Determination of optimal composition of Al-Si precursor alloys in dealloying process on melt fragility

摘要

Nanoporous metal materials synthesized by dealloying play a vital role in catalysis, energy sources, sensors and biological monitoring fields. The alloy composition can greatly affect the structure and porosity of dealloyed products. But in many cases, the composition of precursor alloy is optimized by a trial-and-error approach. To determine the optimal composition of Al-Si precursor alloys, we investigated their melt fragility. It is found that Al-Si eutectic alloy possesses not merely the smallest melt fragility, but also the strongest tendency to form honeycomb-like nanoporous Si with large specific surface area. A prediction of the optimal composition of Al-Si precursor alloys is realized by melt fragility. When used as lithium-ion batteries anodes, the honeycomb-like nanoporous Si_(12) anode delivers a better cycling performance with a higher capacity retention than that of Si_7 and Si_(20) anodes. This strategy allows for prediction of the optimal precursor alloy composition in dealloying.