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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]