Tuesday, 31 May 2016
Exhibit Hall H (San Diego Convention Center)
Nanostructured manganese dioxides (MnO2) are among the promising materials for high-capacity lithium-ion batteries [1], lithium air batteries [2] and supercapacitors [3], that can be used in electric vehicles and other consumer electronics. Simulated amorphisation recrystallisation method has been successfully used to nucleate and crystallise bulk [4] and nanoporous β-MnO2 [5]. In the current study we demonstrate that nanostructuring of MnO2 results in the exposure of a variety of surfaces to be exposed at the (internal) pores because of the high curvature of the material; the low energy MnO2(101) surface does not dominate the morphology. This nanostructuring facilitates a wide variation of entrance sites into the 1x1 tunnels in contrast to the parent bulk material. In particular, the activation energy associated with Li intercalation/deintercallation into the (101) surface of the bulk material is calculated to be 0.6eV. On the other hand, for the mesoporous material we calculate the activation energy for Li transport and deintercallation to be 0.4eV.
1] B.X. Li, G.X. Rong, Y. Xie, L.F. Huang and C.Q. Feng, Inorg. Chem. 2006, 45, 6404.
[2] A. Débart, A.J. Paterson, J. Bao and P.G. Bruce, Angew. Chem., Int. Ed. 2008, 47, 4521.
[3] W. Wei, X. Cui, W. Chen and D.G. Ivey, Chem. Soc. Rev. 2011, 40, 1697
[4] T.X.T. Sayle, C.R.A. Catlow, R.R. Maphanga, P.E. Ngoepe and D.C. Sayle, J. Crystal Growth, 294,118-129, 2006.
[5] T.X.T. Sayle, R.R. Maphanga, P.E. Ngoepe and D.C. Sayle, J. American Chem. Soc., 131, 6161-6173, 2009.