title: Ternary metal fluorides as high-energy cathodes with low cycling hysteresis.
abstract: Transition metal fluorides are an appealing alternative to conventional intercalation compounds for use as cathodes in next-generation lithium batteries due to their extremely high capacity (3-4 times greater than the current state-of-the-art). However, issues related to reversibility, energy efficiency and kinetics prevent their practical application. Here we report on the synthesis, structural and electrochemical properties of ternary metal fluorides (M(1)yM(2)(1-y)F(x): M(1), M(2) = Fe, Cu), which may overcome these issues. By substituting Cu into the Fe lattice, forming the solid-solution Cu(y)Fe(1-y)F(2), reversible Cu and Fe redox reactions are achieved with surprisingly small hysteresis (<150 mV). This finding indicates that cation substitution may provide a new avenue for tailoring key electrochemical properties of conversion electrodes. Although the reversible capacity of Cu conversion fades rapidly, likely due to Cu(+) dissolution, the low hysteresis and high energy suggest that a Cu-based fluoride cathode remains an intriguing candidate for rechargeable lithium batteries.
authors: Sustainable Energy Technologies Department, Brookhaven National Laboratory, Upton, New York 11973, USA.
authors: Feng
authors: F
authors: Wang
authors: Sustainable Energy Technologies Department, Brookhaven National Laboratory, Upton, New York 11973, USA.
authors: Sung-Wook
authors: SW
authors: Kim
authors: 1] Department of Materials Science and Engineering, Research Institute of Advanced Materials, Seoul National University, Seoul 151-742, Republic of Korea [2] Center for Nanoparticle Research, Institute for Basic Science, Seoul National University, Seoul 151-742, Republic of Korea.
authors: Dong-Hwa
authors: DH
authors: Seo
authors: 1] Department of Materials Science and Engineering, Research Institute of Advanced Materials, Seoul National University, Seoul 151-742, Republic of Korea [2] Center for Nanoparticle Research, Institute for Basic Science, Seoul National University, Seoul 151-742, Republic of Korea.
authors: Kisuk
authors: K
authors: Kang
authors: Sustainable Energy Technologies Department, Brookhaven National Laboratory, Upton, New York 11973, USA.
authors: Liping
authors: L
authors: Wang
authors: Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, USA.
authors: Dong
authors: 0000000219216683
authors: D
authors: Su
authors: Sensors and Materials Laboratory, HRL Laboratories, LLC, Malibu, California 90265, USA.
authors: John J
authors: JJ
authors: Vajo
authors: Sensors and Materials Laboratory, HRL Laboratories, LLC, Malibu, California 90265, USA.
authors: John
authors: J
authors: Wang
authors: 1] Sustainable Energy Technologies Department, Brookhaven National Laboratory, Upton, New York 11973, USA [2] Sensors and Materials Laboratory, HRL Laboratories, LLC, Malibu, California 90265, USA.
authors: Jason
authors: J
authors: Graetz