title: Capacity retention behavior and morphology evolution of SixGe1-x nanoparticles as lithium-ion battery anode.
abstract: Engineering silicon into nanostructures has been a well-adopted strategy to improve the cyclic performance of silicon as a lithium-ion battery anode. Here, we show that the electrode performance can be further improved by alloying silicon with germanium. We have evaluated the electrode performance of SixGe1-x nanoparticles (NPs) with different compositions. Experimentally, SixGe1-x NPs with compositions approaching Si50Ge50 are found to have better cyclic retention than both Si-rich and Ge-rich NPs. During the charge/discharge process, NP merging and Si-Ge homogenization are observed. In addition, a distinct morphology difference is observed after 100 cycles, which is believed to be responsible for the different capacity retention behavior. The present study on SixGe1-x alloy NPs sheds light on the development of Si-based electrode materials for stable operation in lithium-ion batteries (e.g., through a comprehensive design of material structure and chemical composition). The investigation of composition-dependent morphology evolution in the delithiated Li-SiGe ternary alloy also significantly broadens our understanding of dealloying in complex systems, and it is complementary to the well-established understanding of dealloying behavior in binary systems (e.g., Au-Ag alloys).
authors.affiliation: Department of Electrical Engineering and Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, CA 90089, USA.
authors.forename: Mingyuan
authors.initials: M
authors.lastname: Ge
authors.forename: Seongbeom
authors.initials: S
authors.lastname: Kim
authors.forename: Anmin
authors.initials: A
authors.lastname: Nie
authors.forename: Reza
authors.initials: R
authors.lastname: Shahbazian-Yassar
authors.forename: Matthew
authors.initials: M
authors.lastname: Mecklenburg
authors.forename: Yunhao
authors.initials: Y
authors.lastname: Lu
authors.forename: Xin
authors.initials: X
authors.lastname: Fang
authors.forename: Chenfei
authors.initials: C
authors.lastname: Shen
authors.forename: Jiepeng
authors.initials: J
authors.lastname: Rong
authors.forename: Song
authors.initials: S
authors.lastname: Yi Park
authors.forename: Dong
authors.initials: D
authors.lastname: Suk Kim
authors.forename: Jin
authors.initials: J
authors.lastname: Young Kim
authors.forename: Chongwu
authors.initials: C
authors.lastname: Zhou