Crystal Growth,Preparation, Structure and Electrochemical Properties of Alluaudite-type NaMnV_2(PO_4)_3

Alluaudite-type NaMnV2(PO4)3 single crystal was successfully synthesized in the NaCl molten-salt media. The single-crystal diffraction data analysis shows that NaMnV2(PO4)3 crystallizes in monoclinic C2/c space group with a = 12.098(2), b = 12.415(2), c = 6.4543(11) ?, β = 114.614(2)°, V = 881.3(3) ?3, Mr = 464.64, Dc = 3.50158 g/cm3, μ(Mo Kα) = 4.046 mm-1, F(000) = 892.4 and Z = 2. The structure consists of MnO6, VO6 octahedra and PO4 tetrahedra, which form a three-dimensional architecture with two sets of large Na+ tunnels. The intercalation/deintercalation properties of NaMnV2(PO4)3 as positive and negative electrodes were tested in sodium batteries.