得到Mn 3O 4与石墨烯的复合材料，改善了Mn 3O 4的比容量和循环性能.Co 3O 4，Fe 3O 4等金属氧化物材料与石墨烯复合也有被研究，本课题组在石墨烯和金属氧化物材料复合方面也做了大量的工作[3].本文通过水热法一步合成Fe 2O 3/石墨烯纳米复合材料，并研究了其电化学性能，合成过程中采用三乙烯二胺提供反应的碱性环境，并控制Fe 2O 3的粒子生长.1 实验 1.1试剂和仪器 三乙烯二胺（C 6H 12N 2）；无水三氯化铁（FeCl 3）；石墨；硝酸钠（NaNO 3）；浓硫酸（H 2SO 4）；高锰酸钾（KMnO 4）；双氧水（H 2O 2）和盐酸（HCl ），以上试剂均为分析纯.实验用水为去离子水.日本理学H-600型透射电子显微镜；日本理学D/max2200PC 型X 射线衍射仪；德国Bruker Vector 22红外光谱仪；日本JEOL-2000CX 透射电镜；美国Thermo Scientific Escalab 250Xi 光电子能谱仪；LAND 电池
纽扣电池型号对照表 扣式电池button battery 总高度小于直径的圆柱形电池，形似纽扣或硬币 纽扣电池的型号通常是在纽扣电池的背面由字母和阿拉伯数字组成。下面例举两种材料的纽扣电池的型号对照表。 纽扣电池新旧型号对照表 LR---水银--1.5V，SR---氧化银--1.55V，CR---锂电--3V，ZA---锌空--1.4V 氧化银纽扣电池是最常用的手表电池，绝大部分的手表使用的是氧化银纽扣电池。新电池的电压一般在1.55V到1.58V之间，电池的保质期是3年。在一块运行良好的手表上使用其运行时间一般不低于两年。 纽扣锂电池，3V锂纽扣电池多使用于防盗器，门禁，电脑等处，有的手表也配备锂电池。锂电池的保质期为7年，在一般情况下用户一般不用担心电池过期。 瑞士的氧化银纽扣电池型号为3##，日本的型号通常是SR###SW，或SR###W（#代表一个阿拉伯数字）。纽扣锂电池的型号通常为CR####。不同材料的纽扣电池，其型号规格也就不同。
大小尺寸mm 瑞士型号 = 日本型号 4.8 x 1.6 mm 337＝SR416SW 5.8 x 1.2 mm 335＝SR512SW 5.8 x 1.6 mm 317＝SR516SW 5.8 x 2.1 mm 379＝SR521SW 5.8 x 2.6 mm 319＝SR527SW 6.8 x 1.4 mm 339＝SR614SW 6.8 x 1.6 mm 321＝SR616SW 6.8 x 2.1 mm 364＝SR621SW 6.8 x 2.6 mm 377＝SR626SW 7.9 x 1.2 mm 346＝SR712SW 7.9 x 1.4 mm 341＝SR714SW 7.9 x 1.6 mm 315＝SR716SW 7.9 x 2.1 mm 362＝SR721SW 7.9 x 2.6 mm 397＝SR726SW 7.9 x 3.1 mm 329＝SR731SW 7.9 x 3.6 mm 384＝SR741SW 7.9 x 5.4 mm 309＝SR754SW 9.5 x 1.6 mm 373＝SR916SW 9.5 x 2.1 mm 371＝SR920SW 9.5 x 2.6 mm 395＝SR927SW 9.5 x 3.6 mm 394＝SR936SW 11.6 x 1.6 mm 366＝SR1116SW 11.6 x 2.1 mm 381＝SR1120SW 11.6 x 3.1 mm 390＝SR1130SW 11.6 x 3.6 mm 344＝SR1136SW 11.6 x 4.2 mm 301＝SR1143SW 11.6 x 5.4 mm 303＝SR1144SW 锂-二氧化锰纽扣电池型号对照表——CR系列
石墨烯复合材料的研究及其应用 任成，王小军，李永祥，王建龙，曹端林 摘要：石墨烯因其独特的结构和性能，成为物理化学和材料学界的研究热点。本文综述了石墨烯复合材料的结构和分类，主要包括石墨烯-纳米粒子复合材料、石墨烯-聚合物复合材料和石墨烯-碳基材料复合材料。并简述石墨烯复合材料在催化领域、电化学领域、生物医药领域和含能材料领域的应用。 关键词：石墨烯；复合材料；纳米粒子；含能材料 Research and Application of Graphene composites ABSTRACT: Graphene has recently attracted much interest in physics,chemistry and material field due to its unique structure and properties. This paper reviews the structure and classification of graphene composites, mainly inclouding graphene-nanoparticles composites, graphene-polymer composites and graphene-carbonmaterials composites. And resume the application of graphene composites in the field of catalysis, electrochemistry, biological medicine and energetic materials. Keywords: graphene; composites; nanoparticles; energetic materials 石墨烯自2004年曼彻斯特大学Geim[1-3]等成功制备出以来，因其独特的结构和性能，颇受物理化学和材料学界的重视。石墨烯是一种由碳原子紧密堆积构成的二维晶体，是包括富勒烯、碳纳米管、石墨在内的碳的同素异形体的基本组成单元。石墨烯的制备方法主要有机械剥离法，晶体外延法，化学气相沉积法，插层剥离法以及采用氧化石墨烯的高温脱氧和化学还原法等[4-10]。与碳纳米管类似，石墨烯很难作为单一原料生产某种产品，而主要是利用其突出特性与其它材料体系进行复合．从而获得具有优异性能的新型复合材料。而氧化石墨烯由于其特殊的性质和结构，使其成为制备石墨烯和石墨烯复合材料的理想前驱体。本文综述了石墨烯复合材料的结构、分类及其在催化领域、电化学领域、生物医药领域和含能材料领域的应用。
高分子／石墨烯纳米复合材料研究进展 高秋菊１，夏绍灵１，２＊ ，邹文俊１，彭 进１，曹少魁２ （１．河南工业大学材料科学与工程学院，郑州 ４５０００１；２．郑州大学材料科学与工程学院，郑州 ４５００５２ ）收稿：２０１２－０１－０９；修回：２０１２－０４－ ２４；基金项目：郑州科技攻关项目（０９１０ＳＧＹＧ２３２５８－ １）；作者简介：高秋菊（１９８４—），女，硕士研究生，主要从事高分子复合材料的研究。Ｅ－ｍａｉｌ：ｇａｏｑｉｕｊ ｕ２００８＠ｙａｈｏｏ．ｃｏｍ．ｃｎ；＊通讯联系人，Ｔｅｌ：０３７１－６７７５８７２２；Ｅ－ｍａｉｌ：ｓｈａｏｌｉｎｇ ＿ｘｉａ＠ｈａｕｔ．ｅｄｕ．ｃｎ． 摘要： 石墨烯以其优异的力学、光学、电学和热学性能，得到日益广泛的关注和研究。本文介绍了石墨烯的结构、性能和特点，并对石墨烯的改性方法进行了概括。本文着重综述了高分子／石墨烯纳米复合材料的研究现状和进展，并介绍了高分子／石墨烯纳米复合材料的三种制备方法，即原位插层聚合法、溶液插层法和熔融插层法。此外，还对高分子／石墨烯纳米复合材料的应用前景进行了展望，并对石墨烯复合材料研究存在的问题和未来的研究方向进行了讨论。 关键词：石墨烯；高分子；纳米复合材料；研究进展 引言 石墨烯是以ｓｐ２ 杂化连接的碳原子层构成的二维材料， 其厚度仅为一个碳原子层的厚度。这种“只有一层碳原子厚的碳薄片”，被公认为目前世界上已知的最薄、最坚硬、最有韧性的新型材料。石墨烯具 有超高的强度，碳原子间的强大作用力使其成为目前已知力学强度最高的材料。石墨烯比钻石还坚硬， 强度比世界上最好的钢铁还高１００倍［１］ 。石墨烯还具有特殊的电光热特性， 包括室温下高速的电子迁移率、 半整数量子霍尔效应、自旋轨道交互作用、高理论比表面积、高热导率和高模量、高强度，被认为在单分子探测器、集成电路、场效应晶体管等量子器件、功能性复合材料、储能材料、催化剂载体等方面有广泛 的应用前景［ ２］ 。石墨烯是一种疏松物质，在高分子基体中易团聚，而且石墨烯本身不亲油、不亲水，在一定程度上也限制了石墨烯与高分子化合物的复合，尤其是纳米复合。因而，很多学者对石墨烯的改性进行了大量的研究，以提高石墨烯和高分子基体的亲和性，从而得到优异的复合效应。 １ 石墨烯的改性方法 １．１ 化学改性石墨烯 该方法基于改性Ｈｕｍｍｅｒｓ法［３］ 。首先，由天然石墨制得石墨氧化物， 再通过几种化学方法获得可溶性石墨烯。其化学方法包括：氧化石墨在稳定介质中的还原［４］、通过羧基酰胺化的共价改性［５］ 、还原氧化石墨烯的非共价功能化［ ６］、环氧基的亲核取代［７］、重氮基盐的耦合［８］ 等。此外，还出现了对石墨烯的氨基化［９］、酯化［１０］、异氰酸酯［１１］ 改性等。用化学功能化的方法对石墨烯进行改性，不仅可以提高其溶解性 和加工性能，还可以增强有机高分子间的相互作用。１．２ 电化学改性石墨烯 利用离子液体对石墨烯进行电化学改性已见报道［１２］ 。用电化学的方法，使石墨变成用化学改性石 墨烯的胶体悬浮体。石墨棒作为阴极，浸于水和咪唑离子液的相分离混合物中。以１０～２０Ｖ的恒定电 · ７８· 第９期 高 分 子 通 报
附件1 2018年度有色金属行业统计工作先进单位 工作单位 中国铝业集团有限公司 中国铝业股份有限公司 中国稀有稀土有限公司 中铝国际工程股份有限公司 五矿有色金属控股有限公司 中国有色矿业集团有限公司 国家电力投资集团有限公司 河北省冶金行业协会 华北铝业有限公司 山西省冶金工业行业管理办公室 中条山有色金属集团有限公司 中铝山西铝业有限公司 中铝山西新材料有限公司 山西兆丰铝电有限责任公司 山西华兴铝业有限公司 国家电投集团山西铝业有限公司 国家电投集团内蒙古能源有限公司 内蒙古霍煤鸿骏铝电有限责任公司 中电投霍林河煤电集团铝业股份有限公司 包头铝业有限公司 赤峰中色锌业有限公司 内蒙古霍林河煤业集团有限责任公司 赤峰中色白音诺尔矿业有限公司 内蒙古锦联铝材有限公司
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石墨烯复合材料 石墨烯是单层碳原子通过sp2杂化形成的蜂窝点阵结构，属于二维原子晶体，此独特的空间结构，给石墨烯带来了优异的电学、力学、热学和比表面积大等性质。但是二维石墨烯由于片层之间具有较强的π-π作用和范德华力，使得石墨烯容易聚集形成石墨，限制了石墨烯在各个领域中的应用。因此，为了防止石墨烯的聚集和拓展石墨烯的应用，科研工作者将石墨烯与高分子或者无机纳米粒子进行复合，从而得到具有优异性能的复合材料。石墨烯的复合材料具有化学稳定性高、比表面积大，易回收等特点，在环境治理方面受到了科学家的青睐。 一、石墨烯复合材料的分类和制备 1、石墨烯-高分子复合材料 石墨烯-高分子复合材料，石墨烯的独特的结构和性能，对于改善高分子的导电性、热性能和吸附能力等方面有非常大的应用价值。制备石墨烯-高分复合材料最直接的方法是将高分子溶液与石墨烯的溶液混合，其中高分子和填充物在溶剂中的溶解能力是保证最佳分散度的重要因素。因此，在溶液混合时，可以将石墨基质表面功能化来提高它在多种溶剂中的溶解度。例如，异氰酸
苯酯修饰的GO在在聚苯乙烯的DMF溶液中表现出了较好的溶解度。 2、石墨烯-无机纳米粒子复合材料 无机纳米粒子存在着易于团簇的问题，并且选择合适的载体也是其广泛应用需要解决的问题。石墨烯具有多种优异的性能，并且具有较大的比表面积，可以成为无机纳米材料的载体。无机纳米粒子可以将易于团簇的石墨烯片层分开，防止团簇，从而两者形成石墨烯-无机纳米粒子新型的复合材料，这些材料广泛的应用于检测、催化和气体存储等方面。目前已报道的有负载的金属纳米粒子Ag、Au、氧化物纳米粒子ZnO和Fe3O4等。 3、其它石墨烯复合材料 石墨烯不仅仅可以和高分子、无机纳米材料复合，还可以同时结合高分子、纳米粒子和碳基材料中的一种或者两种，形成多元的含有石墨烯的复合材料。这类材料具有多功能性，用于超级电容器或者传感器等。 二、石墨烯复合材料在水治理的应用 1、吸附作用 碳材料中活性碳和碳纳米管被广泛的应用于水净化领域，将石墨烯与其它化合物进行复合，这些复合材料在吸附污染物上有非常高的效率，可以应用于染料、多芳香环烃和汽油的吸附。比如利用磁性-壳聚糖-石墨烯的复合材料可以大大提高去除溶液中的亚甲基蓝的效率，吸附能力达到
序号型号额定电压(V)额定容量 (Ah) 外型尺?（mm）长宽? 13-DZM-10610151±250±194±2 26-DZM-7A127151±265±196±2 36-DZM-7127116±286±1102±2 46-DZM-101210151±299±194±2 56-DZM-121212151±299±197±2 66-DZM-141214151±299±1116±2 76-DZM-161216151±299±1123±2 86-DZM-171217181±277±1167±2 96-DZM-201220181±277±1170±2 106-DZM-20(2*3)1220190±2113±1127±2 116-DZM-241224166±2175±1125±2 126-DZM-251225320±281±1119±2 136-DZM-261226312±280±1125±2 146-DZM-271227196±2130±1154±2 156-DZM-27（B）1227175±2166±1126±2 166-DZM-281228320±281±1127±2 176-DZM-301230267±277±1170±2 186-DZM-321232197±2165±2165±2 196-EVF-381238222±2106±1171±2 206-EVF-451245226±2120±1175±2 216-EVF-481248197±2165±2165±2 228-DZM-101610151±2101±1109±2 238-DZM-141614201±2112±1100±2 248-DZM-161616201±2112±1110±2 258-DZM-181618250±2100±2126±2 268-DZM-201620250±2100±2129±2 278-DZM-251625250±2130±2129±2 286-EVF-241224190±2115±1127±2
石墨烯基复合材料的制备及吸波性能研究 进展 摘要随着吉赫兹（GHz）频率范围的电磁波在无线通信领域的广泛应用，诸如电磁干扰、信息泄露等问题亟待解决。此外，军事领域中的电磁隐身技术与导弹的微波制导需要，使得电磁波吸收材料受到持续而广泛的关注。因此，迫切需要发展一种厚度薄、频带宽、强吸收的吸波材料。 石墨烯作为世界上最薄硬度最强的纳米材料，优点很多，例如石墨烯制成的片状材料中，厚度最薄，比表面积较大，具有超过金刚石的强度等，这些优点满足吸波材料的需求。石墨烯基复合材料在满足吸波材料基本要求的基础上又提升了材料吸收波的能力。 本文简单地介绍了吸波材料及石墨烯，综述概况了石墨烯基复合材料的研究现状，包括石墨烯复合材料制备方法、微观形貌以及复合材料的吸波性能，提出了石墨烯基复合吸波材料未来的发展方向。 关键词石墨烯基；吸波材料；纳米材料
Progress in Preparation and absorbing properties of graphene-based composites Abstract With the gigahertz (GHz) frequency range of the electromagnetic waves are widely used in wireless communications, such as electromagnetic interference, information leaks and other problems to be solved. In addition, military stealth technology in the field of electromagnetic and microwave guided missiles require such electromagnetic wave absorbing material is subjected to a sustained and widespread concern. Therefore, an urgent need to develop a thin, wide frequency band, a strong absorption of absorbing materials. Graphene as the strongest of the world's thinnest hardness nanomaterials, has many advantages, such as a sheet material made of graphene, the thinnest, large specific surface area, with more than a diamond of strength, these benefits meet absorbers It needs. Graphene-based composites on the basis of absorbing materials to meet the basic requirements but also enhance the ability of the material to absorb waves. This article briefly describes the absorbing material and graphene, graphene reviewed before the status quo based composite materials research, including graphene composite material preparation, morphology and absorbing properties of composites made of graphene-based composite
石墨烯在复合材料中的应用 龚欣 （东南大学机械工程学院南京211189） 摘要：介绍了石墨烯与有机高聚物、无机纳米粒子以及其它碳基材料的复合物，同时展望了这些材料在相关领域中的应用前景． 关键词：石墨烯纳米复合材料 2004年至今, 关于石墨烯的研究成果已在SCI检索期刊上发表了超过2000篇论文, 石墨烯开始超越碳纳米管成为了备受瞩目的国际前沿和热点．基于石墨烯的纳米复合材料在能量储存、液晶器件、电子器件、生物材料、传感材料和催化剂载体等领域展现出许多优良性能，具有广阔的应用前景．目前研究的石墨烯复合材料主要有石墨烯/聚合物复合材料和石墨烯/无机物复合材料两类，其制备方法主要有共混法、溶胶-凝胶法、插层法和原位聚合法.本文将对石墨烯的纳米复合材料及其性能等方面进行简要的综述． 一、基于石墨烯的复合物 利用石墨烯优良的特性与其它材料复合可赋予材料优异的性质．如利用石墨烯较强的机械性能，将其添加到高分子中，可以提高高分子材料的机械性能和导电性能；以石墨烯为载体负载纳米粒子，可以提高这些粒子在催化、传感器、超级电容器等领域中的应用． 1.1 石墨烯与高聚物的复合物 功能化后的石墨烯具有很好的溶液稳定性，适用于制备高性能聚合物复合材料．根据实验研究，如用异氰酸酯改性后的氧化石墨烯分散到聚苯乙烯中，还原处理后就可以得到石墨烯-聚苯乙烯高分子复合物．该复合物具有很好的导电性，添加体积分数为1%的石墨烯时，常温下该复合物的导电率可达0.1S/M，可在导电材料方面得到的应用． 添加石墨烯还可显著影响高聚物的其它性能，如玻璃化转变温度(Tg)、力学和电学性能等．例如在聚丙稀腈中添加质量分数约1%的功能化石墨烯，可使其Tg 提高40℃．在聚甲基丙烯酸甲酯（PMMA）中仅添加质量分数0.05%的石墨烯就可以将其Tg提高近30℃．添加石墨烯的PMMA比添加膨胀石墨和碳纳米管的PMMA具有更高的强度、模量以及导电率．在聚乙烯醇（PVA）和PMMA中添加质量分数0.6% 的功能化石墨烯后，其弹性模量和硬度有明显的增加．在聚苯胺中添加适量的氧化石墨烯所获得的聚苯胺-氧化石墨烯复合物的电容量（531F/g）比聚苯胺本身的电容量（约为216F/g）大1倍多，且具有较大的拉伸强度（12.6MPa）．这些性能为石墨烯-聚苯胺复合物在超级电容器方面的应用创造了条件． 石墨烯在高聚物中还可形成一定的有序结构．通过还原分散在Nafition膜中
河北工业大学 材料科学与工程学院 石墨烯及其纳米复合材料发展概况 专业金属材料 班级材料116 学号111899 姓名李浩槊 2015年01月05日
摘要 自从2004年，英国曼彻斯特大学物理学家安德烈·海姆和康斯坦丁·诺沃肖洛夫，成功地在实验中从石墨中分离出石墨烯，石墨烯因其优异的力学、电学和热学性能已经成为备受瞩目的研究热点。 石墨烯的碳原子排列与石墨的单原子层雷同，是碳原子以sp2混成轨域呈蜂巢晶格(honeycomb crystal lattice)排列构成的单层二维晶体。石墨烯可想像为由碳原子和其共价键所形成的原子尺寸网。石墨烯是世上最薄也是最坚硬的纳米材料，它几乎是完全透明的，只吸收2.3%的光；导热系数高达5300 W/（m·K），高于碳纳米管和金刚石，常温下其电子迁移率超过15000 cm2 /（V·s），又比纳米碳管或硅晶体高，而电阻率只约10-6Ω·cm，比铜或银更低，为世上电阻率最小的材料。因为它的电阻率极低，电子跑的速度极快，因此被期待可用来发展出更薄、导电速度更快的新一代电子元件或晶体管。由于石墨烯实质上是一种透明、良好的导体，也适合用来制造透明触控屏幕、光板，甚至是太阳能电池。 石墨烯的结构非常稳定，石墨烯内部的碳原子之间的连接很柔韧，当施加外力于石墨烯时，碳原子面会弯曲变形，使得碳原子不必重新排列来适应外力，从而保持结构稳定。这种稳定的晶格结构使石墨烯具有优秀的导热性。 但是，因为石墨烯片层之间存在很强的范德华力，导致其很容易堆积团聚，在一般溶剂中的分散性很差，所以其应用领域受到了限制。本文通过收集、查阅多篇有关石墨烯研究的论文，分析、整理了石墨烯及其纳米复合材料的制备技术发展及其应用的相关知识、理论。 关键词：石墨烯纳米材料制备复合材料
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序号公司名称产能产量性能应用领域使用 公司 1 湖南长远锂科 有限公司 500吨/ 年LY303 克容量大于143mAh/g,压实密度 高 圆柱形电池， 铝壳电池和聚 合物电池 LY304 克容量大于145mAh/g,体积比容 量高 高容量型电池 LY305 克容量大于155mAh/g,循环性能 好 圆柱形电池和 聚合物电池； 也适合与钴酸 锂或锰酸锂混 合使用 2 北大先行科技 产业有限公司NCM-PU50A D50：10.5μm 振实密度：2.5g/cm3 比表面积：0.35m2/g 1.加工性能好，涂布压实3.5-3.6 2.放比容量较高，0.5C大于158 mAh/g 3.倍率性能好，常温循环800周容量保持率大于90%，45℃800周大于75%。 4.软包装电池85℃-4h高温存储厚度变化小于2%。 CM-PU50B D50：10.8μm 振实密度：2.5g/cm3 比表面积：0.35m2/g 1.加工性能好，涂布压实3.5-3.6
2.放比容量较高，18650电池1C 放电比容量155mAh/g 3.倍率性能好，常温循环500周容量保持率大于90%。 3 江特锂电材料 300吨/ 年L532 D50：11.7μm 振实密度：2.35g/cm3 比表面积：0.43m2/g 比容量：155 mAh/g 应用于高容量 型数码电池产 品，可与钴酸 锂或锰酸锂混 合使用 L333 D50：10.7μm 振实密度：2.23g/cm3 比表面积：0.46m2/g 比容量：148 mAh/g L442 D50：11.44μm 振实密度：2.36g/cm3 比表面积：0.51m2/g 比容量：145 mAh/g 4. 江苏晶石科技 集团有限公司SYF-9E（523材料） D50：10.05μm 振实密度：2.58g/cm3 首次效率：86.3% 0.2C放电：163 mAh/g 1C放电：150 mAh/g 5C放电：130 mAh/g YF-6B（333材料） D50：8.74μm 振实密度：2.56g/cm3 首次效率：89.5% 0.2C放电：158 mAh/g 1C放电：148 mAh/g 5C放电：135 mAh/g 5 济宁市无界科 技有限公司WJ5100 D50：9-15μm 适用于高容量 和长寿命的铝