In Situ X-ray Absorption Spectroscopy Study of the Capacity Fading Mechanism in Hybrid Sn 3 O 2 (OH) 2 /Graphite Battery Anode Nanomaterials
In situ x-ray absorption spectroscopy (XAS) of an electrode material under electrochemical control has enabled a detailed examination of the aging mechanism in a hybrid nanomaterial, Sn3O2(OH)2/graphite, that is considered for use as a high capacity lithium-ion battery anode. By the use of an original one-pot solvothermal synthesis technique, Sn3O2(OH)2 nanoparticles were directly deposited on the surface of nano-thin graphite and were charged/discharged in situ for several cycles while XAS spectra at the Sn K-edge were taken. Modeling of collected extended x-ray absorption fine structure (EXAFS) spectra provides detailed information on the Sn-O, Sn-Sn and Sn-Li coordination numbers and atomic distances for each charged and discharged electrode state. Based on the changes in atomic arrangement deduced from the EXAFS fitting results, including the first unambiguous observation of Sn-Li near neighbors, an aging mechanism is proposed in which metallic tin clusters are created surrounded by a highly disordered Li2O shell that is formed on first charge. The metallic tin cluster participates in lithiation and delithiation on the following charge/discharge cycles, however the clusters slowly lose electrical contact with the rest of the electrode and become excluded from further participation in electrochemical reactions, resulting in the reduced capacity of this anode material.
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES)
- DOE Contract Number:
- AC02-06CH11357
- OSTI ID:
- 1395992
- Journal Information:
- Chemistry of Materials, Vol. 27, Issue 2; ISSN 0897-4756
- Publisher:
- American Chemical Society (ACS)
- Country of Publication:
- United States
- Language:
- English
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