In this talk I will discuss our research toward chemical and structural engineering of nanomaterials for energy applications. I will discuss our new fabrication of ductile, conducting metal oxide nanosheets using sol-gel chemistry and kinetic demixing. Using this new synthesis method we fabricate alkali cobaltate nanosheets, which are difficult to form as independent nanosheets though conventional chemical exfoliation methods. These nanosheets are more than 10 – 100 times longer than typical metal oxide nanosheets. The synthetic method is low-cost, environmentally benign, and scalable: the bottom-up synthesis produces tens of thousands of nanosheets, which are self-assembled and packed into a macro-scale pellet. The resistivity of the stacks of KxCoO2∙yH2O nanosheets is lower than ~4.7 mΩ∙cm, corresponding to the lowest electrical resistivity in the literature for metal oxide nanosheets longer than 10 microns, and the second lowest overall for metal oxide nanosheets. The NaxCoO2 nanosheet stacks are promising because sodium cobaltate possesses fascinating stoichiometric-dependent properties, such as a high thermoelectric power factor, high electrical conductivity, superconductivity, and candidacy as a cathode material in sodium ion batteries. The nanosheets are ductile, with a bending radius as small as ~5 nm, which to our knowledge has not been previously reported for a ceramic. These metallic oxide nanosheets could be useful electrocatalytic supports since they are conductive, thermally and chemically stable, and ductile.

Metal oxide nanosheets for energy applications

249th National Meeting (2015)

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