Mechanical properties of Li–Sn alloys for Li-ion battery anodes: A first-principles perspective

• DOI: 10.1063/1.4940131
• Publication Date: 2016-01-14T04:58:32Z
• Authors: Panpan Zhang; Zengsheng Ma; Wenjuan Jiang; Yan Wang; Yong Pan; Chunsheng Lu
• Keywords: Physics; QC1-999; 02 engineering and technology; 0210 nano-technology; 7. Clean energy; 620

Fracture and pulverization induced by large stress during charging and discharging may lead to the loss of electrical contact and capacity fading in Sn anode materials. A good understanding of mechanical properties is necessary for their optimal design under different lithiation states. On the basis of first-principles calculations, we investigate the stress-strain relationships of Li–Sn alloys under tension. The results show that the ideal tensile strengths of Li–Sn alloys vary as a function of Li concentration, and with the increase of Li+ concentration, the lowest tensile strength decreases from 4.51 GPa (Sn) to 1.27 GPa (Li7Sn2). This implies that lithiation weakens the fracture resistance of Li–Sn alloys.