Title: Investigation on lithium storage mechanism in mixed-bond tetrahedrons of SiCO

Authors: Liqu Lin; Ningbo Liao; Miao Zhang

Addresses: School of Mechanical and Electrical Engineering, Wenzhou University, Wenzhou 325035, China ' School of Mechanical and Electrical Engineering, Wenzhou University, Wenzhou 325035, China ' School of Mechanical and Electrical Engineering, Wenzhou University, Wenzhou 325035, China

Abstract: Silicon oxycarbide (SiCO) has a capacity of ~800 mA h g⁻¹ and is considered as a promising anode material for Li-ion battery. In this work, first principle calculations were performed to study the mechanism of lithium storage for SiCO structures with different types of mixed bond tetrahedrons. The lithiated configurations show that the inserted lithium atoms are primarily bonded to oxygen and carbon atoms, and C-C bonds are present in Si-C₃O rich SiCO structures, which lead to the formation of small voids. Both formation energies and voltage curves indicate that lithium is preferable in incorporation with SiC_3/4O_5/4 than SiC_1/4O_7/4 and SiC_1/2O_3/2, which is attributed to the small voids in Si-C₃O rich structure. The results suggest that Si-centered tetrahedron provides a unique environment for lithium accommodation, and improved performance of SiCO based anodes could be achieved by optimising the type and concentration of the mixed bonds units.

Keywords: lithium-ion battery; anode material; first principle calculation; lithium storage; silicon oxycarbide; SiCO.

DOI: 10.1504/IJMSI.2017.089659

International Journal of Materials and Structural Integrity, 2017 Vol.11 No.4, pp.205 - 212

Received: 05 Oct 2017
Accepted: 05 Oct 2017
Published online: 05 Feb 2018 *

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