Solid state studies on K2Ti6−xNbxFe2O16 (x = 0 and 1) and lithium insertion into K2Ti6M2O16 (M = Cr, Fe and Ga) and K2Ti5NbFe2O16 hollandite type phases

Marimuthu, Karthikeyan; Smart, Lesley E.; Berry, Frank J.; Varadaraju, U.V.

doi:10.1016/s0254-0584(03)00343-2

Cited by 4 publications

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“…The M is a countercation with a valency of 2+ or 3+ and provides the charge balance for the compound. [24][25][26][27][28][29][30] The hollandites Ba(M 3+ 2 Sn 4+ 6 )O 16 , M ) Ga, In, Cr, 25,26 K 2 (Ga 2 Sn 6 )O 16 , 27 and, recently, K 2 (Mg 2+ Sn 7 )O 16 28 have been prepared and studied for possible use as catalysts and gas sensors. The hollandites crystallize with a tetragonal symmetry, but depending on the A and (M, Sn) ions, monoclinic distortion is also observed.…”

Section: Introductionmentioning

confidence: 99%

“…Tin oxides containing SnO 6 octahedra are encountered in compounds with the hollandite structure, A x (M,Sn) 8 O 16 , where A is a large-size cation like Ba or K, x ≤ 2. The M is a countercation with a valency of 2+ or 3+ and provides the charge balance for the compound. − The hollandites Ba(M 3+ 2 Sn 4+ 6 )O 16 , M = Ga, In, Cr, , K 2 (Ga 2 Sn 6 )O 16 , and, recently, K 2 (Mg 2+ Sn 7 )O 16 28 have been prepared and studied for possible use as catalysts and gas sensors. The hollandites crystallize with a tetragonal symmetry, but depending on the A and (M, Sn) ions, monoclinic distortion is also observed. − The structure consists of double chains of edge-shared (M,Sn)O 6 octahedra that are connected at their corners to form a framework of 1D channels with the 8-fold O-coordination (Figure ).…”

Section: Introductionmentioning

confidence: 99%

“…These so-called 2 × 2 octahedra channels are occupied by the A-cations, represented by filled circles in Figure . The versatile nature of the structure allows Sn 4+ ion to be replaced by other cations such as Ti, V, Cr, Mn, Mo, or Ru, and the M ion can also be Li + . − ,, Presently, we synthesized and characterized the phases K 2 (Li 2/3 Sn 22/3 )O 16 , K 2 (MgSn 7 )O 16 , and K 2 (M 3+ 2 Sn 4+ 6 )O 16 , M = Mn and Fe. These compounds were studied for their electrochemical behavior toward Li metal and to find out their applicability as anodes for LIB.…”

Section: Introductionmentioning

confidence: 99%

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Tin Oxides with Hollandite Structure as Anodes for Lithium Ion Batteries

et al. 2005

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Tin oxides, K2(M,Sn)8O16 (M = Li, Mg, Fe, or Mn), possessing the hollandite crystal structure have been synthesized and characterized by a variety of techniques, and their electrochemical behavior was studied. The compounds K2(Li2/3Sn22/3)O16 (K−Li), K2(Mn2Sn6)O16 (K−Mn), and K2(Fe2Sn6)O16 (K−Fe) are new phases. Rietveld refinement of the powder X-ray diffraction data showed that these Sn-hollandites exhibit a simple tetragonal structure. X-ray photoelectron spectroscopy on (K−Li) and (K−Mg) confirm formal valencies of the ions in the compounds. Galvanostatic cycling versus Li metal in the voltage range of 0.005−1.0 V at the current density of 60 mA/g showed the first cycle charge capacities of 602, 505, 481, and 418 (± 3) mAh/g for (K−Li), (K−Mg), (K−Fe), and (K−Mn), respectively. These values correspond to 3.7−3.0 mol of recyclable Li/mol of Sn. At the end of 50 cycles, (K−Li) and (K−Fe) performed better and retained 78 and 83% of the initial capacity. The (K−Li) also showed good rate capability. The Coulombic efficiency was >98% between 10 and 50 cycles in all cases except (K−Mn) with the average charge and discharge voltages of 0.4−0.5 and 0.25−0.3 V, respectively. Cyclic voltammograms complement the galvanostatic results. Impedance spectral data on the (K−Li) versus Li at different voltages during the 1st and 15th discharge−charge cycle have been analyzed and interpreted.

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