Microwave-Assisted Synthesis of NaCoPO4 Red-Phase and Initial Characterization as High Voltage Cathode for Sodium-Ion Batteries

Arturo Gutierrez; Soojeong Kim; Timothy T Fister; Christopher S Johnson

doi:10.1021/acsami.6b14341

Microwave-Assisted Synthesis of NaCoPO₄ Red-Phase and Initial Characterization as High Voltage Cathode for Sodium-Ion Batteries

ACS Appl Mater Interfaces. 2017 Feb 8;9(5):4391-4396. doi: 10.1021/acsami.6b14341. Epub 2017 Jan 20.

Authors

Arturo Gutierrez¹, Soojeong Kim¹, Timothy T Fister¹, Christopher S Johnson¹

Affiliation

¹ Chemical Sciences and Engineering Division, Argonne National Laboratory , 9700 South Cass Avenue, Argonne, Illinois 60439, United States.

PMID: 28106986
DOI: 10.1021/acsami.6b14341

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 M^n+/(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 Co^2+/3+ redox center.

Keywords: NaCoPO4; XANES; microwave synthesis; polyanion; polymorph; sodium batteries.