title: Probing the Additional Capacity and Reaction Mechanism of the RuO2 Anode in Lithium Rechargeable Batteries.
abstract: The structural changes and electrochemical behavior of RuO2 are investigated by using in situ XRD, X-ray absorption spectroscopy, and electrochemical techniques to understand the electrochemical reaction mechanism of this metal oxide anode material. Intermediate phase-assisted transformation of RuO2 to LiRuO2 takes place at the start of discharge. Upon further lithiation, LiRuO2 formed by intercalation decomposes to nanosized Ru metal and Li2 O by a conversion reaction. A reversible capacity in addition to its theoretical capacity is observed on discharging below 0.5 V during which no redox activity involving Ru is observed. TEM, X-ray photoelectron spectroscopy, and the galvanostatic intermittent titration technique are used to probe this additional capacity. The results show that the additional capacity is a result of Li storage in the grain boundary between nanosized Ru metal and Li2 O. Findings of this study provide a better understanding of the quantitative share of capacity by a unique combination of intercalation, conversion, and interfacial Li storage in a RuO2 anode.
authors.affiliation: Department of Energy Science, Sungkyunkwan University, Suwon 440-746 (South Korea).
authors.forename: Yunok
authors.initials: Y
authors.lastname: Kim
authors.affiliation: Department of Energy Science, Sungkyunkwan University, Suwon 440-746 (South Korea).
authors.forename: Shoaib
authors.initials: S
authors.lastname: Muhammad
authors.affiliation: Department of Energy Science, Sungkyunkwan University, Suwon 440-746 (South Korea).
authors.forename: Hyunchul
authors.initials: H
authors.lastname: Kim
authors.affiliation: Department of Chemical Engineering, Kangwon National University, Samcheok 245-711 (South Korea).
authors.forename: Yong-Hun
authors.initials: YH
authors.lastname: Cho
authors.affiliation: Department of Energy Engineering, Hanyang University, Seoul 133-791 (South Korea).
authors.forename: Hansu
authors.initials: H
authors.lastname: Kim
authors.affiliation: Department of Chemistry, Sungkyunkwan University, Suwon 440-746 (South Korea).
authors.forename: Ji Man
authors.initials: JM
authors.lastname: Kim
authors.affiliation: Department of Energy Science, Sungkyunkwan University, Suwon 440-746 (South Korea). wsyoon@skku.edu.
authors.forename: Won-Sub
authors.initials: WS
authors.lastname: Yoon
mesh_terms: D004553:Electric Conductivity; D011211:Electric Power Supplies; D004563:Electrochemistry; D004566:Electrodes; D008094:Lithium / Q000737:chemistry*; D017975:Ruthenium Compounds / Q000737:chemistry*; D013816:Thermodynamics
chemical_list: D017975:Ruthenium Compounds; C029017:ruthenium dioxide; D008094:Lithium
keywords: batteries; capacity; metal oxide anode; reaction mechanism; ruthenium