Syntheses, structure and properties of a new Fillowite-type compound Na0.48Mn1.22PO4

Searching for excellent polyanionic cathode materials for Na-ion batteries attract considerable attention in recent years. Herein, a new polyanionic cathode candidate Na0.48Mn1.22PO4, crystallizing in the space group R-3 with the unit cell parameters of a = 15.3672 (17) angstrom, c = 43.503 (5) angstrom and V = 8896.91 (2) angstrom(3), belonging to the Fillowite-type structure, is reported for the first time. In the structure of Na0.48Mn1.22PO4, the Mn-O connectivity exhibits three-dimensional Mn-O-Mn network. More interestingly, some Mn5O6 clusters embed in the network. Electrochemical tests revealed that Na0.48Mn1.22PO4 can be very effectively cycled against a Na metal electrode with an average voltage of 3.35 V. In addition, The XANES and magnetic tests were also employed for the characterization of the material. (C) 2017 Elsevier B.V. All rights reserved.