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Qi K.,Huazhong University of Science and Technology | Qiu Y.,Huazhong University of Science and Technology | Guo X.,Huazhong University of Science and Technology | Guo X.,Key Laboratory for Large Format Battery Materials and System
Electrochimica Acta | Year: 2014

In order to synthesize a PPy/GO composite for supercapacitor applications, a pulse electro-polymerization method was proposed to direct incorporate graphene oxide (GO) into polypyrrole (PPy) films without any additional dopants. The PPy/GO prepared by the pulse electro-polymerization (PC PPy/GO) exhibits a higher specific capacitance. A shorter pulse on time (ton) results in higher specific capacitance, but there is an optimum pulse current amplitude (IA) related to the highest specific capacitance. The PC PPy/GO film (IA = 4 mA cm-2, ton = 50 ms) has a high specific capacitance of 660 F g-1 estimated from galvanostatic charge-discharge in 1 M KCl at a current density of 0.5 mA cm-2. Stability tests for the PPy/GO yield long cycling life up to 1000 cycles with 10% decay in specific capacitance at charge-discharge current density of 10 mA cm-2 in the potential range of -0.5 to 0.5 VSCE. © 2014 Elsevier Ltd.


Zhang Y.,Key Laboratory for Large Format Battery Materials and System | Zhang Y.,Huazhong University of Science and Technology | Liu W.,Huazhong University of Science and Technology | Banks C.E.,Manchester Metropolitan University | And 4 more authors.
Scientific Reports | Year: 2014

As a typical biomineral, hydroxyapatite (HAp) is widely applied in bone implants and other related fields. However, the inherent nature of HAp can potentially be altered through restricting its fabrication conditions. Here, HAp fabricated by a hydrothermal treatment of pieces of natural seashell is demonstrated to have the capability of fluorescence quenching. To the best of the author's knowledge, this is the first time that this new property of HAp has been reported. Consequently, we assembled a fluorescence-quenching platform based on the biomineralized HAp substrate following a hydrothermal treatment and associated with a DNA molecular beacon and applied to cancer cell detection by the transformation from "OFF state" (fluorescence quenching) to "ON state" (fluorescence recovery). Herein, we found that the outer surface of HAp material after hydrothermal biomineralization for 5 days has considerable capability for both fluorescence quenching and recovery. These results may also have implications in the further detection of various targets such as cancer cells with other special surface antigens, significant biological small molecules or disease related microRNA, just by changing the sequence of the nucleic acid beacon according to the corresponding aptamer.


Qi K.,Huazhong University of Science and Technology | Qi K.,Xi'an Jiaotong University | Qiu Y.,Huazhong University of Science and Technology | Chen Z.,Huazhong University of Science and Technology | And 3 more authors.
Corrosion Science | Year: 2015

In deaerated or aerated 0.1. M NaCl (pH = 1 or 7), galvanic interactions between polypyrrole (PPy) films and different metals (13Cr, NiTi, Pt, Ti and Cu) were investigated in simulated galvanic couples. The PPy suffers cathodic polarisation while the substrate metals (apart from Pt) suffer anodic polarisation. When the substrate metal is inert or well passivated, such as Pt or Ti, there is no galvanic interaction between them. When the substrate metal is in a poor passivation or an active dissolution state, such as 13Cr, NiTi or Cu, the galvanic interactions between them may be strong and cannot be ignored. © 2014 Elsevier Ltd.


Chen W.-M.,Key Laboratory for Large Format Battery Materials and System | Qie L.,Key Laboratory for Large Format Battery Materials and System | Shen Y.,Key Laboratory for Large Format Battery Materials and System | Sun Y.-M.,Key Laboratory for Large Format Battery Materials and System | And 4 more authors.
Nano Energy | Year: 2013

Carbon-encapsulated nano-MnO composite with novel multiple structure loaded on N-doped carbon webs (CMNCWs) has been designed and fabricated by using polypyrrole webs as both template and precursor. As an anode material for lithium-ion batteries, CMNCWs exhibit a superhigh reversible capacity and excellent rate capability, delivering a capacity as high as 1268mAhg-1 after 700 cycles at a current density of 1.0Ag-1. Such superior electrochemical performance can be attributed to the unique multiple structure, which cannot only effectively shorten the transport path of Li+ ions and enhance the conductivity, but also relieve the volume change and prevent agglomeration of Mn grains during the phase transformation in the conversion reaction. © 2012 Elsevier Ltd.


Yang H.,Huazhong University of Science and Technology | Yang H.,Key Laboratory for Large Format Battery Materials and System | Qiu Y.,Huazhong University of Science and Technology | Guo X.,Huazhong University of Science and Technology | Guo X.,Key Laboratory for Large Format Battery Materials and System
Electrochimica Acta | Year: 2016

In order to improve the high-rate partial-state-of-charge (HRPSoC) performance of lead-acid batteries for hybrid-electric vehicles, graphene oxide (GO), polypyrrole (PPy) and three PPy/GO composites with different weight ratio of pyrrole to GO (mpy/mGO) were selected as additives to form negative plates and simulated test cells. The effects of these additives on the electrochemical performance and the microstructure of the negative plate and on the HRPSoC cycle performance of the simulated test cell were investigated. The results indicate that the microstructure of the negative plate is changed with the addition of different additives. GO significantly increases the hydrogen (H2) evolution ability of the negative plate, while PPy has the opposite effect. The incorporation of the proper content of PPy with GO can effectively inhibit the H2 evolution of the negative plate. Moreover, adding different additives in the negative plate also decreases its total impedance, accelerates the redox processes between Pb and PbSO4 on it and increases its specific capacitance. GO and the PPy/GO composite with mpy/mGO = 1:1 (PG1) can significantly increase the HRPSoC cycle life of the simulated test cell. Considering the H2 evolution performance and the HRPSoC cycle performance, the PPy/GO composites with a medium mpy/mGO ratio, such as PG1, may be the appropriate additives for the negative plate of lead-acid batteries. © 2016 Elsevier Ltd


Li P.,Key Laboratory for Large Format Battery Materials and System | Li P.,Huazhong University of Science and Technology | Wang H.,State Key Laboratory of Organic Solids | Wang H.,CAS Beijing National Laboratory for Molecular | And 17 more authors.
Science China Chemistry | Year: 2016

Balanced carrier transport is observed in acceptor-acceptor (A-A′) type polymer for ambipolar organic thin-film transistors (OTFTs). It is found that the incorporation of two electron-accepting moieties (BTz and IIG) into a polymer main chain to form A-A′ polymer PIIG-BTz could lower highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) levels and facilitate good molecular stacking of the polymer. Ambipolar transistor behaviour for PIIG-BTz, with the balanced hole and electron mobilities of 0.030 and 0.022 cm2 V−1 s−1 was observed in OTFT devices, respectively. The study in this work reveals that the utilization of acceptor-acceptor (A-A′) structure in polymer main chain can be a feasible strategy to develop ambipolar polymer semiconductors. © 2016, Science China Press and Springer-Verlag Berlin Heidelberg.

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