MgCo 2 O 4 is a promising electrode material in electrochemical energy storage devices. In this work, the supercritical CO 2 -assisted solvothermal (SCAS) method was applied to synthesize MgCo 2 O 4 nanomaterials for the first time. The crystallite size of the MgCo 2 O 4 prepared by SCAS was significantly smaller than the one prepared by the ethanol solvothermal method, reaching 9.0 nm at a CO 2 pressure of 16 MPa. The as-prepared MgCo 2 O 4 nanospheres exhibited a special spherical structure with abundant irregular pores and a high specific surface area of 69.9 m 2 /g. X-ray photoelectron spectroscopy demonstrated that the Co 3+ /Co 2+ ratio of the MgCo 2 O 4 was increased by the SCAS method and the mechanism of synthesizing MgCo 2 O 4 nanospheres was explored. In addition, the MgCo 2 O 4 electrode material prepared by the SCAS method exhibited a high specific capacitance of 741 F/g at 0.1 A/g. The results confirm that the SCAS method can synthesize ultrafine MgCo 2 O 4 nanoparticles with special morphology and high specific surface area, which are expected to be applied in high-performance electrode materials.
Jin-Ju Chen,Qi An,Raul D. Rodriguez,Evgeniya Sheremet,Yan Wang,Enrico Sowade,Reinhard R. Baumann,Zhe-Sheng Feng
Metallized polyimide (PI) film has great applications in the field of flexible electronics. Surface property adjustment is considered as an effective way to realize the metallization of PI film by chemical methods . In this work, we demonstrate a facile approach to fabricate metallized PI film via surface modification and electroless plating . Polyethyleneimine (PEI) cross-linked with glutaraldehyde (GA) is used as a modifier to act on the surface of alkali-treated PI film, and a special regular morphology is obtained. This PEI-modified PI film possesses not only functional groups for chemical bonding but also large surface roughness for mechanical locking with metallic copper layer. The resulting copper layer has low resistivity (2.30 μΩ·cm) and satisfactory adhesion to PI film (the highest score of 5B according to ASTM D3359), and the metallized PI sample exhibits reliable flexibility. These results demonstrate a promising potential of this approach in the field of PI film metallization with impact in wearables, light-weight, and flexible electronics.
Chan Wang,Miao Yang,Wenna Zhang,Xiong Su,Shutao Xu,Peng Tian,Zhongmin Liu
With the aid of self-designed organophosphorous surfactant [2-(diethoxylphosphono)propyl]hexadecyldimethylammonium bromide (DPHAB), SAPO-34s with various special morphologies have been hydrothermally synthesized by using tetraethylammonium hydroxide (TEAOH), diethylamine (DEA) and triethylamine (TEA) as templates, respectively. The synthesized SAPO-34s were well characterized by XRD, XRF, SEM, N2 adsorption–desorption, solid state NMR and NH3-TPD measurements. The status of DPHAB was also investigated by using FT-IR, 13C NMR, TG–DTA and 31P NMR measurements as well as density functional theory calculations. It is found that the addition of DPHAB changes the crystal morphology dramatically and the aggregation degree of the crystals increases with the rising DPHAB/H3PO4 ratio. Moreover, microporous templates play an important role in the synthesis of mesoporous SAPO-34. TEAOH, which has the strongest interaction energy with the CHA framework among the investigated templates, shows the best cooperating ability with an organophosphorous surfactant to direct the formation of nanosized and mesoporous SAPO-34. The prepared SAPO-34s showed improved catalytic properties in the methanol-to-olefins (MTO) reaction.
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