Hollow-spherical composites of Polyaniline/Cobalt Sulfide/Carbon nanodots with enhanced magnetocapacitance and electromagnetic wave absorption capabilities

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• 作者：Chuanjun Ge^a ; Xiang Zhang^a ; Jian Liu^a ; Feng Jin^a ; Jichang Liu^b ; ^{liujc@ecust.edu.cn" class="auth_mail" title="E-mail the corresponding author} ; Hong Bi^a ; ^c ; ^{bihong@ahu.edu.c" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Polyaniline ; Elelctromagnetic wave absorption ; Magnetocapacitance ; Magnetic field ; Hollow-spherical
• 刊名：Applied Surface Science
• 出版年：2016
• 出版时间：15 August 2016
• 年：2016
• 卷：378
• 期：Complete
• 页码：49-56
• 全文大小：2340 K

文摘

Hollow-spherical composites of polyaniline/cobalt sulfide/carbon nanodots (PANI/CoS/CDs-0.5T) have been synthesized by in situ polymerization under an applied magnetic field (MF) of 0.5 T. As a control, PANI/CoS/CDs-0T composites have been synthesized without a MF. Both composites acting as electrodes present obvious magnetocapacitances at a scan rate of 100 mV s⁻¹ while the electrochemical cell tested under an external MF of 0.5 T. Notably, PANI/CoS/CDs-0.5T composites show larger magnetocapacitances than PANI/CoS/CDs-0T composites at different scan rates from 5 to 100 mV s⁻¹. Electrochemical impedance spectroscopy (EIS) results indicate that MF can reduce charge transfer resistance at electrode/electrolyte interface. More importantly, PANI/CoS/CDs-0.5T composites show a much stronger electromagnetic wave (EMW) absorbing capability than PANI/CoS/CDs-0T in the range of 2–18 GHz which is attributed to an increased dielectric loss and a magnetic loss in low frequency range of 2–12.5 GHz. MF-induced ferromagnetic nanodomains of Co²⁺ clusters in the PANI/CoS/CDs-0.5T composites increase the complex permittivity and create more interfacial polarizations or the Maxwell–Wagner effect, which leads to increased dielectric loss. Compared with PANI/CoS/CDs-0T composites with diamagnetic behaviour, MF-induced weak ferromagnetism of CoS in the PANI/CoS/CDs-0.5T composites has caused additional magnetic loss. This work provides an efficient way for modulating electrochemical or electromagnetic properties of inorganic/polymer nanocomposites by employing an external MF.