Rapid mechanochemical synthesis of amorphous alloys

Abstract

A rapid method for preparing amorphous alloys has been developed utilizing a SPEX high energy ball mill. Parameters such as ball size, mass of balls and milling time, were systematically optimized to prepare amorphous alloys quickly. Amorphous alloys previously not thought possible to synthesize by means of SPEX milling were made amorphous by the new method. When applied to the preparation of Sn-Co-C and Si-Fe alloys, the method was found to produce fully amorphous alloys in a matter of hours instead of days or weeks of milling by traditional techniques. Electrochemical performance of the alloys produced by the rapid milling technique in Li cells was found to be the same or superior to alloys produced by the more time consuming methods, confirming their amorphous microstructure.

A Simple Synthesis Route for High-Capacity SiOx Anode Materials with Tunable Oxygen Content for Lithium-Ion Batteries

“…Also, TEM images of SO0 are shown in Figure S2. This sample consists of ∼5–10 nm silicon crystallites in an amorphous silicon matrix, which is typical of ball milled Si. − As the air exposure time during milling is increased, the amount of silicon oxide phase increases linearly. With increased oxygen content, the n-Si content reduces substantially.…”

Si(CO)y Negative Electrodes for Li-Ion Batteries

“…As the CO 2 exposure time increases, the integrated intensity of the Si­(CO) y phase increases in roughly the same manner as the C and O contents, as shown in Figure a, while the amount of crystalline and amorphous Si decreases accordingly. The crystalline Si peak is broad for the CO 2 0h sample, indicating the formation of nanocrystalline Si, which is typically formed when Si is ball-milled . However, the crystalline Si peak is narrower and its width is the same for all of the CO 2 -milled samples.…”

“…The pattern was fit using pseudo-Voigt peak shape functions and a polynomial background. The XRD pattern of the CO 2 0h sample comprises amorphous and nanocrystalline Si components, which is typical of ball-milled Si . For samples milled in CO 2 , the crystalline Si peaks decrease in intensity, while broad peaks corresponding to amorphous silicon increase with intensity with increasing CO 2 exposure time.…”

“…The crystalline Si peak is broad for the CO 2 0h sample, indicating the formation of nanocrystalline Si, which is typically formed when Si is ball-milled. 39 However, the crystalline Si peak is narrower and its width is the same for all of the CO 2 -milled samples. We speculate that when Si is fractured during ball milling, CO 2 reacts with freshly exposed Si surfaces rapidly, forming amorphous Si(CO) y phases surrounding crystalline silicon (as shown by TEM in Figure 1).…”

In Situ Analytical Methods for the Characterization of Mechanochemical Reactions

“…Particular attention has been paid to the synthesis of metal alloys, oxides, pharmaceuticals, co-crystals, and large porous framework structures such as MOFs or ZIFSs, to name but a few. Some examples, out of many others for the application of mechanochemistry, are material synthesis [17][18][19], structural phase transformations [20][21][22][23], amorphization [24,25], oxidation and reduction reactions, hydrogenation or nitridation [26,27], alloying [28][29][30], intercalation [31,32], and catalytic reactions [33][34][35].…”