Silicone, particles stabilized surface layer

Formation of the SEI layer plays an important role on the cycling stability of silicon-based anodes. Kulova and Skundin [109] reported a method used to preform the SEI layer on an electrode surface (prior to initial cathodic polarization) by direct contact of silicon and lithium metal in the electrolyte. The electrolyte was 1-M LiC104 in a mixture of propylene carbonate (PC) and dimethoxyethane. This method effectively reduced the irreversible capacity of the amorphous silicon electrode. Pretreatment of nanometer-sized silicon in ethanol also can form functionalized surfaces on the silicon particles that improve adhesion of silicon-based electrodes. A stable capacity of 2,500 mAh/g after 25 cycles has been reported for ethanol-treated silicon electrodes [110]. 

Isolated hydrophobic particles resting at one surface of a thin aqueous film can cause the film to rupture (depending on 6) when the second surface engages the particle, causing the particle to bridge the film. For this reason, small hydrophobic particles can act as antifoams or foam breakers. Commercially, antifoams are often formulations in which hydrophobic particles are dispersed in a mineral or a silicone oil. Particles adsorbed in close-packed layers on droplet interfaces in an emulsion can stabilize the emulsion even in the absence of surfactant. Indeed, in some respects monolayers of particles behave similarly to adsorbed smfactants. Thus, hydrophobic particles [which are akin to surfactants with low hydrophile-Upophile balance (HLB)] can stabilize water-in-oil emulsions, whereas hydrophilic particles can be expected to stabilize oil-in-water emulsions (just as high-HLB surfactants do). In the first part of the chapter aspects of the current state of imderstanding of the effects that adsorbed particles have on foam and emulsion stabihty are reviewed. 

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