Solid Electrolytes

Our group is studying how the fundamental crystal chemistry of intercalation hosts influences the transport of ions through the solid state. We are particularly interested in polyanionic compounds, like sulfates and silicates, which contain rigid subunits consisting of strong covalent bonds between a main group element and its ligands, because of their robust structures and rich compositional phase diagrams. We have done extensive work to demonstrate that these materials exhibit significantly different structural distortions compared to traditional oxide based hosts. Whereas oxides may experience short-range structural distortions to accommodate the volumetric changes required as Li is (de)inserted into the framework, polyanionic hosts must perform cooperative rotations of the rigid subunits in order to satisfy the local bonding within the polyanionic group. This mechanism can be highly beneficial as it is a highly reversible process that maintains the integrity of the structure over thousands of cycles, yet this rigidity may also limit the directions along which ions can hop from site to site, potentially slowing their mobility. 

Selected Publications

Lopez-Bermudez et al. Lithium-ion conductivity in Li6Y(BO3)3: a thermally and electrochemically robust solid electrolyte J. Mater. Chem. A, 2016, 4, 6972 [doi]

Zeier et al. Dependence of the Li-Ion Conductivity and Activation Energies on the Crystal Structure and Ionic Radii in Li6MLa2Ta2O12 ACS Appl. Mater. Interfaces, 2014, 6, 10900 [doi]

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