title: Highly Reversible and Superior Li-Storage Characteristics of Layered GeS2and Its Amorphous Composites.
abstract: A layered GeS2material was assessed as an electrode material in the fabrication of superior rechargeable Li-ion batteries. The electrochemical Li insertion/extraction behavior of the GeS2electrode was investigated from extended X-ray absorption measurements as well as by cyclic voltammetry and differential capacity plots to better understand its Li insertion/extraction behavior. Using the Li insertion/extraction reaction mechanism of the GeS2electrode, an interesting amorphous GeS2-based composite was developed and tested for use as a high-performance electrode. Interestingly, the amorphous GeS2-based composite electrode exhibited highly reversible discharging and charging reactions, which were attributed to a conversion/recombination reaction. The amorphous GeS2-based composite electrode exhibited highly reversible and outstanding electrochemical performances, a highly reversible capacity (first charge capacity: 1298 mAh g-1) with a high first Coulombic efficiency (83.3%), rapid rate capability (ca. 800 mAh g-1at a high current rate of 700 mA g-1), and long capacity retention over 180 cycles with high capacity (1100 mAh g-1) thanks to its interesting electrochemical reaction mechanism. Overall, this layered GeS2and its amorphous GeS2/C composite are novel alternative anode materials for the potential mass production of rechargeable Li-ion batteries with excellent performance.
authors.affiliation: School of Materials Science and Engineering, Kumoh National Institute of Technology , 61 Daehak-ro, Gumi, Gyeongbuk 39177, Republic of Korea.
authors.forename: Geon-Kyu
authors.initials: GK
authors.lastname: Sung
authors.affiliation: Department of Environmental Engineering, Inha University , 100 Inha-ro, Nam-gu, Incheon 22212, Republic of Korea.
authors.forename: Ki-Joon
authors.initials: KJ
authors.lastname: Jeon
authors.affiliation: School of Materials Science and Engineering, Kumoh National Institute of Technology , 61 Daehak-ro, Gumi, Gyeongbuk 39177, Republic of Korea.
authors.forename: Cheol-Min
authors.initials: CM
authors.lastname: Park
keywords: amorphous composite; anode materials; germanium sulfide; lithium batteries; reaction mechanism