Controllable Growth of Monodisperse Multilayered Three-Dimensional

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Controllable Growth of Monodisperse Multilayered 3D Simonkolleite and Its Supercapacitor Activity Bo Song, Xia Cui, Yun Xie, Shisu Cheng, Yijiang Shao, and Yueming Sun Cryst. Growth Des., Just Accepted Manuscript • Publication Date (Web): 12 May 2017 Downloaded from http://pubs.acs.org on May 13, 2017

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Crystal Growth & Design

Controllable Growth of Monodisperse Multilayered 3D Simonkolleite and Its Supercapacitor Activity Bo Song,† Xia Cui,† Yun Xie,† Shisu Cheng,† Yijiang Shao,*,† and Yueming Sun*,‡ †

. Hefei Technology college, Hefei 238000, China

‡

. Jiangsu Province Hi-Tech Key Laboratory for Bio-Medical Research, School of Chemistry and

Chemical Engineering, Southeast University, Nanjing 211189, China

*Corresponding author. Tel: +86 551 82353505; Fax: +86 551 82353051 *Email: [email protected] (Y Shao), [email protected] (Y Sun)

1 ACS Paragon Plus Environment


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ABSTRACT

A unique multilayered three-dimensional (3D) simonkolleite with good monodispersity was successfully synthesized by a simple hydrothermal method. Against the preference for being two-dimensional (2D) nanoplate morphologies, the 3D structure growth was attributed to a novel molecule structure upon ionization of a soluble long-chain quaternary ammonium carboxylic acid. Ion-adjusted experiments were designed and carried out to make deep insight into the morphology revolution versus ionic environment, indicating that the ionized acid not only provided an essential prerequisite for forming simonkolleite but also acted as morphological directing agent to assist the formation of final 3D morphology. We further demonstrated the utility of the multilayered 3D simonkolleite as electrode material for supercapacitor which provided improved electrochemical performance in compare with 2D simonkolleite.


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INTRODUCTION A family of compounds known as “layered single-metal hydroxides” (LSHs) consist of positively charged single metal hydroxide layers with anions and water molecules intercalated in them.1 LSHs of general formula M2(OH)4-nx(An−)x·zH2O, where M(II) is Zn, Cu, Ni, Mn, or Co and X− is Cl−, NO3−, CH3COO− etc., are also called layered basic metal salts.2-6 So far, lots of researches have been reported to demonstrate the usage of these compounds as catalytic, magnetic, photochemical, and electrochemical materials due to their unique lamellar structure.7-10 Zinc chloride hydroxide monohydrate (Zn5(OH)8Cl2·H2O)11-13, as a typical LSH, is also named simonkolleite which is an occurring mineral form in nature.14, 15 Besides traditional application as a feed additive and nutrition supplement for animals,16, 17 simonkolleite has been recently reported new application in energy resources, such as electrode material for solar cells and supercapacitors with its morphological properties, unique physical and chemical properties.18, 19 For supercapacitor electrode, three-dimensional (3D) hierarchical micro/nanostructures have an advanced ability for electron transfer, structure stability and high surface area resulting in excellent charge-storage performances.20-23 Disappointingly, previous reports only focused on preparation of two-dimensional (2D) simonkolleite nanosheets or depositing monolayered nanosheets on substrates for forming simonkolleite-graphene accumulation to achieve electrode for supercapacitor.24,

25

Despite being synthesized under various conditions via a lot of synthetic

strategies, the synthesized simonkolleite usually presents as 2D nanosheet structure owing to its natural favorite.4,

26, 27

Thereby, great attention should be attracted to explore more suitable

approaches to the syntheses of simonkolleite with 3D structures as candidates for electrode materials.



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In this paper, we successfully synthesized monodisperse multilayered 3D simonkolleite by introducing a novel salt zinc N-dodecyl-N,N-dimethylammonioacetic chloride (Zn(DDAC)2). The anion DDAC−, of which the corresponding acid is N-dodecyl-N,N-dimethylammonioacetic acid chloride (DDAAC) as shown in Figure 1, is an amphiphilic ion mainly consisting of four parts such as chloride ion, acetate, long alkyl chain and quaternary ammonium groups. And ion-adjusted experiments were carried out to analyze the contribution of each group to the formation of multilayered simonkolleite. Furthermore, the multilayered simonkolleite acting as supercapacitor electrode material displays improved electrochemical performance in specific capacitance, rate performance and cycle stability.

Figure 1. The molecular structure of DDAAC with displacement ellipsoids drawn at the 30% probability level. EXPERIMENTAL SECTION Preparation of quaternary ammonium carboxylate zinc salt aqueous solution: 25.1 mmol DDAAC (see Supporting Information) was totally dissolved in 100 mL deionized water under stirring at 60 oC (solution pH = 0.63). Then 12.5 mmol ZnO powder was added into above solution with continuous stir at 60 oC to form homogeneous 125 mM Zn(DDAC)2 aqueous solution (pH ≈ 6). After cooling down to room temperature, the Zn(DDAC)2 aqueous solution was then diluted 50 mM with deionized water. Another three zinc salt aqueous solution with similar structure feature


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except for alkyl chain, zinc N-ethyl-N,N-dimethylammonioacetic chloride (Zn(EDAC)2), zinc N-butyl-N,N-dimethylammonioacetic

chloride

(Zn(BDAC)2)

and

zinc

N-octyl-N,N-dimethylammonioacetic chloride (Zn(ODAC)2) were also prepared by their corresponding acids N-ethyl-N,N-dimethylammonioacetic acid chloride (EDAAC, see Supporting Information), N-butyl-N,N-dimethylammonioacetic acid chloride (BDAAC, see Supporting Information) and N-octyl-N,N-dimethylammonioacetic acid chloride (ODAAC, see Supporting Information) via a same procedure above. Synthesis of multilayered simonkolleite in Zn(DDAC)2 aqueous solution: The solution was prepared by dissolving proper amount of hexamethylenetetramine (HMTA) in Zn(DDAC)2 aqueous solution under stirring. The molar ratio of HMTA and Zn2+ was 1:1 in the Zn(DDAC)2-HMTA system throughout this work. Then the solution was transferred to Teflon-lined steel autoclaves where clear FTO glass substrates were placed to collect the product and maintained at 105 oC for 4 h. The precipitate was washed by deionized water and ethanol and dried in vacuum oven at 60 oC overnight. Synthesis of contrast simonkolleite in contrast aqueous solutions: The contrast products (sample A−H) were synthesized in the corresponding contrast aqueous solutions (solution A−H, see Table 1 for the detailed components) containing equal molarity of HMTA with Zn2+. The synthetic details were referenced to that of multilayered simonkolleite above. All reagents used here were purchased except for the as-prepared Zn(EDAC)2, Zn(BDAC)2, Zn(ODAC)2.



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Table 1. The detailed components of the contrast solutions and corresponding samples.

Contrast samples

Contrast solutions

The detailed components of contrastive solutions

Sample A

Solution A

50 mM Zn(Ac)2

Sample B

Solution B

50 mM ZnCl2

Sample C

Solution C

50 mM Zn(Ac)2, 100 mM NaCl

Sample D

Solution D

50 mM ZnCl2, 100 mM NaAc

Sample E

Solution E

50 mM Zn(Ac)2, 100 mM DTAC∗

Sample F

Solution F

50 mM Zn(EDAC)2

Sample G

Solution G

50 mM Zn(BDAC)2

Sample H

Solution H

50 mM Zn(ODAC)2

∗ Dodecyl trimethyl ammonium chloride Fabrication of the electrodes for three electrode supercapacitors: The slurries were homogenized by active materials (pure simonkolleite powder), acetylene black, and polyvinylidene fluoride (PVDF) with a mass ratio of 8:1:1 in N-methyl-2-pyrrolidone (NMP). The electrodes were prepared by coating the homogenous slurries onto the nickel foam with size of 1×1 cm2 and then pressed at a pressure of 2 MPa after keeping under vacuum at 65 oC for 2 h, and subsequently dried at 65 oC for 10 h under vacuum. The mass loading of each piece was controlled to be 1.2~1.5 mg cm−2. The three electrode supercapacitors were assembled using as-formed electrode as the working electrode and a commercial Pt foil (with a size of 1×1 cm2) as the counter electrode as well as Ag/AgCl (3 M KCl) as the reference electrode in 2 M KOH aqueous electrolyte. Material and electrode characterization: The powder X-ray diffraction (XRD) was taken to record the crystal structures on a Rigaku Smartlab 3 using the copper Kα radiation (λ = 1.54 Å).


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The morphologies of synthesized products were observed by scanning electron microscopy (SEM, FEI) and transmission electron microscopy (TEM, JEM-2100). Nitrogen sorption isotherms were recorded on a 3H-2000PS1. The charge storage and transfer behaviours were identified by the electrochemical workstation (Gamry Reference 600), using cyclic voltammetry (CV) with different scan rates (5~100 mV S−1) from 0 to 0.5 V, and electrochemical impedance spectroscopy (EIS) with frequency range from 10−1 to 105 Hz at 5 mV bias voltage. The discharge/charge performance was detected on a Land automatic battery tester in a range of 0−0.4 V. RESULTS AND DISCUSSION The crystal structure of the product is characterized by XRD as shown in Figure 2a. The identification of all diffraction peaks could be absolutely indexed to Zn5(OH)8Cl2·H2O (JCPDS 07-0155), indicating that the crystallographic phase of the product is assigned to pure rhombohedral simonkolleite with a strong preferential orientation along (003) plane. However, simonkolleite reported in the literature is always accompanied by impurity peaks of ZnO or absence of several planes compared with standard diffraction peaks.4, 18, 26, 28 As a representative lamellar structure, simonkolleite contains brucite-like zinc hydroxide layers which consist of reticular planes of hexagonally ordered octahedrally coordinated zinc cations and tetrahedrally coordinated zinc cations occupied above and below the vacant octahedral units.29 And these layers perpendicular to the c-direction are bridged by chloride anions and water molecules. The morphology of the as-synthesized sample is imaged by SEM (Figure 2b). The substrate is densely covered with a large quantity of microscopic bulks of which the majority are nearly hexagonal in shape with size distribution of ~10 µm on the top view. The high magnification SEM images (Figure 2c,d) clearly reveal the good monodispersity of 3D hierarchical multilayered



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simonkolleite with the whole thickness in a range of 3~5 µm. This novel morphology is generated by ordered interdigitation of secondary nanosheet growth from an existing nanosheet or delamination of the lamellar simonkolleite structure to form much complex off-shooting nanosheets, giving each layer with an average thickness of ~10 nm. It is common to see that the interdigitation core is located at the very center of each representative 3D bulk (Figure 2b) and multiple dislocation centers are significantly observed on the top layers (Figure 2c,d).

Figure 2. XRD pattern of simonkolleite (a), SEM images of overview (b), top view (c) and side view (d) of simonkolleite morphology, TEM image (e) and corresponding selected-area electron diffraction (SAED) pattern (f) of a typical simonkolleite structure. Unlike other layered zinc hydroxides partially converted into ZnO under TEM observation,5 the multilayered simonkolleite has a good stability under the high energy electron beam without any obvious damage or degradation (Figure 2e). The hexagonal geometry of this material is also


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displayed obviously in TEM image and the multilayered structure is further supported by the distinctly contrast contours with quasi-sharp edges at the apex of each other within the layers. The SAED pattern keeps the single crystal feature well even under the convergent electron beam, indicating the high crystallinity of the multilayered simonkolleite, which is consist with the XRD analysis (Figure 2f). The beam direction as expected for top down observation is along the c axis orthogonal to the layers, giving a [001] zone axis pattern with a typical net hexagonal symmetry and a possible crystallographic preferential orientation.30 The morphology evolution of simonkolleite at different stages is further investigated to understand the formation of 3D multilayered structure (Figure 3). As shown in Figure 3a and S1a, most percentage of the initial product exhibits Taegeuk-like nanoplate structure, indicating a screw dislocation tendency. With time increasing, the screw dislocation spirals are easy to observe on these relatively thin nanoplates with single dislocation cores located at the near centers, while multiple dislocation centers and the delamination of the nanosheets are observed on the large and much complex nanoplates (Figure 3b and S1b). When further prolonging the reaction time, the morphologies of the product tend to uniformity and come as hexagons and triangles as well as truncated triangles, which also reveal the multiple dislocation step edges as well as an obvious increment in the layers and thickness and thus lead to the formation of 3D multilayered structure (Figure 3c and S1c). Consequently, the crystal growth of simonkolleite follows the screw dislocation-driven growth theory,31 which is further identified by TEM images of the nanosheets at early growth stages as shown in Figure 3d,e. Abundant contrast contours called “spider contours” are clearly seen in both of the nanosheets, which are believed to be associated with the strain fields of dislocations within the nanosheets. Furthermore, the secondary nanosheet growth accompanied



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by delamination from an existing nanosheet are also observed expectantly (Figure 3e).

Figure 3. SEM images of simonkolleite obtained at different treatment times: (a) 1h, (b) 2h, and (c) 3h. (d) and (e) TEM images and corresponding SAED patterns of simonkolleite nanosheets at early growth stages. On the basis of our knowledge, the screw dislocation-driven growth can explain the formation of 2D nanoplates. And these nanoplates with huge width-to-thinckness ratios would be formed with only dislocation cores located at the very center of themselves in an ideal synthetic solution. However, influenced by the complex solution environments, more complex and defective


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nanoplates with multiple dislocation centers and off-shooting nanosheets would be also formed. Therefore, controlling the factors that influence dislocation-driven growth process could eventually control the final crystal morphologies. Considering the complex ion units consisted in our system, ion-adjusted experiments would be designed and carried out to analyze the main factors influencing the forming multilayered 3D simonkolleite, such as chloride ion, acetate, long alkyl chain and quaternary ammonium groups. When only Zn(CH3COO)2 was used as precursor, obtained belt-like sample A (Figure 4a) is assigned to layered zinc hydroxide acetate rather than simonkolleite (Figure 4c). In contrast to sample A, sample B synthesized by the only precursor ZnCl2 exhibits 2D hexagon nanoflakes (Figure 4b) and might be simonkolleite with detective crystal structure deduced from only few asterisk-marked diffraction peaks matched well (Figure 4c). Sample C prepared by Zn(CH3COO)2 and NaCl gives growth characteristic of a small percentage of bowl-like morphology (Figure 4d) and improved crystallinity of simonkolleite (Figure 4f). Prospectively, sample D obtained from ZnCl2 and CH3COONa resembles sample C in morphology and crystalline due to the almost identical ion-system (Figure 4e,f). Sample E (precursors DTAC and Zn(CH3COO)2) exhibits 3D structure stacked by several calathiform nanosheets and its XRD pattern gives the same features as sample C and D (Figure 4g,i). Using Zn(EDAC)2 precursor, despite the morphology being exhibited as hexagon nanosheets with poor dispersion, the product sample F indicates the well crystallized phase as the same as the multilayered simonkolleite (Figure 4f,i). These morphologies observed in each sample are the majority morphologies even in the low-magnification SEM images except for sample C and D (Figure S2). From these descriptions, it could be concluded that the chloride ions play decisive role in the formation of simonkolleite crystalline, that is, they have absolutely



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competitive advantage to act as the interlayer anions. The free acetate groups introduced in synthetic system have a stimulative effect on the crystal structure, and make contribution to the appearance of curled concave in morphology.32 The multilayer and monodispersion tendency of nanoflakes benefits from the long alkyl chains which do little help to promotional crystallinity of simonkolleite. The perfect crystallinity only could be realized when acetate and quaternary ammonium groups are covalently linked rather than simply mixed.

Figure 4. SEM images and XRD patterns of sample A and B (a−c), SEM images and XRD patterns of sample C and D (d−f), SEM images and XRD patterns of sample E and F (g−i).


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Scheme 1. The illustration of the influence of different ions in solution for forming varied morphologies. Having taken into account above the results and analyses, the ion influences experienced in the hydrothermal system are tentatively proposed. As illustrated in Scheme 1, the presence of different ions in synthetic solution influence the formation of new step growth on the basic nanolayers, and thus determine the finally varied morphologies. In the initial stage, the positively charged zinc



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hydroxide layers ([Znoct3(OH)8Zntetr2(H2O)2]2+)33 are formed with the continuous release of OH− anions provided by self-hydrolysis of HMTA34 and balanced by Cl− anions which are absolutely competitive as intercalated species to combine the neighboring zinc hydroxide layers. Consequently, the simonkolleite units are incubated in solution and readily serve as nuclei for further crystal growth to form the subsheets as basic growth layers. Complying with the screw dislocation-driven growth, at the center of the basic growth layers are the screw dislocation cores of which the dislocation edges will favor the filling of new growth units.35 The continuously generated simonkolleite units not only act as nuclei in themselves but also are readily gathered to the dislocation spirals to create new steps pile up. Undoubtedly, the surplus simonkolleite units are also gathered to the outer edges of the basic growth layers to spread in plane. In the relatively identical solution like solution B, the aggregations of simonkolleite unites on basic growth layers are minimally influenced by ion environment and thus guarantee the formation of monolayerd nanoplates (Figure 4b and S2b). In acetate ions-presented solution, such as solution C and D, acetate ions easily absorb onto the surfaces of the simonkolleite unites by the coordination with tetrahedrally coordinated zinc cations. Despite the absorption of acetate ions, the simonkolleite units gathered to the dislocation spirals are still within the van der Waals contact distance of the basic growth layers, leading to the direct step growth on the basic layers and thus forming monolayerd nanosheets. Occasionally, too much adsorption of acetate ions might overcome the van der Waals interaction between the aggregated simonkolleite units and the basic growth layers to induce the delamination from the nanosheets. This situation explains the small percentage of bowls with several layers in sample C and D (Figure S2c,d). When acetate ions and positive charged long-chain quaternary ammonium groups are both presented in the solution (solution E), the surfaces of


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simonkolleite units are capped not only by acetate ions through coordination with tetra-coordinated zinc atoms but also by long-chain quaternary ammonium groups via electrostatic attraction, most likely, with the positive head groups (−CH2(CH3)3N+)36, 37 bound to the surface and long alkyl chains toward the outside. Owing to the non-directionality of the electrostatic attraction, the orientation of the long alkyl chains are uncertain, that is to say, the angles between the chains and the simonkolleite unit surfaces could be changed easily. Only in the case of an appropriate angle of tilt most likely a more perpendicular orientation, the gathered simonkolleite units could not approach within the van der Waals contact distance of the basic growth layers due to the steric hindrance arisen from the long alkyl chains, and thus lead to the delamination from the nanosheets (Figure 4g and S2e). Different from the acetate ions and positive charged long-chain quaternary ammonium groups being separated in solution E, they are bounded together covalently to form much complex ions in our system and show intriguing “Y” structures with the head-groups of (−CH2(CH3)2N+Ac−)38 carrying both negative and positive charges and the tails of long alkyl chains. These complex ions readily adsorb on the newly generated simonkolleite units through a combination of strong coordination and electrostatic attraction attributed to covalently bounded acetate ions and quaternary ammonium groups, guaranteeing the ordered orientation of long alkyl chains with suitably titled angles. In this case, it is much easier for gathered simonkolleite units to overcome the van der Waals attraction of the basic growth layers, resulting in a high chance of delamination (Figure 1b,c). Curiously, monolayered simonkolleite nanosheets are obtained when the long alkyl chains consisted in the “Y” structure are replaced by short alkyl chains in solution F (Figure 4h and S2f). This result suggests that the delamination probability depends on both ordered orientation and length of the alkyl chains. It is further confirmed by the significantly increased



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layers versus increased length of the alkyl chains (Figure S3).

Figure 5. (a) N2 absorption/desorption isotherms of multilayered and monolayered simonkolleite. The inset is pore distribution of monolayered and multilayered simonkolleite. CV curves of (b) multilayered simonkolleite and (c) monolayered simonkolleite at various scan rates. Galvanostatic discharge curves of (d) multilayered simonkolleite and (e) monolayered simonkolleite at different current densities. (f) Specific capacitance calculated from discharge curves of multilayered and monolayered simonkolleite. Cyclic performance and coulombic efficiency of (g) multilayered simonkolleite and (h) monolayered simonkolleite at a current density of 5 A g−1 for 2000 cycles. (i) Nyquist plots of multilayered and monolayered simonkolleite electrodes before and after cycling. The inset shows the high frequency region and equivalent circuit.


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For electrode materials, the high specific surface areas and suitable pore structures are very important.39-42 Figure 5a contrasts N2 absorption/desorption isotherms and pore distributions of monolayered and multilayered simonkolleite, respectively, giving higher specific surface area and pore volume of multilayered simonkolleite than those of monolayered simonkolleite (Table S1). In other words, multilayered simonkolleite is more suitable as the electrode material for supercapacitor. In order to investigate the advantages of multilayered simonkolleite, the electrochemical performance of monolayered and multilayered simonkolleite electrodes are compared. As shown in Figure 5b,c, the observed Faradaic redox peaks are arisen from the intercalation/deintercalation of K+ from the electrolyte into simonkolleite, which contribute to the capacitance of the simonkolleite electrode.19,

43

Compared with monolayered simonkolleite,

multilayered simonkolleite preserves more well-defined redox peaks at high scan rates, indicating smaller polarization and faster electrode kinetics. As displayed in Figure 5d−f, multilayered simonkolleite releases a higher capacity at each current density, suggesting a better rate capability. The cyclic stability is also an important characteristic for electrodes. The multilayered simonkolleite exhibits a high capacity of 240 F g−1 with a capacitance retention of over 97.1 % after 2000 cycles, which is about 40 % higher than that of monolayered simonkolleite (Figure 5g,h). EIS measurement was explored to further understand the kinetics of the electrodes as shown in Figure 5i. The multilayered and monolayered simonkolleite possess almost the same features of Niquist plots before cycling. However, the plot of multilayered simonkolleite after 2000 cycles consists smaller semicircle at high frequency and more perpendicular line at low frequency, reflecting smaller charge transfer impedance and lower diffusion resistance for ions. These comparisons demonstrate the advantages of the multilayered simonkolleite as electrode material with high capacitance, good



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rate capability and cyclic stability. The enhanced electrochemical performance of the multilayered simonkolleite could be attributed to the following aspects: (1) The high specific surface area and pore volume provide enough active sites and mass transfer channels. (2) The 3D multilayered simonkolleite consists of ultrathin nanosheets, which significantly shorten electrolyte diffusion pathways. CONCLUSION In summary, we have reported a hydrothermal method for preparation of monodisperse simonkolleite with multilayered 3D structure composing of 2D nanoplates. Successful synthesis of this novel structure greatly depends on the unique molecular structure of the counter ion of Zn2+, namely DDAC−, which possesses numerous groups, such as chloride ion, long alkyl, acetate and quaternary ammonium group being covalently bound. Ion-adjusted experiments were designed and carried out to analyze the main factors of each group influencing the formation of multilayered 3D simonkolleite. These experiments suggest that the presence of the chloride ions is an essential prerequisite for forming simonkolleite. The covalently bonded acetate ions and long-chain quaternary ammonium groups could absorb on the surfaces of gathered simonkolleite unites with ordered orientation to promote delamination of the basic growth nanosheets, thus leading to propagate multilayered 3D structure. This interpretation is mainly rooted in the screw dislocation-driven growth theory. Additionally, the multilayered 3D simonkolleite as electrode material obtains improved electrochemical performance with high capacitance, good rate capability and cyclic stability in compare with commonly 2D simonkolleite nanosheets. Furthermore, the method utilizing the complex salt as both precursor and morphological directing agent could be spreading to synthesis of other metal hydroxides with well-shaped 3D morphologies.


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ASSOCIATED CONTENT Supporting Information The Supporting Information is available free of charge. Synthetic procedure and characterization of DDAAC, EDAAC, BDAAC and ODAAC, SEM images for simonkolleite, 1H NMR spectra for EDAAC, BDAAC, ODAAC and DDAAC. Accession Codes CCDC 1445616 contains the supplementary crystallographic data for this paper. These data can be obtained free of charge via www.ccdc.cam.ac.uk/data_request/cif, or by emailing [email protected], or by contacting The Cambridge Crystallographic Data Centre, 12, Union Road, Cambridge CB2 1EZ, UK; fax: +44 1223 336033. AUTHOR INFORMATION Corresponding Author *E-mail: [email protected] (Y Shao) *E-mail: [email protected] (Y Sun) ACKNOWLEDGMENT This work was financially supported by the Key University Science Research Project of Anhui Province (KJ2017A712, KJ2017A713), Foundation of Anhui Provincial Teaching Team (2015jxtd113), National Basic Research Program of China (2013CB932902). REFERENCES (1) Kasai, A.; Fujihara, S. Inorg. Chem. 2006, 45, 415-418. (2) Poul, L.; Jouini, N.; Fiévet, F. Chem. Mater. 2000, 12, 3123-3132. (3) Delahaye, E.; Eyele-Mezui, S.; Diop, M.; Leuvrey, C.; Rabu, P.; Rogez, G. Dalton Transactions



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For Table of Contents Use Only

Table of Contents Graphic

Synopsis A unique multilayered three-dimensional simonkolleite with good monodispersity was successfully synthesized by assistance of an ionized long-chain quaternary ammonium carboxylic acid.

Controllable Growth of Monodisperse Multilayered 3D Simonkolleite and Its Supercapacitor Activity Bo Song,† Xia Cui,† Yun Xie,† Shisu Cheng,† Yijiang Shao,*,† and Yueming Sun*,‡


Controllable Growth of Monodisperse Multilayered Three-Dimensional

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