Philip Lightfoot

Crystal Structure of the Polymer Electrolyte Poly(ethylene oxide)3:LiCF3SO3.

Ionically conducting polymers (polymer electrolytes) are under intensive investigation because they form the basis of all solid-state lithium batteries, fuel cells, and electrochromic display devices, as well as being highly novel electrolytes. Little is known about the structures of the many crystalline complexes that form between poly(ethylene oxide) and a wide range of salts. The crystal structure is reported of the archetypal polymer electrolyte poly(ethylene oxide)3:LiCF3SO3, which has been determined from powder x-ray diffraction data. The poly(ethylene oxide) (PEO) chain adopts a helical conformation parallel to the crystallographic b axis. The Li+ cation is coordinated by five oxygen atoms—three ether oxygens and one from each of two adjacent CF3SO3- groups. Each CF3SO3– in turn bridges two Li+ ions to form chains running parallel to and intertwined with the PEO chain. There are no interchain links between PEO chains, and the electrolyte can be regarded as an infinite columnar coordination complex.

Ferroelectric-paraelectric transition in BiFeO3: crystal structure of the orthorhombic beta phase.

A detailed investigation using variable temperature powder neutron diffraction demonstrates that

Ferroelectric-Paraelectric Transition inBiFeO3: Crystal Structure of the OrthorhombicβPhase

{\mathrm{BiFeO}}_{3}

Solid-state transformations of zinc 1,4-benzenedicarboxylates mediated by hydrogen-bond-forming molecules.

undergoes a phase transition from the ferroelectric

Orientation dependence of ferroelectric properties of pulsed-laser-ablated Bi4−xNdxTi3O12 films

\ensuremath{\alpha}

Pressure-induced charge transfer and dTc/dP in YBa2Cu3O7−x

phase (rhombohedral,

Cation disorder in ferroelectric Aurivillius phases of the typeBi2ANb2O9(A=Ba, Sr, Ca)

R3c

The widespread occurrence of negative thermal expansion in zeolites

) to a paraelectric

Structural changes of superconducting YBa2Cu4O8 under high pressure

\ensuremath{\beta}

The Polar Phase of NaNbO3: A Combined Study by Powder Diffraction, Solid-State NMR, and First-Principles Calculations

phase (orthorhombic,