Identifying Hidden Li–Si–O Phases for Lithium-Ion Batteries via First-Principle Thermodynamic Calculations

Energy & Environmental Materials

article

Jiale Qu¹  Chao Ning¹  Dr. Xiang Feng¹  Bonan Yao¹  Bo Liu²  Ziheng Lu³  Tianshuai Wang¹  Zhi Wei Seh⁴  Siqi Shi⁵  Qianfan Zhang¹ 

[1] School of Materials Science and Engineering, Beihang University;College of Mathematics and Physics, Jinggangshan University;Department of Materials Science & Metallurgy, University of Cambridge;Institute of Materials Research and Engineering, Agency for Science, Technology and Research;School of Materials Science and Engineering, Shanghai University

关键词: anode material;    crystal structure prediction;    first-principle calculations;    ternary alloy phase;   

DOI  :  10.1002/eem2.12329

来源: Wiley

【 摘 要 】

SiO–based materials are promising alloys and conversion-type anode materials for lithium-ion batteries and are recently found to be excellent dendrite-proof layers for lithium-metal batteries. However, only a small fraction of the Li–Si–O compositional space has been reported, significantly impeding the understanding of the phase transition mechanisms and the rational design of these materials both as anodes and as protection layers for lithium-metal anodes. Herein, we identify three new thermodynamically stable phases within the Li–Si–O ternary system (Li 2 SiO 5 , Li 4 SiO 6, and Li 4 SiO 8 ) in addition to the existing records via first-principle calculations. The electronic structure simulation shows that Li 2 SiO 5 and Li 4 SiO 8 phases are metallic in nature, ensuring high electronic conductivity required as electrodes. Moduli calculations demonstrate that the mechanical strength of Li–Si–O phases is much higher than that of lithium metal. The diffusion barriers of interstitial Li range from 0.1 to 0.6 eV and the interstitial Li hopping serves as the dominating diffusion mechanism in the Li–Si–O ternary systems compared with vacancy diffusion. These findings provide a new strategy for future discovery of improved alloying anodes for lithium-ion batteries and offer important insight towards the understanding of the phase transformation mechanism of alloy-type protection layers on lithium-metal anodes.

【 授权许可】

Unknown