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Lithium-ion batteries (LIB) with both high volumetric and gravimetric specific capacities are desirable for power sources in microsystems. Si is a promising anode material for the above LIBs. However, its huge volume change combined with strict constraint by the bulky current collector (and/or the substrate) during lithiation/delithiation causes a severe stress and thus rapid capacity fading. Strategies in the literatures help suppress the capacity fading but degrade the anode initial Coulombic efficiency and specific capacities. This work presents a freestanding Si anode with an ultrathin current collector. Unlike those in the literatures whose current collector (and/or the substrate) accounts for the main part, the Si film dominates in this freestanding anode. This causes weak constraint from the current collector, therefore, the Si film can expand/shrink easily and stress induced by Si volume change can be effectively released, thus resulting in good anode cyclability (98.6% retention over 150 cycles). Moreover, the dominant role of the Si film in this anode ensures the anode to have high volumetric (6989 mAh cm-3) and gravimetric (2107 mAh g-1) specific capacities even when both the Si and current collector are included for calculations. This freestanding anode also displays a high initial Coulombic efficiency of 92.8% due to its small surface area. [ABSTRACT FROM AUTHOR]

Silver nanoparticles (AgNPs) are synthesized in a plasma electrochemical system with an aqueous solution of AgNO3 as anode. 5-Bromouracil, ethanol and dimethyl sulfoxide are added to the solutions for tuning the plasma-induced liquid chemistry. The characteristic localized surface plasmon resonance of the AgNPs is used to investigate the AgNPs formation process. The results indicate that there exists Ag+ reduction and Ag oxidation simultaneously during the AgNPs formation, and the hydrated electrons formed by the dissolution of plasma electrons are the main reducing agents for the Ag+ reduction, while the hydrogen peroxide produced by the plasma-liquid interactions plays a role in etching the formed AgNPs to Ag+. [ABSTRACT FROM AUTHOR]

Discharge plasma–liquid systems provide an interesting research field for many physical and chemical processes. These fascinating processes can be studied by using systems with liquid as anode and cathode, and the yield of aqueous hydrogen peroxide (H2O2aq) in the plasma–liquid system with the liquid anode is significantly lower than that with the liquid cathode. We improve the H2O2aq yield in the plasma–liquid system with the liquid anode by adding appropriate amount of ethanol in the liquid. A seven-time increase in the production rate is reached when the ethanol volume concentration is 5%, while further increase in the ethanol concentration will decrease the production rate. The H2O2aq production improvement is ascribed to the atomic oxygen-induced hydrogen abstraction reactions from ethanol which in situ improve the concentration of the H2O2 building brick, the OH radicals, in the liquid. However, excessive ethanol can scavenge the in situ formed OH radicals through the hydrogen abstraction reaction, by which the H2O2aq formation is inhibited. [ABSTRACT FROM AUTHOR]

Using an aqueous solution of NaCl as the cathode, we explored the atmospheric pressure Ar discharge plasma generated above the solution surface. The formation pathways of aqueous hydrogen peroxide (H2O2aq) in this system were investigated. Dimethyl sulfoxide was used as a scavenger of hydroxyl (OH) radicals to investigate the contribution of dissolved OH radicals to the H2O2aq. The results indicate that the H2O2aq is mainly formed by the combination of the dissolved OH radicals at the plasma-affected thin liquid layer, while the H2O2 formed in the gas phase and the H2O2aq formation inside water by the plasma-induced ultraviolet radiation have no contribution. [ABSTRACT FROM AUTHOR]