Siloxane-Based Organosilicon Materials in Electrochemical Energy Storage Devices.

Siloxane-based molecular material, by virtue of its unique chemical structure, thermal and electrochemical properties, has triggered tremendous research interest and sparked a revolution for energy storage in the past years. Siloxanes and their analogues are generally demonstrated to be more environmentally friendly, durable, and safer when employed to reconstruct the nano-micro surface structure of electrodes, separators, and their interfaces with electrolytes. To better understand the recent and comprehensive achievement of siloxane-based materials in energy storage, a systematic summary is necessary to provide important clues, aiming at achieving better electrochemical properties. In this Minireview, siloxane materials are presented comprehensively and systematically in terms of molecule design, functionality, and unique superiority for lithium-ion batteries and supercapacitors. The challenges, perspectives, and future directions of siloxane-based organosilicon materials are put forward for higher performance and wider application in electrochemical energy storage devices.

Build a Rigid-Flexible Graphene/Silicone Interface by Embedding SiO2 for Adhesive Application.

An effective strategy was developed to enhance the adaptability of graphene/silicone matrices under external stimuli by embedding nanoscale SiO2 into the graphene/silicone interfaces as a buffer layer. Chemically reduced graphene (rGE) was first covered by SiO2 using an in situ preparation, forming sandwichlike rGE/SiO2 (rGES). Then, rGES was integrated into methyl vinyl polysiloxane, followed by vulcanization, producing the final rGES/silicone rubber (SR) nanocomposite. Such interfacial modification actually built a rigid-flexible SiO2 buffer layer between rGE and polysiloxane. Obvious improvements were seen in both thermal and mechanical properties due to improved interfacial interaction. In a vulcanized rGES/SR system, the addition of 30 wt % rGES (3 wt % rGE) yielded a tensile strength of 6.13 MPa (up to 25 times that of the unmodified rGE in filled SR), a tear strength of 18.08 kN/m, and an elongation at break of 267%, several times higher than those of an rGE/SR nanocomposite. Thermal analysis results indicated that the initial decomposition temperature of rGES/SR containing 5 wt % rGES (0.5 wt % rGE) increased by more than 98 and 288 °C compared to that of SiO2/SR and rGE/SR, respectively. The rGES/polysiloxane matrices showed a tensile shear adhesive strength of 1.78 MPa when used as an adhesive for aluminum sheets, which is higher than that of the rGE/polysiloxane matrix (0.93 MPa).

Effect of graphene oxide on the properties of its composite with polyaniline.

Graphene oxide, a single layer of graphite oxide (GO), has been used to prepare graphene oxide/polyaniline (PANI) composite with improved electrochemical performance as supercapacitor electrode by in situ polymerization using a mild oxidant. The composites are synthesized under different mass ratios, using graphite as start material with two sizes: 12 500 and 500 mesh. The result shows that the morphology of the prepared composites is influenced dramatically by the different mass ratios. The composites are proposed to be combined through electrostatic interaction (doping process), hydrogen bonding, and pi-pi stacking interaction. The highest initial specific capacitances of 746 F g(-1) (12 500 mesh) and 627 F g(-1) (500 mesh) corresponding to the mass ratios 1:200 and 1:50 (graphene oxide/aniline) are obtained, compared to PANI of 216 F g(-1) at 200 mA g(-1) by charge-discharge analysis between 0.0 and 0.4 V. The improved capacitance retention of 73% (12 500 mesh) and 64% (500 mesh) after 500 cycles is obtained for the mass ratios 1:23 and 1:19 compared to PANI of 20%. The enhanced specific capacitance and cycling life implies a synergistic effect between two components. This study is of significance for developing new doped PANI materials for supercapacitors.

A nanostructured graphene/polyaniline hybrid material for supercapacitors.

A flexible graphene/polyaniline hybrid material as a supercapacitor electrode was synthesized by an in situ polymerization-reduction/dedoping-redoping process. This product was first prepared in an ethylene glycol medium, then treated with hot sodium hydroxide solution to obtain the reduced graphene oxide/polyaniline hybrid material. Sodium hydroxide also acted as a dedoping reagent for polyaniline in the composite. After redoping in an acidic solution, the thin, uniform and flexible conducting graphene/polyaniline product was obtained with unchanged morphology. The chemical structure of the materials was characterized by X-ray photoelectron spectroscopy and Raman spectroscopy. The composite material showed better electrochemical performances than the pure individual components. A high specific capacitance of 1126 F g(-1) was obtained with a retention life of 84% after 1000 cycles for supercapacitors. The energy density and power density were also better than those of pure component materials.

[Multi-central randomized controlled investigation on the massage for supplementing qi and removing obstruction in the Governor Vessel for treatment of infantile diarrhea due to spleen deficiency].

OBJECTIVE: To make multi-central clinical evaluation of the massage for supplementing qi and removing obstruction in the Governor Vessel for treatment of infantile diarrhea due to spleen deficiency. METHODS: By using multi-central, randomized and controlled method, 275 cases were randomly divided into an observation group (n = 137) and a control group (n = 138). The observation group were treated by the massage for supplementing qi and removing obstruction in the Governor Vessel, and the control group by routine massage therapy in Tuina Science, a teaching material for college and school of TCM. After treatment for 7 days, their therapeutic effects were compared. RESULTS: The cured rate was 83.2% in the observation group and 69.6% in the control group with a signifi cant difference between the two groups (P < 0.05), the former being better than the latter. The mean cured time was (3.22 +/- 1.04) days in the observation group and (4.20 +/- 1.11) days in the control group with a significant difference between the two groups (P < 0.05), the former being shorter than the latter. CONCLUSION: The massage for supplementing qi and removing obstruction in the Governor Vessel has a definite therapeutic effect on infantile diarrhea due to spleen deficiency, with rapid effect.