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Synthesis and Structure of the Sodium Phosphidosilicate Na 2 SiP 2
Author(s) -
Haffner Arthur,
Hatz AnnaKatharina,
Hoch Constantin,
Lotsch Bettina V.,
Johrendt Dirk
Publication year - 2020
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201901083
Subject(s) - chemistry , crystal structure , crystallography , electrochemistry , sodium , ionic conductivity , ionic bonding , stoichiometry , dielectric spectroscopy , ion , solid state , inorganic chemistry , electrode , organic chemistry , electrolyte
Ion conductors of light alkaline metals based on earth‐abundant elements are important components for all‐solid‐state batteries. The new sodium‐rich phosphidosilicate Na 2 SiP 2 was synthesized by solid state reaction of stoichiometric amounts of the elements at 973 K and characterized by single‐crystal X‐ray diffraction (space group Pccn (no. 56), a = 12.7929(5) Å, b = 22.3109(9) Å, c = 6.0522(2) Å and Z = 16) and solid‐state NMR under MAS conditions. The compound forms dark‐red twinned crystals, and its crystal structure contains edge‐sharing SiP 4 tetrahedra connected to infinite ∞ 1 [SiP 4/2 ] chains. The sodium ions between the chains are fairly mobile. Electrochemical impedance spectroscopy shows a total ionic conductivity of σ (Na + , 373 K) = 2.3 ? 10 –6 Scm –1 with an activation energy of E a = 0.43 eV, and the galvanostatic polarization reveals mixed conduction behavior with a transference number of 0.8.