Supplementary Materials for

Size: px

Start display at page:

Download "Supplementary Materials for"

Randolph Horn
6 years ago
Views:

1 advanes.sienemag.org/gi/ontent/full/3/4/e /dc1 Supplementary Materials for Single-layer nanosheets with exeptionally high and anisotropi hydroxyl ion ondutivity Pengzhan Sun, Renzhi Ma, Xueyin Bai, Kunlin Wang, Hongwei Zhu, Takayoshi Sasaki This PDF file inludes: Pulished 14 April 2017, Si. Adv. 3, e (2017) DOI: /siadv Supplementary Materials and Methods fig. S1. SEM haraterizations of as-synthesized and anion-exhanged s. fig. S2. XRD haraterizations of as-synthesized and anion-exhanged s. fig. S3. AFM haraterizations of nanosheets with different sizes. fig. S4. Shemati drawings for nanosheets on om eletrodes. fig. S5. Impedane spetra of are om eletrodes aquired at 30 C and 80% RH. fig. S6. SEM haraterizations of nanosheet multilayers. fig. S7. Hydroxyl ion ondution of nanosheet multilayers. fig. S8. Hydroxyl ion ondution of multilayer assemlies omposed of miroand nano-sized nanosheets. fig. S9. Temperature dependenes of in-plane ioni ondutivity for a representative sample of miro Mg-Al nanosheet multilayers deposited on om eletrodes during a large time interval of over half a year to show the longterm staility of exfoliated nanosheets in terms of hydroxyl ion ondution. fig. S10. SEM haraterizations of nanosheet memranes. fig. S11. Cross-plane hydroxyl ion ondution of nanosheets aquired with lamellar memranes. fig. S12. Isotope effet experiments. fig. S13. XRD patterns of Mg-Al and Co-Al nanosheet multilayers. fig. S14. Representative Nyquist plots of impedane for pellets ontaining Co-Al- CO3 2 platelets. fig. S15. Hydroxyl ion ondution of platelet-ased pellets.

2 Supplementary Materials Supplementary Materials and Methods SEM, XRD and AFM haraterizations Sanning eletron mirosopy (SEM) and X-ray diffration (XRD) haraterizations of as-synthesized s were shown in figs. S1 and S2. All the platelets were well-rystallized with a regular hexagonal shape, whih were not hanged upon anion exhange (fig. S1). The exhanged platelets were transformed into other anioni forms with a different interlayer spaing as identified in XRD patterns (fig. S2). For the different anion-interalated platelets, the interlayer distanes generally followed the order: NO3 > Cl /Br - > CO3 2 (fig. S2). The haraterizations of Mg3/4-Al1/4-CO3 2 s, whih were synthesized y the typial o-preipitation method with small size and irregular shape, were also inluded for omparison. In partiular, as shown in fig. S2 and d, after topohemial oxidative interalation, ruite-like β-co(oh)2 and Co2/3Ni1/3(OH)2 hexagonal platelets (interlayer spaing: ~0.46 nm) were transformed into hydrotalite-like Co 2+ 2/3-Co 3+ 1/3-Br - and Co2/3-Ni1/3-Br - s with an interlayer spaing of ~0.77 nm. Further exhange into CO3 2 forms ould yield an interlayer spaing of ~0.75 nm, in agreement with that of Mg2/3-Al1/3-CO3 2 and Co2/3-Al1/3-CO3 2 s. Treating NO3 - -exhanged platelets in formamide with either soniation for 3 h or mehanial shaking for 2 days ould yield single-layer nanosheets with lateral dimensions on the order of several hundred nanometers or several mirometers, respetively. Atomi fore mirosopy (AFM) images of as-prepared Mg-Al and Co-Al nanosheets were shown in Fig.3a as well as fig. S3, displaying an estimated thikness of ~0.8 nm. Calulation of ioni ondutivities For nanosheet-ased lamellar memranes (ross-plane ondutane) and platelet-ased pellets (ulk and average ondutane), the ioni ondutivity (σ) ould e alulated as σ = d/(r S), where R is the measured ulk resistane, d is the thikness of the sample, whih ould e

3 determined from SEM oservations, S is the effetive surfae area of eletrodes ontating with the sample (6 mm in diameter). Shemati diagrams with aurate dimensions of om eletrodes are shown in fig. S4. 65 pairs of opposite om teeth (width length: 2 μm 2 mm) were onneted in parallel. Eah two om teeth were separated with a gap of 2 μm. The resistane of are om eletrode was extremely high (>100 MΩ, as shown in fig. S5), indiating no sustantial ontriution to the susequent impendene measurements. For nanosheets assemled on om eletrodes (31 33), the ioni ondutivity ould e alulated as σ = W/(R T L): W is the width of the nanosheet film, whih was fixed as 2 μm for all the samples; T is the thikness of the film, whih ould e determined from AFM measurements; L is the total length of nanosheets onneting two opposite eletrode teeth, whih ould e otained y oserving the nanosheet geometri morphologies in SEM. For single-layer deposition (fig. S4a), two types of nanosheets were mainly present on om eletrodes: ridging nanosheets and interior nanosheets. Bridging nanosheets onneted two opposite teeth and dominated ioni ondutivity, whereas interior nanosheets loated on a single tooth or in the gap etween two opposite teeth without effetive onnetion, thus playing negligile roles. For the alulation of L, interior nanosheets were exluded and the overall L value was the sum of lengths (l) of all the ridging nanosheets. A statistial method was employed for the alulation of L y SEM oservation proposed efore (31, 32). 50 random spots were hosen throughout the om eletrode area. In eah spot, the estimated L value (Lx) was alulated as Lx = (l1 + l2 + l3 + ) Stotal/Sx, where Stotal is the effetive area of om eletrode ( m 2 ) and Sx is the spot area in SEM oservation. Based on all the Lx values, L ould e statistially alulated as L = ΣLx/50. For multilayer deposition (fig. S4), the total area (Sfilm) of nanosheet multilayer film on om

4 eletrodes was alulated from its orresponding SEM oservations. Sfilm ontains two omponents: the areas on om teeth (Sfilm1) and etween opposite teeth (Sfilm2), respetively. As Sfilm1 made no ontriution to ioni ondutivity, whih ould e exluded, only Sfilm2 was onsidered for alulating L. Sine the width of a single om tooth and the gap etween two opposite teeth were equivalent (2 μm), L ould e alulated as L = Sfilm/ 2W. Water vapor onentration ell measurements By onstruting a water vapor onentration ell (36), the onduting ioni speies of nanosheets in humidified ondition were determined y measuring and omparing the eletromotive fores aross ation exhange memrane (Nafion 117, DuPont), anion exhange memrane (AHA, ASTOM Co.), graphene oxide (GO) memrane (prepared y drop-asing an aqueous suspension of GO nanosheets) and Mg-Al (Co-Al) nanosheet lamellar memranes, whih separated a flow of humidified and dry O2 stream, respetively. For ation exhange memrane (proton ondutor), the reations at wet and dry sides an e desried as follows Wet side: 2H2O O2 + 4H + + 4e Dry side: 4H + + O2 + 4e 2H2O For anion exhange memrane (hydroxyl ion ondutor), the reations are as follows Wet side: 2H2O + O2 + 4e 4OH Dry side: 4OH 2H2O + O2 + 4e Calulation of ativation energy (E) The ativation energy (E) for hydroxyl ion ondution was determined using the following

5 equation σt = Aexp( E k B T ) where σ is the ion ondutivity, T is the temperature, A is the Arrhenius fator and kb is the Boltzmann onstant. The linear fit of ln (σt) versus T 1 yielded E from the orresponding slope.

88 Intensity 003 006 -CO 2-3 -Cl - -Br -

74 0.75 Intensity 0 10 20 30 40 50 60 70

6 Supplementary Figures a Mg 2/3 -CO 3 2- Mg-Al platelets Mg 2/3 -NO 3- Mg 3/4 -Al 1/4 -CO μm 10 μm Co-Al platelets -CO 2-3 -Cl - -NO 3- Co 2+ -Co 3+ platelets Bruite-like Co(OH) 2 Co 2+ 2/3-Co 3+ 1/3-Br - Co 2+ 2/3-Co /3-CO 3 d Bruite-like Ni 1/3 (OH) 2 Co-Ni platelets -Ni 1/3 -Br - -Ni 1/3 -CO 3 2- fig. S1. SEM haraterizations of as-synthesized and anion-exhanged s. a Intensity Mg 2/3 -CO 2-3 Mg 2/3 -NO - 3 Mg 3/4 -Al 1/4 -CO 2-3 d(003) / nm Intensity CO 2-3 -Cl - -Br - -NO - 3 d(003) / nm Intensity (Cu K ) Bruite-like Co(OH) 2 Co 2+ 2/3 -Co3+ 1/3 -Br- Co 2+ 2/3 -Co3+ 1/3 -CO 32- d(003) / nm d Intensity (Cu K ) Bruite-like Ni 1/3 (OH) 2 -Ni 1/3 -Br - -Ni 1/3 -CO 3 2- d(003) / nm (Cu K ) (Cu K ) fig. S2. XRD haraterizations of as-synthesized and anion-exhanged s.

a Miro-Co-Al sheets 5.0 Nano-Mg-Al sheets 7.0 Nano-Co-Al sheets 7.0 nm nm nm 1 μm 0.0 1 μm 0.0 1 μm 0.0 fig. S3.

AFM images of (a) miro-co-al nanosheets, () nano-mg-al nanosheets and () nano-co-al nanosheets, respetively.

a Total numer of om teeth: 65 pairs Total numer of om teeth: 65 pairs 2 μm 2 μm 2 mm Bridging nanosheets l 1 Interior nanosheets 2 mm 2 μm l 2 l 3 2 μm

7 a Miro-Co-Al sheets 5.0 Nano-Mg-Al sheets 7.0 Nano-Co-Al sheets 7.0 nm nm nm 1 μm μm μm 0.0 fig. S3. AFM haraterizations of nanosheets with different sizes. AFM images of (a) miro-co-al nanosheets, () nano-mg-al nanosheets and () nano-co-al nanosheets, respetively. Miro- and nano- denote several mirometer- and several hundred nanometer-sized nanosheets, respetively. a Total numer of om teeth: 65 pairs Total numer of om teeth: 65 pairs 2 μm 2 μm 2 mm Bridging nanosheets l 1 Interior nanosheets 2 mm 2 μm l 2 l 3 2 μm Equivalent model Equivalent length: ~130 mm Equivalent length: ~130 mm Equivalent model l 1 l 2 l 3 2 μm 2 μm fig. S4. Shemati drawings for nanosheets on om eletrodes. Shemati diagrams for (a) single-layer nanosheet and () multilayer nanosheet assemlies on om eletrodes with dimensions indiated. The red lines in (a) illustrate the deposition of om teeth in a folding line manner. The ottom panels show the orresponding equivalent models.

2.0 Bare om eletrodes 1.5 Z'' ( 10 8 Ω) 1.0 0.5 0.0 0.0 0.5 1.0 1.5 2.0 Z' ( 10 8 Ω) fig. S5. Impedane spetra of are om eletrodes aquired at 30 C and 80% RH.

SEM haraterizations of nanosheet multilayers. SEM images of (a) miro-mg-al, () miro-co-al and () nano-co-al nanosheet multilayer assemlies on om eletrodes. a Z'' (kω) 50 40 30 20 10 1.0 0.

0 RH 80% 30 o C 40 o C 50 o C 60 o C Miro-Mg-Al nanosheet multilayer 0 0 10 20 30 40 50 Z' (kω) 10-1 10-4 Miro-Mg-Al sheet multilayers RH: 50% ~20 nm thik 10-1 ~20 nm thik ~30 nm thik

8 2.0 Bare om eletrodes 1.5 Z'' ( 10 8 Ω) Z' ( 10 8 Ω) fig. S5. Impedane spetra of are om eletrodes aquired at 30 C and 80% RH. a Miro-Mg-Al sheet multilayers Miro-Co-Al sheet multilayers Nano-Co-Al sheet multilayers ~20 nm thik ~30 nm thik ~140 nm thik 10 μm 10 μm 10 μm fig. S6. SEM haraterizations of nanosheet multilayers. SEM images of (a) miro-mg-al, () miro-co-al and () nano-co-al nanosheet multilayer assemlies on om eletrodes. a Z'' (kω) RH 80% 30 o C 40 o C 50 o C 60 o C Miro-Mg-Al nanosheet multilayer Z' (kω) Miro-Mg-Al sheet multilayers RH: 50% ~20 nm thik 10-1 ~20 nm thik ~30 nm thik Miro-Mg-Al sheet multilayers Miro-Co-Al sheet multilayers fig. S7. Hydroxyl ion ondution of nanosheet multilayers. (a) Representative Nyquist plots of impedane for miro-mg-al nanosheet multilayer. The inset shows an enlarged view of the high-frequeny setion. Temperature-dependenes of in-plane ioni ondutivity for () miro-mg-al nanosheet multilayers at various RH and () miro-mg-al and Co-Al nanosheet multilayers at 80% RH.

9 a ~60 nm thik ~20 nm thik ~140 nm thik ~30 nm thik Miro-Mg-Al sheet multilayers Nano-Mg-Al sheet multilayers Miro-Co-Al sheet multilayers Nano-Co-Al sheet multilayers fig. S8. Hydroxyl ion ondution of multilayer assemlies omposed of miro- and nano-sized nanosheets. Temperature-dependenes of in-plane ioni ondutivity for (a) miro- and nano-mg-al nanosheet multilayers and () miro- and nano-co-al nanosheet multilayers Miro-Mg-Al sheet multilayers Pristine After half a year fig. S9. Temperature dependenes of in-plane ioni ondutivity for a representative sample of miro Mg-Al nanosheet multilayers deposited on om eletrodes during a large time interval of over half a year to show the long-term staility of exfoliated nanosheets in terms of hydroxyl ion ondution.

10 a Miro-Mg-Al sheet memrane Miro-Co-Al sheet memrane 1 m 10 μm 1 m 10 μm Nano-Mg-Al sheet memrane d Nano-Co-Al sheet memrane 10 μm 10 μm fig. S10. SEM haraterizations of nanosheet memranes. SEM images of the morphologies and ross-setions of (a, ) miro- and nano-mg-al nanosheet memranes and (, d) miro- and nano-co-al nanosheet memranes, respetively. The insets in a and are photographs of freestanding Mg-Al and Co-Al nanosheet memranes, respetively.

11 a Z'' (Ω) Miro-Mg-Al sheet memrane Z' (Ω) fig. S11. Cross-plane hydroxyl ion ondution of nanosheets aquired with lamellar memranes. (a) Representative Nyquist plots of impedane for miro-mg-al nanosheet memrane. The inset shows an enlarged view of the high-frequeny setion. (, ) Temperature-dependenes of ross-plane ioni ondutivity for miro- and nano-mg-al (Co-Al) nanosheets at various RH. (d) Linear fits of the plots of ln (σt) versus T 1 in for miro-co-al nanosheet memranes o C 40 o C 50 o C 60 o C RH: 50% Miro-sized sheets Nano-sized sheets Miro-sized sheets Nano-sized sheets Co-Al sheet memranes d ln ( T S m -1 K) Mg-Al sheet memranes Miro-sized sheets Nano-sized sheets RH: 50% Miro-sized sheets Nano-sized sheets Miro-Co-Al sheet memranes RH: 50% E = 0.22 ev E = 0.28 ev T -1 / K -1 The ross-plane hydroxyl ion ondutivities inreased with temperature and RH, ut the values for oth Mg-Al and Co-Al nanosheets were ultralow, whih were on the order of 10 6 S m 1 at 80% RH and even muh lower at 50% RH. Notaly, as the lateral dimension of nanosheets dereased from mirometer-size to several hundred nanometer-size, the ross-plane ondutivities inreased proportionally. Reduing the nanosheet lateral size gave rise to the inrease of the amount of interedge ondution hannels within the lamellar memranes, whih would provide more options for the propagating hydroxyl ions to hange their pathways and further aelerate ion ondution. These results indiate that the interedge hannels formed etween nanosheets

12 may ontriute to the ross-plane hydroxyl ion ondution. fig. S11d shows the linear fits of ln (σt) versus T 1 for miro-co-al nanosheets at 80% and 50% RH, respetively, the slops of whih yielded ativation energy E values for ross-plane hydroxyl ion ondutions. Inreasing RH from 50% to 80% led to a slight derease in E value, onfirming the positive role of water in ion ondution, whih was onsistent with the in-plane ase (Fig. 3e). a Z'' (kω) Single-layer Mg-Al nanosheets H 2 O Single-layer Mg-Al nanosheets D 2 O Amient (RH 80% 26 o C) D 2 O (RH 80% 26 o C)/15 min D 2 O (RH 80% 26 o C)/30 min D 2 O (RH 80% 26 o C)/60 min Z' (kω) Z'' (kω) d Miro-Mg-Al sheet multilayers H 2 O D 2 O Amient (RH 48% 26 o C) D 2 O (RH 48% 26 o C)/15 min D 2 O (RH 48% 26 o C)/30 min D 2 O (RH 48% 26 o C)/60 min Miro-Mg-Al sheet multilayers Z' (kω) fig. S12. Isotope effet experiments. Real-time measurements of the Nyquist plots of impedane for representative (a) single-layer and () multilayer Mg-Al nanosheet samples upon replaing the atmosphere from H2O to D2O under the same RH and temperature. The inset in eah figure shows an enlarged view of the high-frequeny setion. Temperature-dependenes of in-plane ioni ondutivity for representative () single-layer and (d) multilayer Mg-Al nanosheet samples in H2O and D2O, respetively, at 80% RH.

13 The isotope effet experiments were performed y measuring the Nyquist plots of impedane for nanosheet samples in H2O and D2O atmospheres, respetively, and alulating their orresponding ioni ondutivities. Representative samples of disrete single-layer and ontinuous multilayer Mg-Al nanosheets deposited on om eletrodes were hosen for the measurements. Firstly, the seleted nanosheet samples stored in amient onditions were transferred into the D2O-filled onstant temperature and humidity hamer, in whih the RH and temperature were onsistent with those in amient (e.g. RH 80%, T 26 o C for single-layer nanosheets and RH 48%, T 26 o C for multilayer nanosheets). The real-time variations of Nyquist plots of impedane were tested, as displayed in figs. S12a and. It is evident that the real-time Nyquist plots of impedane remained nearly unhanged with the replaement of the atmosphere from amient to D2O for oth the single- and multi-layer nanosheet samples. Next, at a fixed RH of 80%, the ioni ondutivities of representative nanosheet samples were measured as a funtion of temperature in H2O and D2O atmospheres, respetively, as shown in fig. S12 and d. Again, the temperature-dependenes of ioni ondutivity seemed to e independent of the atmosphere (i.e., H2O or D2O). From the negligile variations in ioni ondutivities of representative nanosheet samples when hanging the testing atmosphere from H2O to D2O, we ould infer that hydroxyl ions rather than protons originating from the self-dissoiation of water were the real vehile of ion ondution in nanosheets, eause of the tiny molar mass differene etween OH - (17.01) and OD (18.01) ompared to that etween H + (1.01) and D + (2.01).

14 001 Mg-Al nanosheet multilayer Co-Al nanosheet multilayer Intensity d(001) / nm (Cu K ) fig. S13. XRD patterns of Mg-Al and Co-Al nanosheet multilayers. The 001, 002 and 003 peaks were assigned to restaked nanosheets interalated with harge-alaning NO3 anions, water and formamide moleules, resulting in an interlayer spaing of ~1.1 nm. The shoulder around 10 o, orresponding to an interlayer spaing of ~0.8 nm, might e derived from a small portion of unexfoliated platelets or restaked nanosheets interalated with CO3 2- anions y atmospheri ontamination of CO2. Due to a preferential lamellar restaking of nanosheets, the in-plane refletions from host layers were not oserved.

15 Z'' (kω) o C 40 o C 50 o C 60 o C 70 o C 80 o C -CO Z' (kω) fig. S14. Representative Nyquist plots of impedane for pellets ontaining Co-Al-CO3 2 platelets. a 10-4 RH: 60% RH: 70% RH: 90% Mg 2/3 -CO 3 2- Mg 3/4 -Al 1/4 -CO CO CO Co-Al E = 0.32 ev E = 0.44 ev E = 0.27 ev CO 3 2- Cl - NO 3 - d Mg-Al-CO 3 2- Mg-Al-NO 3 - Co 2+ -Co 3+ -CO 3 2- Co 2+ -Co 3+ -Br - Co-Ni-CO 3 2- Co-Ni-Br Co 2+ 2/3 -Co3+ 1/3 -CO 32- -Ni 1/3 -CO 3 2- fig. S15. Hydroxyl ion ondution of platelet-ased pellets. Temperature-dependenes of ion ondutivity for pellets ontaining (a) Co-Al-CO3 2 platelets at various RH, () CO3 2 platelets with various host layer ompositions at 80% RH, () Co-Al platelets

16 interalated with various harge-alaning anions at 80% RH and (d) platelets with various host layer ompositions (Mg-Al, Co 2+ -Co 3+ and Co-Ni) and interlayer interalated anions (CO3 2, Br and NO3 ) at 80% RH. Taking Co-Al-CO3 2 s as an example, the ion ondutivities inreased with temperature and RH (figs. S14 and S15a). For CO3 2 s with various host layer ompositions (fig. S15), the ondutivities of Co-Al-CO3 2 s were at the highest, on the order of 10 5 ~10 4 S m 1 (30~80 o C, 80% RH), whereas the values of other samples (Mg-Al, Co 2+ -Co 3+ and Co-Ni) were on the order of 10 6 S m 1. Taking Co-Al s as an example, after anion exhange into monovalented forms, there existed a signifiant enhanement in ion ondutivities (fig. S15): ompared to CO3 2 s, the ondutivities of Cl s inreased y ~1 order of magnitude (10 4 S m 1 ) and the values of NO3 s inreased y 2 orders of magnitude (10 3 S m 1 ). Simultaneously, the ativation energy E values for Co-Al s dereased in the same order (fig. S15). The hange tendenies of ion ondutivity and related E value with respet to interlayer anion exhange omplied well with the XRD patterns (fig. S2), indiating that the inrease in the interlayer spaing of s might favor hydroxyl ion ondution. Similar results were otained with s earing various host layer ompositions (fig. S15d): the ondutivities of CO3 2 s (Mg-Al, Co 2+ -Co 3+ and Co-Ni), Br - s (Co 2+ -Co 3+ and Co-Ni) and NO3 s (Mg-Al) were on the order of 10 6, 10 4 and 10 3 S m -1, respetively.

UNDERSTANDING WHISKER PHENOMENON - PART II Competitive Mechanisms

UNDERSTANDING WHISKER PHENOMENON - PART II Competitive Mehanisms Chen Xu, Chonglun Fan, Anna Vysotskaya, Joseph A. Ays and Yun Zhang Luent Tehnologies, Eletroplating Chemials and Servies 236 Rihmond Valley