Preparation Of Silicon-based Alloy Anode Material Andelectrochemical Properties

With the rapid development of the modern society, the mobile communications and other electronic equipment for lithium ion batteries have the higher capacity requirements. Silicon alloy anode material is paid more attention by the researchers because of its high capacity. In this article, binary alloy and ternary alloy are made by ball milling in acetone after pure metal had been melting, and studied the modification of alloy material mixed with carbon. Electrochemical performance of silicon alloy as Lithium battery anode material was tested, the charge-discharge mechanism of silicon alloy was researched, the reason why electrochemical performance improves after modification of alloy material mixed with carbon was also investigated in this article. The main conclusions are as below:(1) The first discharge capacity of binary alloy and ternary alloy is both higher , but the first charge capacity is smaller. For example, the first charge-discharge capacities of the sample with Si content 80% are 332 mAh/g, 1409mAh/g respectivitily in the Fe-Ni-Si alloy. Overmore, cycling performance of the alloy is poorer. The capacity of the sample with Si content 80% in the Fe-Ni-Si alloy will be 0 after 5 cycles.(2) After the modification, the first charge capacity and cycling performance of binary alloy and ternary alloy are greatly improved. For example, the first charge-discharge capacities of the sample with Si content 80% are 520 mAh/g, 950mAh/g in the Fe-Ni-Si alloy. The capacity remains 180 mAh/g till it cycles to the tenth week. But the Si content is lower in the sample with the better electrochemical performance.(3) Binary alloy,ternary alloy and the alloy after modification have the same charge and discharge mechanism. The main components of the alloy and the material after modification are simple substance Si and Inert alloy. Simple substance Si reacts with Li+ in the process of charge-discharge, and plays a role in providing capacity. Inert alloy Plays a supporting frame structure of the material, and eases the effect that Si reacts with Li+ in the process of charge-discharge.(4)In binary alloys, Ni-Si modified before the electrochemical properties of binary alloys is superior to Fe-Si binary alloy. The doped carbon modification, the electrochemical properties of binary alloys is greatly is greatly improved, Fe-Si/C composite material is superior electrochemical performance Ni-Si/C composite materials. Comparison of binary alloys and ternary alloys, ternary alloys modified to be better than before and after theelectrochemical properties of binary alloys.