title: Microwave-Assisted Synthesis of NaCoPO4Red-Phase and Initial Characterization as High Voltage Cathode for Sodium-Ion Batteries.
abstract: Transition metal-containing polyanion compounds are attractive for use as cathode materials in sodium-ion batteries (SIB) because they possess elevated higher intrinsic electrochemical potentials versus oxide analogs given the same Mn+/(n+1)+redox couple, which leads to higher energy densities. NaMPO4(M = transition metal) compounds have a driving force to form into the electrochemically inactive maricite phase when using conventional methods. Herein we report on the synthesis of a NaCoPO4(NCP) polymorph ("Red"-phase) by a microwave-assisted solvothermal process at 200 °C using tetraethylene glycol as the solvent. Ex situ XRD, XANES, and electrochemical data are used to determine the reversibility of the Co2+/3+redox center.
authors.affiliation: Chemical Sciences and Engineering Division, Argonne National Laboratory , 9700 South Cass Avenue, Argonne, Illinois 60439, United States.
authors.forename: Arturo
authors.identifier: http://orcid.org/0000-0002-2899-3089
authors.initials: A
authors.lastname: Gutierrez
authors.affiliation: Chemical Sciences and Engineering Division, Argonne National Laboratory , 9700 South Cass Avenue, Argonne, Illinois 60439, United States.
authors.forename: Soojeong
authors.initials: S
authors.lastname: Kim
authors.affiliation: Chemical Sciences and Engineering Division, Argonne National Laboratory , 9700 South Cass Avenue, Argonne, Illinois 60439, United States.
authors.forename: Timothy T
authors.initials: TT
authors.lastname: Fister
authors.affiliation: Chemical Sciences and Engineering Division, Argonne National Laboratory , 9700 South Cass Avenue, Argonne, Illinois 60439, United States.
authors.forename: Christopher S
authors.identifier: http://orcid.org/0000-0003-4357-6889
authors.initials: CS
authors.lastname: Johnson
keywords: NaCoPO4; XANES; microwave synthesis; polyanion; polymorph; sodium batteries