Synthesis and Stoichiometry of Different Layered Sodium Cobalt Oxides

Layered Na–metal oxides can form in different crystal structures, each with different electrochemical behavior. As a prototype system to better understand how each phase can be formed, we present the conditions under which different layered phases of NaxCoO2 can be stabilized in solid-state synthesis. Using a novel combination of ex situ XRD on as-synthesized samples, with in situ XRD to monitor the relation between Na content and lattice parameters, we are able to construct a phase diagram of NaxCoO2 between 450 to 750 °C in air and for Na:Co sample ratios ranging from 0.60 to 1.05. Four single phase domains of O3, O′3, P′3, and P2 are revealed based on the XRD analysis. In contrast to previous reports it is found that pure O3, O′3 and P′3 phase can only form at a fixed stoichiometry of x = 1.00, 0.83, and 0.67, respectively, while the P2 phase forms in a slightly larger composition range from 0.68 to 0.76. Galvanostatic charging of O3–Na1.00CoO2 shows several flat and sloping regions on the voltage prof...

[1]  D Carlier,et al.  Electrochemical investigation of the P2–NaxCoO2 phase diagram. , 2011, Nature materials.

[2]  P. Hagenmuller,et al.  Electrochemical intercalation of sodium in NaxCoO2 bronzes , 1981 .

[3]  Jean-Marie Tarascon,et al.  Synthesis, Structure, and Electrochemical Properties of the Layered Sodium Insertion Cathode Material: NaNi1/3Mn1/3Co1/3O2 , 2012 .

[4]  R. Cava,et al.  Low temperature phase transitions and crystal structure of Na0.5CoO2 , 2004, cond-mat/0402255.

[5]  H. Sheu,et al.  Searching for stable Na-ordered phases in single-crystal samples ofγ−NaxCoO2 , 2007, 0708.0280.

[6]  Y. Meng,et al.  An investigation of the sodium patterning in Na(x)CoO(2) (0.5 < or = x < or = 1) by density functional theory methods. , 2008, The Journal of chemical physics.

[7]  Shyue Ping Ong,et al.  Insights into Diffusion Mechanisms in P2 Layered Oxide Materials by First-Principles Calculations , 2014 .

[8]  T. He,et al.  Coupling between electronic and structural degrees of freedom in the triangular lattice conductor NaxCoO2 , 2004, cond-mat/0406570.

[9]  P. Hagenmuller,et al.  Structural classification and properties of the layered oxides , 1980 .

[10]  Shinichi Komaba,et al.  Study on the reversible electrode reaction of Na(1-x)Ni(0.5)Mn(0.5)O2 for a rechargeable sodium-ion battery. , 2012, Inorganic chemistry.

[11]  Hiroaki Yoshida,et al.  NaFe0.5Co0.5O2 as high energy and power positive electrode for Na-ion batteries☆ , 2013 .

[12]  Zhonghua Lu,et al.  In Situ X-Ray Diffraction Study of P 2 ­ Na2 / 3 [ Ni1 / 3Mn2 / 3 ] O 2 , 2001 .

[13]  Gerbrand Ceder,et al.  Electrochemical properties of NaNi1/3Co1/3Fe1/3O2 as a cathode material for Na-ion batteries , 2014 .

[14]  Yoyo Hinuma,et al.  Temperature-concentration phase diagram of P 2 -Na x CoO 2 from first-principles calculations , 2008 .

[15]  Xin Li,et al.  Direct visualization of the Jahn-Teller effect coupled to Na ordering in Na5/8MnO2. , 2014, Nature materials.

[16]  C. Delmas,et al.  On the NaxNi0.6Co0.4O2System: Physical and Electrochemical Studies , 1996 .

[17]  B. Lake,et al.  Patterning of sodium ions and the control of electrons in sodium cobaltate , 2005, Nature.

[18]  Shinichi Komaba,et al.  P2-type Na(x)[Fe(1/2)Mn(1/2)]O2 made from earth-abundant elements for rechargeable Na batteries. , 2012, Nature materials.

[19]  R. Rosenfeld.  Nature , 2009, Otolaryngology--head and neck surgery : official journal of American Academy of Otolaryngology-Head and Neck Surgery.

[20]  Ichiro Terasaki,et al.  Large thermoelectric power in NaCo 2 O 4 single crystals , 1997 .

[21]  C. Delmas,et al.  High-temperature phase transition in the three-layered sodium cobaltiteP′3-NaxCoO2(x∼0.62) , 2008 .

[22]  Anubhav Jain,et al.  Voltage, stability and diffusion barrier differences between sodium-ion and lithium-ion intercalation materials , 2011 .

[23]  Xiqian Yu,et al.  Phase transition behavior of NaCrO2 during sodium extraction studied by synchrotron-based X-ray diffraction and absorption spectroscopy , 2013 .

[24]  Kazunori Takada,et al.  Superconductivity in two-dimensional CoO2 layers , 2003, Nature.

[25]  T. R. Jow,et al.  Rechargeable Electrodes from Sodium Cobalt Bronzes , 1988 .

[26]  Gerbrand Ceder,et al.  Electrochemical Properties of Monoclinic NaNiO2 , 2011 .

[27]  T. Kuhn,et al.  Heat transport in ultrathin dielectric membranes and bridges , 2004 .

[28]  P. Hagenmuller,et al.  Sur de nouveaux bronzes oxygénés de formule NaχCoO2 (χ1). Le système cobalt-oxygène-sodium , 1973 .

[29]  Y. Morii,et al.  層状コバルタイトβ‐NaxCoO2の結晶構造,電気的性質及び磁気的性質 , 2002 .

[30]  Anton Van der Ven,et al.  First-Principles Investigation of Phase Stability in the O2-LiCoO2 System , 2003 .

[31]  C. Delmas,et al.  Sodium ion mobility in Na(x)CoO2 (0.6 < x < 0.75) cobaltites studied by 23Na MAS NMR. , 2009, Inorganic chemistry.

[32]  J. Akimoto,et al.  Single-crystal growth, crystal and electronic structure of NaCoO2 , 2003 .

[33]  Y. Morii,et al.  Crystal structure, electric and magnetic properties of layered cobaltite β-NaxCoO2 , 2002 .

[34]  Y. Meng,et al.  An advanced cathode for Na-ion batteries with high rate and excellent structural stability. , 2013, Physical chemistry chemical physics : PCCP.