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Jan 24, 2017 - College of Materials Science and Technology, Nanjing University of ... Design of an interface to arouse interface polarization is an ef...
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Interface Polarization Strategy to Solve Electromagnetic Wave Interference Issue Hualiang Lv, Yuhang Guo, Guanglei Wu, Guangbin Ji, Yue Zhao, and Zhichuan J. Xu ACS Appl. Mater. Interfaces, Just Accepted Manuscript • DOI: 10.1021/acsami.6b16223 • Publication Date (Web): 24 Jan 2017 Downloaded from http://pubs.acs.org on January 27, 2017

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Interface Polarization Strategy to Solve Electromagnetic Wave Interference Issue Hualiang Lv,a,b Yuhang Guo,c Guanglei Wud, Guangbin Ji*a Yue Zhaoa, Zhichuan J.Xu*b a

College of Materials Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing 211100, P. R. China. b

School of Materials Sciences and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore c

School of Materials Science and Engineering, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu,212003,China

d

Institute of Materials for Energy and Environment, State Key Laboratory Breeding

Base of New Fiber Materials and Modern Textile, College of Materials Science and Engineering, Qingdao University, Qingdao 266071, P. R. China

*Corresponding Author: Prof. Dr. Guangbin Ji. Tel: +86-25-52112902; Fax: +86-25-52112626 E-mail: [email protected]

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Abstract Design of interface to arouse interface polarization is an efficient route to attenuate high frequency electromagnetic wave. Meanwhile, the attenuation intensity is highly related to the contact area. To achieve the stronger interface polarization, growing metal oxide granular film on graphene with larger surface area seems to be an efficient strategy due to the high charge carrier concentration of graphene. This study is devoted to fabricate the film-like composite by a facile thermal decomposition method and investigate the relationship of contact area, polarization intensity as well as the type of metal oxide. Due to the high-frequency polarization effect, these composites presented excellent electromagnetic wave attenuation ability. As concluded, the optimal effective frequency bandwidth (fE) of graphene (GN)/metal oxide was close to 7.0 GHz at a thin coating layer of 2.0 mm. Meanwhile, corresponding reflection loss (RL) value was nearly -22.1 dB. Considered the attenuation mechanism, interface polarization may play a key role on the microwave absorbing ability. Key words: Interface polarization; metal oxide granular film; electromagnetic interference; effective absorption frequency; contact area. 1. Introduction High-frequency electromagnetic wave absorber can convert unwanted high frequency electromagnetic wave (>GHz) into thermal energy.1-3 The polarization intensity of electromagnetic absorber is the primarily dielectric loss form to eliminate electromagnetic interference (EMI) issue.4 Except for interface polarization, other

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attenuation forms at high frequency (including atomic, ionic as well electron polarization) could only work at lower frequency region (< GHz).5-6 To achieve good electromagnetic absorption performance, taking full advantage of the interface polarization is an efficient strategy. Core-shell structure at the early stage had been widely studied due to its interface such as Fe3O4 based composites (e.g.: Fe3O4@CuSiO3,7 Fe3O4@C,8 Fe3O4@TiO29 Fe3O4@SiO2@NiO10). Other similar absorbers, like MnO2@Fe,11 and Fe@SiO212 etc. also have been developed in recent years. Besides, much effort has been devoted to combining metal oxide with large surface of graphene with strong interface polarization. Various graphene based absorbers with enhanced electromagnetic absorption performance have been studied, such as graphene/Fe,13 graphene/SiC,14 and graphene/carbon15. For example, Cao et al. prepared graphene/MnFe2O4/PVDF composite and got the reflection loss (RLmin) value of -29.0 dB with an effective frequency bandwidth (fE) of 4.88 GHz.16 Huang et al. investigated the microwave absorption of graphene/CoFe2O4 and obtained the RLmin of -44.1 dB with a fE value of 4.7 GHz.17 RLmin in the electromagnetic absorption field refers to the absorption intensity and only reflection loss value less than -10 dB is regarded as a desired value (corresponding to more than 90 % of absorption and attenuation).18 Considered the commercial application, an ideal absorber needs to own a broader effective absorption frequency bandwidth (RLmin50)41 will result in the unmatched ratio between absorber to free space. In this case, most electromagnetic wave will reflect from the surface of absorption layer and can not enter into the absorption layer. On the contrary, if absorber owns a quite smaller ε' value (like SiO2, 2-5),42 electromagnetic wave penetrates the coating layer easily and also is not favor for attenuation. Usually, the ε' value among 10-30 is considered to an ideal region. Among these composites, GN/Co0.5Ni0.5Fe2O4 exhibits the highest ε' value at the whole frequency region while GN/Fe0.5Ni0.5Co2O4 is lowest. But at a high frequency region 10-18 GHz, their difference in ε' values are smaller. According to the electromagnetic absorption mechanism, ε'' represents the dielectric loss ability. Commonly, a higher ε'' value ensures a stronger attenuation electromagnetic wave ability. As can be seen from the Figure 8b, these ε'' values present an apparent incensement at high frequency. In particular, GN/NiFe2O4/CoNiO2 possesses a smaller value at almost 2-12 GHz than GN/Co0.5Ni0.5Fe2O4. Hence, the ε'' value of GN/NiFe2O4/CoNiO2 is even larger than GN/Co0.5Ni0.5Fe2O4. Generally, the enhanced of ε'' is mainly originated from multiple polarization effects, liking electron, ionic, dipolar and interface polarization.43-44 Whereas, electronic and ionic polarization forms are ruled out because these two kinds of polarization usually happens at ultraviolet or IR frequency region.45 According to literature, this increasing phenomenon in high frequency may originate from the interface and dipolar polarization effects. In this study, film-shape of metal

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oxide makes big contact area with graphene. Interface polarization effect happens at the interface of graphene and metal oxide, which reflects in the increase of ε'' values.46 Excepting for the interface polarization between metal oxide and graphene, different crystal plane between NiFe2O4 and CoNiO2 also play a key role on the dielectric loss behavior. As a result, GN/NiFe2O4/CoNiO2 shows the largest ε'' value at high frequency. Figure 9c and d show their magnetic loss ability. At 2-18 GHz, three absorbers present the same order at µ' and µ'' which are due to their magnetization values. In detailed, GN/NiFe2O4 owns the biggest µ' and µ'' values while GN/Co0.5Ni0.5Fe2O4 is lowest. It should be noted that the bigger µ' and µ'' have a contribution on the impedance matching behavior. In addition, partial incoming electromagnetic energy may be consumed in the forms of natural resonance, eddy current as well as domain wall resonance. Of course, the contribution of domain wall resonance is weakly at microwave frequency.47 But if the eddy current effect occurs at these absorbers, the C0 (C0 = µ″(µ′)-2f−1 = 2πµ0σd2/3) will be a constant. It can be deducted from Figure 10 that these C0 values change with the increasing frequency which was ascribed to the unique granular film-like structure (See the insert of Figure 10). Hence, the magnetic loss of these absorbers is primarily come from the natural resonance which several peaks at GN/NiFe2O4/CoNiO2 and GN/Co0.5Ni0.5Fe2O4 absorbers. However, due to the quite smaller µ″ value, GN/Co0.5Ni0.5Fe2O4 almost shows obvious magnetic loss ability. Thus, we can make a conclusion that the excellent electromagnetic attenuation ability may come from the interface polarization. Besides, for GN/GN/NiFe2O4/CoNiO2 and GN/Co0.5Ni0.5Fe2O4 absorbers, natural

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resonance also plays a key role on the attenuation of electromagnetic energy. Because of the bigger µ′ and µ′' values, GN/Co0.5Ni0.5Fe2O4 presents the best electromagnetic absorption properties. To investigate the influence of contact area on the interface polarization, the contrast experiments have been done by increasing the initial content of graphene. In this way, the contact area of graphene/metal oxide will make a decrease. To rule out the influence of magnetic loss, the interface of graphene and Fe0.5Ni0.5Co2O4 were investigated. As we know, for graphene/Fe0.5Ni0.5Co2O4 sample, the attenuation electromagnetic ability was primarily resulted from the dielectric loss since the weakly magnetic properties. Nevertheless, the interface polarization intensity determined the high frequency dielectric loss ability. Figure 11 a-d displayed the schematic illustration and TEM images of the graphene/Fe0.5Ni0.5Co2O4 sample with initial graphene of 20 and 30 mg. Remarkably, the contact area decreased as increasing

of

the

graphene

graphene/Fe0.5Ni0.5Co2O4-20

content.

presented

In the

this

case,

stronger

we

considered

interface

that

polarization

performance as compared to the graphene/Fe0.5Ni0.5Co2O4-30. So, corresponding graphene/Fe0.5Ni0.5Co2O4-20 would achieve the better electromagnetic absorption properties. Figure 11 e-f showed the reflection loss spectrum of these two samples. At 1.5 mm, the fE value of graphene/Fe0.5Ni0.5Co2O4-20 was nearly 3.0 GHz while another graphene/Fe0.5Ni0.5Co2O4-20 sample was even no more than 2.0 GHz. At other thickness (2.0 and 2.5 mm), the fE value of graphene/Fe0.5Ni0.5Co2O4-20 also larger than graphene/Fe0.5Ni0.5Co2O4-20. This result was consistent with our

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assumption. Subsequently, their high frequency (10-18 GHz) ε'' values including graphene were given in the Figure 11 g-i. Pure graphene at high frequency usually presented the decrease tendency (without peak). This is due to the resistivity value (ρ) of graphene was almost a constant value and do not response to the external electromagnetic filed. Therefore, increase of the frequency will result in the smaller ε'' value according to the free electron theory:49 ε''=1/πρεof (3) Whereas, obvious peak can be observed for the graphene/Fe0.5Ni0.5Co2O4 samples. Interface polarization generally happened at one certain frequency point. The most accepted viewpoint that the interface polarization could affect the ρ value and thus reflect in the peak at high frequency region. Also, the appearance frequency of interface polarization is related to the types of interface. In Figure 11 h and i, the ε'' value of graphene/Fe0.5Ni0.5Co2O4-20 increases from 4.2 to 4.8 (∆ε'' =0.6) and larger than that of graphene/Fe0.5Ni0.5Co2O4-30 (∆ε'' =0.2). The larger ∆ε'' value represented the stronger interface polarization behavior. Besides, the relaxation behavior also been considered to prove the intensity of this interface polarization. Generally, the relaxation process was associated with the Cole-Cole semicircle. Deeply, the relative complex permittivity can be drawn by the above equations:50

ε =ε + r



ε −ε = ε ' − jε ' ' 1 + j 2πfτ s



(4)

Where εs, ε∞, τ are static permittivity, relative dielectric permittivity at high-frequency limit, and polarization relaxation time, respectively. Therefore, the ε' and ε'' can be calculated according to the following equations. 15

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ε s − ε∞ 1 + (2πf )2τ 2

(5)

2πfτ (ε s − ε ∞ ) 1 + (2πf ) 2τ 2

(6)

ε ′ = ε∞ +

ε ′′ =

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Based on the equation (5) and (6), the ε'-ε'' can be expressed as above:

(ε ′ − ε ∞ )2 + (ε ′′)2 = (ε s − ε ∞ )2

(7)

If the plot of ε'-ε'' presented semicircle-like, this is called as the Cole-Cole semicircle. Each Cole-Cole semicircle refers to one Debye relaxation process. As observed in Figure 11g-k, One Cole-Cole semicircle could be found at the grahene/Fe0.5Ni0.5Co2O4-20 composite. This Cole-Cole semicircle represented the Debye relaxation process which attributed to the interface polarization effect. Due to the

weak

interface

polarization

intensity,

the

Cole-Cole

semicircle

of

grahene/Fe0.5Ni0.5Co2O4-30 is not apparent. In addition, we also investigated the influence of the granular film-like structure on the microwave absorption properties. By annealing the graphene/FeCoNi precursor at higher temperature (700 oC), the granular film-like of Fe0.5Ni0.5Co2O4 was transferred into particle-like with the size ranged in 50-100 nm, as seen in the TEM image (Fig S2-a). At identical condition, the reflection loss value at 1.5 mm is even less than -10 dB (Figure S-2b). At 2.0 mm, the reflection loss value only reaches to -11.0 dB (Figure S-2c). Obviously, the sample shows the poor absorption property. The imaginary part of permittivity value in Figure S-2d reveals that the peak at high frequency is weak (appear at ~14.0 GHz), which was probably due to the weak interface polarization intensity.

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4. Conclusions In this study, we adopted an effective strategy to grow metal granular oxide film on graphene. By adjusting the atomic ratio of Fe/Co/Ni, various films could be achieved, liking Fe0.5Ni0.5Co2O4, NiFe2O4/CoNiO2 and Co0.5Ni0.5Fe2O4. These composites presented improved attenuation electromagnetic wave ability at a thin coating layer. For example, at 2.0 mm, the optimal reflection loss value could reach to -33.1 dB. The maximum fE value was up to 7.0 GHz. This excellent electromagnetic absorption performance could be attributed to the interface polarization effect. Supporting Information The Supporting Information is available free of charge on the ACS Publications website at DOI: TEM images of the graphene/metal oxide precursor (Fe/Co/Ni=2:1:2) prepared at 8 and 16 h, TEM images of the graphene/Fe0.5Ni0.5Co2O4 obtained at 700 oC, the reflection loss curves of the graphene/Fe0.5Ni0.5Co2O4 sample calculated at 1.5 mm and 2.0 mm, the imaginary part of permittivity of the graphene/Fe0.5Ni0.5Co2O4. Acknowledgments Financial supports from the National Natural Science Foundation of China (No.: 11575085), the Funding for Outstanding Doctoral Dissertation in NUAA (No.: BCXJ15-09), the Qing Lan Project, Six talent peaks project in Jiangsu Province (No.: XCL-035) and the Project also Founded by the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD) are highly acknowledged.

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References [1] Liu, Q.H.; Cao, Q.; Bi, H.; Liang, C.Y.; Yuan, K.P.; She, W.; Yang, Y.J.; Che, R.C. CoNi@SiO2 @TiO2 and CoNi@Air@TiO2 Microspheres with Strong Wideband Microwave Absorption. Adv. Mater. 2016, 28, 486-490. [2] Wen, B.; Cao, M.S.; Lu, M.M.; Cao, W.Q.; Shi, H.L.; Liu, J.; Wang, X.X.; Jin, H.B.; Fang, X.Y.; Wang, W.Z.; Yuan, J. Reduced Graphene Oxides: Light-Weight and High Efficiency Electromagnetic Interference Shielding at Elevated Temperatures. Adv Mater. 2014, 26, 3484-348489. [3] Lv, H.L.; Ji, G.B.; Zhang, H.Q.; Li, M.; Zuo, Z.Z.; Zhao, Y.; Zhang, B.S.; Tang D.M.; Du, Y.W. CoxFey@C Composites with Tunable Atomic Ratios for Excellent

Electromagnetic

Absorption

Properties.

Sci.

Rep.

2015,

5,

18249-18259. [4] Feng, W.; Wang, Y.M.; Chen, J.C.; Wang, L.; Guo, L.X.; Ouyang, J.H.; Jia, D. Z.; Reduced Graphene Oxide Decorated with In-situ Growing ZnO Nanocrystals: Facile Synthesis and Enhanced Microwave Absorption Properties. Carbon. 2016, 110, 52-60. [5] Lv, HL.; Guo, YH.; Yang ZH.; Cheng, Y.; Wang (Paul) LY.; Zhang BS.; Zhao, Y.; Ji GB. A Brief Introduction to the Fabrication and Synthesis of Graphene Based Composites for the Realization of Electromagnetic Absorbing Materials. J. Mater. Chem. C. 2017, DOI:10.1039/c6tc03026b. [6] Zhang, X.F.; Li, Y.X.; Liu, R.G.; Rao, Y.; Rong, H.W.. High-Magnetization FeCo Nanochains with Ultrathin Interfacial Gaps for Broadband Electromagnetic

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Page 19 of 34

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

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Wave Absorption at Gigahertz. ACS Appl. Mater. Interfaces. 2016, 8, 3494-3498. [7] Liu, J.W.; Cheng, J.; Che, R.C.; Xu, J.J.; Liu, M.M.; Liu, Z.W. Synthesis and Microwave Absorption Properties of Yolk–Shell Microspheres with Magnetic Iron Oxide Cores and Hierarchical Copper Silicate Shells. ACS Appl. Mater. Interfaces, 2013, 5, 2503–2509. [8] Liu, Y.; Li, Y.N.; Jiang, K.D.; Tong, G.X.; Lv, T.X.; Wu, W.H.; Controllable Synthesis of Elliptical Fe3O4@C and Fe3O4/Fe@C Nanorings for Plasmon Resonance-Enhanced Microwave Absorption. J. Mater. Chem. C. 2016, 4, 7316-7323. [9] Liu, J.W.; Che, R.C.; Chen, H.J.; Zhang, F.; Xia, F.; Wu, Q.S. Wu QS. Microwave Absorption Enhancement of Multifunctional Composite Microspheres with Spinel Fe3O4 Cores and Anatase TiO2 Shells. Small. 2012, 8, 1214-1221. [10] Wang, L, Huang, Y.; Sun, X.; Huang, H.J.; Liu, P.B.; Zong, M.; Wang, Y. Synthesis

and

Microwave

Absorption

Enhancement

of

Graphene@Fe3O4@SiO2@NiO Nanosheet Hierarchical Structures. Nanoscale. 2014, 6, 3157-3165. [11] Lv, H.L, Ji, G.B.; Liang, X.H.; Zhang, H.Q.; Du, Y.W. A Novel Rod-like MnO2@Fe Loading on Graphene Giving Excellent Electromagnetic Absorption Properties. J. Mater. Chem. C. 2015, 3, 5056-5067. [12] Ren, Y.L.; Zhu, C.L.; Zhang, S.; Li, C.Y.; Chen, Y.J.; Gao, P.; Yang, P.P.; Ouyang, Q.Y. Three-dimensional SiO2@Fe3O4 Core/shell Nanorod Array/Graphene Architecture: Synthesis and Electromagnetic Absorption Properties. Nanoscale.

19

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Page 20 of 34

2013,5,12296-12304. [13] Zhu, Z.T.; Sun, X.; Xue, H.R.; Guo, H.; Fan, X.L.; Pan, X.C.; He, J.P. Graphene-carbonyl

Iron

Cross-linked

Composites

with

Excellent

Electromagnetic Wave Absorption Properties. J. Mater. Chem. C. 2014, 2, 6582-6592. [14] Han, M.K.; Yin, X.W.; Duan, W.Y.; Ren, S.; Zhang, L.T.; Cheng, L.F. Hierarchical Graphene/SiC Nanowire Networks in Polymer-derived Ceramics with Enhanced Electromagnetic Wave Absorbing Capability. J. Eur. Ceram. Soc. 2016, 36, 2695-2703. [15] Lv, H.L.; Guo, Y.H.; Zhao, Y.; Zhang HQ.; Zhang, BS.; Ji, G.B.; Xu, J. Z.C. Achieving Tunable Electromagnetic Absorber via Graphene/Carbon Sphere Composites. Carbon. 2016, 110, 130-137. [16] Zhang, X.J.; Wang, G.S.; Cao, W.Q.; Wei, Y.Z.; Liang, J.F.; Guo, L.; Cao, M.S.; Enhanced Microwave Absorption Property of Reduced Graphene Oxide (RGO)-MnFe2O4 Nanocomposites and Polyvinylidene Fluoride. ACS Appl. Mater. Interfaces. 2014, 6, 7471−7478 [17] Zong, M.; Huang, Y.; Zhang, N. Reduced Graphene Oxide-CoFe2O4 Composite: Synthesis and Electromagnetic Absorption Properties. Appl. Surf. Sci. 2015, 345, 272-278. [18] Liu, W.W.; Li, H.; Zeng, Q.P.; Duan, H.N.; Guo, Y.P.; Liu, X.F.; Sun, C.Y.; Liu, H.Z. Fabrication of Ultralight Three-dimensional Graphene Networks with Strong Electromagnetic Wave Absorption Properties. J. Mater. Chem. A. 2015, 3,

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Page 21 of 34

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3739-3747. [19] Wu, HJ.; Wu, GL.;Wang, LD. Peculiar Porous α-Fe2O3, γ-Fe2O3 and Fe3O4 Nanospheres: Facile Synthesis and Electromagnetic Properties. Powder Technol. 2015, 269, 443-451. [20] Lv, H.L.; Liang, X.H.; Ji, G.B.; Zhang, H.Q.; Du, Y.W. Porous Three-Dimensional Flower-like Co/CoO and Its Excellent Electromagnetic Absorption Properties. ACS Appl Mater Interfaces. 2015, 7, 9776-9783. [21] Zhang, Z.L.; Ji, Y.J.; Li, J.; Tan, Q.Q.; Zhong, Z.Y.; Su, F.B. Yolk Bishell MnxCo1 −

xFe2O4

Hollow Microspheres and Their Embedded Form in Carbon for Highly

Reversible Lithium Storage. ACS Appl Mater Interfaces 2015, 7, 6300-6309. [22] Zhao, S.Q.; Liu, T.M.; Javed, M.S.; Zeng, W.; Hussain, S.; Zhang, Y.; Peng, X.H. Rational Synthesis of Cu-doped Porous δ-MnO2 Microsphere for High Performance Supercapacitor Applications. Electrochim. Acta. 2016, 191, 716-723. [23] McIntyre, N. S.; Zetaruk, D. G. X-ray Photoelectron Spectroscopic Studies of Iron Oxides, Anal. Chem. 1977, 49, 1521–1529. [24] Liu, Y.G.; Zhao, Y.Y.; Yu, Y.L.; Ahmad, M.; Sun, H.Y. Facile Synthesis of Single-Crystal Mesoporous CoNiO2 Nanosheets Assembled Flowers as Anode Materials for Lithium-ion Batteries. Electrochim. Acta. 2014, 132, 404-409. [25] Mclntyre, N.S.; Cook, M.G.

X-ray Photoelectron Studies on Some Oxides and

Hydroxides of Cobalt, Nickel, and Copper. Anal. Chem. 1975, 47, 2208-2213. [26] Lv, HL.; Zhang, H.Q.; Ji, G.B. Development of Graphene/g-C3N4 Composite

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with Novel Broad Frequency and Lightweight Feature. Part. Part. Syst. Charact. 2016, 33, 656-663. [27] Lv, H.L.; Ji, G.B.; Liu, W.; Zhang, H.Q.; Du, Y.W. Achieving Hierarchical Hollow Carbon@Fe@Fe3O4 Nanospheres with Superior Microwave Absorption Properties and Lightweight Features. J. Mater. Chem. C. 2015, 3, 10232-10242. [28] Lv, J.L, Zhai, S.R.; Gao, C.; Zhou, N.; An, Q.D.; Zhao, B. Synthesis of Lightweight, Hierarchical Cabbage-like Composites as Superior Electromagnetic Wave Absorbent. Chem. Eng. J. 2016, 289, 261-269. [29] Mishra, M.; Singh, A.P.; Singh, B.P.; Singh, V.N.; Dhawan, S.K. Conducting Ferrofluid: A Performance Microwave Shielding Materials. J. Mater. Chem. A, 2014, 2, 13159-13168. [30] Zhao, B.; Shao, G.; Fan, B.B.; Zhao, W.Y.; Zhang R. Fabrication and Enhanced Microwave Absorption Properties of Al2O3 Nanoflake-coated Ni Core–shell Composite Microspheres. RSC Adv. 2014, 4, 57424-57429. [31] Wang, Y.; Du, Y.C.; Rong, Q.; Tian, C.H.; Xu, P.; Han, X.J. Interfacially Engineered Sandwich-like rGO/Carbon Microspheres/rGO Composite as An Efficient and Durable Microwave Absorber. Adv. Mater. Interfaces. 2016, 3, 1500684-1500692. [32] Yu, M.; Liang, C.Y.; Liu, M.M.; Liu, X.L.; Yuan, K.P.; Cao, H.; Che, R.C. Yolk-Shell Fe3O4@ZrO2 Prepared by A Tunable Polymer Surfactant Assisted Sol-gel Method for High Temperature Stable Microwave Absorption. J. Mater. Chem. C. 2014, 2, 7275-7284.

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[33] Li, X.H.; Feng, J.; Du, Y.P.; Bai, J.T.; Fan, H.M.; Zhang, H.L.; Peng, Y.; Li, F.S. One-pot Synthesis of CoFe2O4/Graphene Oxide Hybrids and Their Conversion into FeCo/Graphene Hybrids for Lightweight and Highly Efficient Microwave Absorber. J. Mater. Chem. A. 2015, 3, 5535-5547. [34] Liu, P.J.; Yao, Z.J.; Zhou, J.T. Preparation of Reduced Graphene Oxide/Ni0.4Zn0.4Co0.2Fe2O4 Nanocomposites and Their Excellent Microwave Absorption Properties. Ceram. Int. 2015, 41, 13409-13416. [35] Zhou, M.; Lu, F.; Lv, T.Y.; Yang, X.; Xia, W.W.; Shen, X.S.; He, H.; Zeng, X.H. Loss Mechanism and Microwave Absorption Properties of Hierarchical NiCo2O4 Nanomaterial. J. Phys. D: Appl. Phys. 2015, 48, 215305-215312. [36] Zong, M.; Huang, Y.; Zhang, N. Reduced Graphene Oxide-Ni0.5Zn0.5Fe2O4 Composite: Synthesis and Electromagnetic Absorption Properties. Mater. Lett. 2015, 145, 115-119. [37] Meng, F.B.; Wei, W.; Chen, J.J.; Chen, X.N.; Xu, X.L.; Jiang, M.; Wang, Y.; Lu, J.; Zhou, Z.W. Growth of Fe3O4 Nanosheet Arrays on Graphene by A Mussel-inspired Polydopamine Adhesive for Remarkable Enhancement in Electromagnetic Absorptions. RSC Adv. 2015, 5, 101121-101127. [38] Yang, Z.W.; Wan, Y.Z.; Xiong, G.Y.; Li, D.Y.; Li, Q.P.; Ma, C.Y.; Guo, R.S.; Luo, H.L. Facile Synthesis of ZnFe2O4/Reduced Graphene Oxide Nanohybrids for Enhanced Microwave Absorption Properties. Mater. Res. Bull. 2015, 61, 292-297. [39] Han, M.K.; Yin, X.W.; Kong, L.; Li, M.; Duan, W.Y.; Zhang, L.T.; Cheng, L.F.

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Graphene-wrapped ZnO Hollow Spheres with Enhanced Electromagnetic Wave Absorption Properties. J. Mater. Chem. A. 2014, 2, 16403-16409. [40] Fu M, Jiao QZ and Zhao Y. Preparation of NiFe2O4 Nanorod-Graphene Composites via An Ionic Liquid Assisted One-step Hydrothermal Approach and Their Microwave Absorbing Properties. J. Mater. Chem. A. 2013, 1, 5577-5587. [41] Zhong, B.; Tang, X.H.; Huang, X.X.; Xia, L.; Zhang, X.D.; Wen, G.W.; Chen, Z. Metal-Semiconductor Zn/ZnO Core-shell Nanocables: Facile and Larger-scale Fabrication,

Growth Mechanism, Oxidation Behavior, and Microwave

Absorption Performance. CrystEngComm, 2015, 17, 2806-2814. [42] Lv, H.L.; Ji, G.B.; Zhang, H.Q.; Du, Y.W. Facile Synthesis of A CNT@Fe@SiO2 Ternary Composite with Enhanced Microwave Absorption Performance. RSC Adv. 2015, 5, 76836-76844. [43] Liu, T.; Zhou, P.H.; Xie, J.L.; Deng, L.J. Electromagnetic and Absorption Properties of Urchin-like Ni Composites at Microwave Frequencies. J. Appl. Phys. 2012,111,093905-093910. [44] Deng J.S.; Lei, Y.H.; Wen, S.M.; Chen, Z.X.; Modeling Interactions between Ethyl Xanthate and Fe/Cu Ions Using DFT/B3LYP Approach. Inter. J. Miner Process. 2015, 140,43-49. [45] Zhang, X.; Shen, Y.; Xu, B.; Zhang, Q.H.; Gu, L.; Jiang, J.Y.; Ma J.; Lin, Y.H.; Nan, C.W. Giant Energy Density and Improved Discharge Efficiency of Solution-Processed Polymer Nanocomposites for Dielectric Energy Storage. Adv Mater.2016, 9, 2055-2061.

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[46] She, W.; Bi, H.; Wen, Z.W.; Liu, Q.H.; Zhao, X.B.; Zhang, J.; Che, R.C. Tunable Microwave Absorption Frequency by Aspect Ratio of Hollow Polydopamine @ α-MnO2 Microspindles Studied by Electron Holography. ACS Appl Mater Interfaces. 2016, 8, 9782-9789. [47] Lv, H.L.; Zhang, H.Q.; Zhao, J.; Ji, G.B.; Du, Y.W. Achieving Excellent Bandwidth Absorption by A Mirror Growth Process of Magnetic Porous Polyhedron Structure. Nano Res. 2016, 6, 1813-1822. [48] Wang, T.; Wang, H.D.; Chi, X.; Li, R.; Wang, J.B. Synthesis and Microwave Absorption Properties of Fe-C Nanofibers by Electrospinning with Disperse Fe Nanoparticles Parceled by Carbon. Carbon. 2014, 74,312-318. [49] Liu, X. G.; Geng, D. Y.; Meng, H.; Shang, P. J.; Zhang, Z. D. Erratum: Microwave-Absorption Properties of ZnO-Coated Iron Nanocapsules. Appl. Phys. Lett. 2008, 92, 17317-17319. [50] Zhao B.; Zhao, W.Y.; Shao, G.; Fan, B.B.; Zhang, R.; Morphology-Control Synthesis

of

A

Core-Shell

Structured

NiCu

Alloy

with

Tunable

Electromagnetic-Wave Absorption Capabilities. ACS Appl Mater Interfaces.2015, 23, 12951-12960.

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Figure 1. The TEM images of the samples prepared with different atomic ratios of Fe/Co/Ni (a): 1:4:1; (b) 1:2:1, (c) 4:1:1; (d) the element distribution of the sample prepared with the atomic ratio of 2:1:2.

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Figure 2. The XRD patterns of three samples (a) GN/Fe0.5Ni0.5Co2O4; (b) GN/NiFe2O4/CoNiO2; (c)GN/Co0.5Ni0.5Fe2O4; (d) The atomic ratio of Fe/Co/Ni tested by ICP.

Figure 3. XPS data of the GN/NiFe2O4/CoNiO2 sample: (a) Fe 3/2p; (b) Co 3/2p; (c) Ni 3/2p; (d) O 1s.

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Figure 4. Raman spectrum of graphene and graphene/metal oxides.

Figure 5. TEM/HR-TEM images of (a-c) GN/Fe0.5Ni0.5Co2O4; (d-f) GN/NiFe2O4/CoNiO2; (g-h) GN/Co0.5Ni0.5Fe2O4; (i) sample with atomic ratio of 2:1:2 treated at 700 oC. 28

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Figure 6. The magnetization curves of three GN/metal oxides measured at room temperature.

Figure 7. (a) The schematical illustration of the formation process of CS/Fe0.5Ni0.5Co2O4; (b-c) The FE-SEM images of the CS/Fe0.5Ni0.5Co2O4 precursor; (d-e) The TEM images of CS/Fe0.5Ni0.5Co2O4;

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Figure 8. The reflection loss values of three types of graphene composites: (a): GN/Fe0.5Ni0.5Co2O4 GN/Co0.5Ni0.5Fe2O4

(1.5 (1.5

mm);

(b):

mm);

GN/NiFe2O4/CoNiO2 (d):

(1.5

GN/Fe0.5Ni0.5Co2O4

(e):GN/NiFe2O4/CoNiO2 (2.0 mm); (f): GN/Co0.5Ni0.5Fe2O4 (2.0 mm);

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mm); (2.0

(c): mm);

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Figure 9. The electromagnetic parameters of GN/metal oxides (a) µ' value; (b) µ'' value; (c) ε' value; (d) ε'' values.

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Figure 10. The Co-f curves of the three samples.

Figure 11. The interface schematic illustration (a) and TEM image (b) of graphene/Fe0.5Ni0.5Co2O4-20; the interface schematic illustration (c) and TEM image (d)

of

grahene/Fe0.5Ni0.5Co2O4-30;

The

reflection

loss

spectrum

of

grahene/Fe0.5Ni0.5Co2O4-20 (e) and grahene/Fe0.5Ni0.5Co2O4-30 (f); The ε'' curves of graphene (g); grahene/Fe0.5Ni0.5Co2O4-20 (h); and (i) graphene/Fe0.5Ni0.5Co2O4-30; the

Cole-Cole

curves

of

grahene/Fe0.5Ni0.5Co2O4-20

(j)

grahene/Fe0.5Ni0.5Co2O4-30 samples (k).

Table 1. The electromagnetic absorption performance of similar absorbers.

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Sample

RLmin (1.5 mm)

fE (1.5 mm)

RLmin (2.0 mm)

fE (2.0 mm)

Filled Ratio

Ref.

GO/CoFe2O4