Multi-componential metal intercalated graphite hybrids synthesized by co-intercalation polymerization towards highefficient microwave absorptions

Magnetic expanded graphite(EG)hybrids were synthesized by co-intercalation polymerization of aniline together with transition metal ions.Experimental results show that metal ions(Fe,Co,Ni,Cu)and even their mixtures can co-intercalate into graphite interlayers with flexibly controllable ratios and contents.Among these co-intercalation compounds,Fe/Ni-intercalated graphite with a predesigned mole ratio of 1:3 transforms into NiFe_(2)O_(4)/FeNi_(3)@EG during the annealing process.The synthesized magnetic EG hybrids present multiband microwave absorption in C and X bands due to improved impedance match as well as significantly enhanced interfacial polarization relaxation induced by multi-componential metals.The reflection values of−39.1 dB at 6.95 GHz and−25.7 dB at 9.4 GHz are achieved with an ultra-low loading of 5 wt.%.This work provides a flexible approach for tuning the components and structures of magnetic EG hybrids,which may contribute to the development of microwave absorption materials with superior performances.

Precise Thermoplastic Processing of Graphene Oxide Layered Solid by Polymer Intercalation

The processing capability is vital for the wide applications of materials to forge structures as-demand.Graphene-based macroscopic materials have shown excellent mechanical and functional properties.However,different from usual polymers and metals,graphene solids exhibit limited deformability and processibility for precise forming.Here,we present a precise thermoplastic forming of graphene materials by polymer intercalation from graphene oxide(GO)precursor.The intercalated polymer enables the thermoplasticity of GO solids by thermally activated motion of polymer chains.We detect a critical minimum containing of intercalated polymer that can expand the interlayer spacing exceeding 1.4 nm to activate thermoplasticity,which becomes the criteria for thermal plastic forming of GO solids.By thermoplastic forming,the flat GO-composite films are forged to Gaussian curved shapes and imprinted to have surface relief patterns with size precision down to 360 nm.The plastic-formed structures maintain the structural integration with outstanding electrical(3.07×10^(5) S m^(−1))and thermal conductivity(745.65 W m^(−1) K^(−1))after removal of polymers.The thermoplastic strategy greatly extends the forming capability of GO materials and other layered materials and promises versatile structural designs for more broad applications.

Structural regulation of vanadium oxide by poly(3,4-ethylenedioxithiophene)intercalation for ammonium-ion supercapacitors

Recently,ammonium-ion(NH_(4)^(+))storage is in a booming stage in aqueous energy storage systems due to its multitudinous merits.To seek suitable electrode materials with excellent NH_(4)^(+)-storage is still in the exploratory stage and full of challenge.Herein,an inorganic-polymer hybrid,poly(3,4-ethylenedioxithiophene)(PEDOT)intercalated hydrated vanadium oxide(VOH),named as VOH/PEDOT,is developed to tune the structure of VOH for boosting NH_(4)^(+)storage.By the intercalation of PEDOT,the interlayer space of VOH is increased from 11.5Åto 14.2Å,which notably facilitates the rapid transport of electrons and charges between layers and improves the electrochemical properties for NH_(4)^(+)storage.The achieved performances are much better than progressive NH_(4)^(+)hosting materials.In addition,the concentration of polyvinyl alcohol/ammonium chloride(PVA/NH_(4)Cl)electrolyte exerts a great impact on the NH_(4)^(+)storage in VOH/PEDOT.The VOH/PEDOT electrode delivers specific capacitance of 327 F g^(-1)in 1 M PVA/NH_(4)Cl electrolyte at-0.2–1 V.Furthermore,the quasi-solid-state VOH/PEDOT//active carbon hybrid supercapacitor(QSS VOH/PEDOT//AC HSC)device is assembled for NH_(4)^(+)storage,and it exhibits the capacitance of 328 mF cm^(-2)at 1 mA cm^(-2).The energy density of QSS VOH/PEDOT//AC NH4 t-HSC can reach 2.9 Wh m^(-2)(2.6 mWh cm^(-3),10.4 Wh kg^(-1))at 1 Wm^(-2)(0.9 mWh cm-3,35.7 W kg^(-1)).This work not only proves that the PEDOT intercalation can boost the NH_(4)^(+)storage capacity of vanadium oxides,but also provides a novel direction for the development of NH_(4)^(+)storage materials.

PREPARATION AND CHARACTERIZATION OF POLYAMIDE 11/CLAY NANOCOMPOSITES

Polyamide 11 (PA 11) is a widely used polyamide resin, but its application is limited since the impact properties, tensile strength, and thermal properties are not very satisfactory for industrial application. In order to improve the mechanical properties of PA 11, in this paper, the preparation of polyamide 11/clay nanocomposites (PACN) via in-situ intercalated polymerization was reported. SEM, TEM and XRD were employed to investigate the dispersion of clay sheet in the matrix. The results indicate that clay layers were homogeneously dispersed in PA11 matrix on a nano-scale, and an exfoliated and intercalated structure co-existed in the composites. The mechanical and thermal properties of the obtained nanocomposites were improved to certain extent by the addition of clay.

A general synthesis strategy for the multifunctional 3D polypyrrole foam of thin 2D nanosheets

A 3D macroporous conductive polymer foam of thin 2D polypyrrole （PPy） nanosheets is developed by adopting a novel intercalation of guest （monomer Py） between the layers of the lamellar host （3D vanadium oxide foam） template-replication strategy. The 3D PPy foam of thin 2D nanosheets exhibits diverse functions including reversible compressibility, shape memory, absorption/adsorption and mechanically deformable supercapacitor characteristics. The as-prepared 3D PPy foam of thin nanosheets is highly light weight with a density of 12 mg·cm^-3 which can bear the large compressive strain up to 80% whether in wet or dry states; and can absorb organic solutions or extract dye molecules fast and efficiently. In particular, the PPy nanosheetbased foam as a mechanically deformable electrode material for supercapacitors exhibits high specific capacitance of 70 F·g^-1 at a fast charge-discharge rate of 50 mA·g^-1, superior to that of any other typical pure PPy-based capacitor. We envision that the strategy presented here should be applicable to fabrication of a wide variety of organic polymer foams and hydrogels of low-dimensional nanostructures and even inorganic foams and hydrogels of low-dimensional nanostructures, and thus allow for exploration of their advanced physical and chemical properties.