Ionic motion in solid electrolytes: a solid-state NMR study of sodium and lithium in. beta. -alumina

Technical Report · Thu Jan 01 04:00:00 EST 1981

OSTI ID:5192832

Highe, A J

Solid state NMR techniques have been used as a microscopic probe of the structural and dynamical properties of the mobile cations in the solid electrolyte ..beta..-alumina. The first order quadrupole shifts in the (+-3/2 in equilibrium +- 1/2) transitions in the spin 3/2 nuclei sodium and lithium have allowed the electric field gradients (EFG) for the nominal Beevers and Ross (BR) and mid-oxygen (MO) sites to be characterized. The details of the EFG's for and the distribution of cations among BR and MO sites reflect the differences in the potential wells for lithium and sodium in ..beta..-alumina. In particular, unlike sodium, the MO site for lithium is lower in energy than the BR site which results in a different structural arrangement of lithium ions. In sodium ..beta..-alumina, the equilibrium position for sodium in the BR site is displaced from the three-fold symmetry axis. It is believed that this is due to the presence of nearby MO-MO pairs. Furthermore, an activation energy of 0.04 eV is observed for the motion of sodium ions among the displaced BR sites which is associated with the correlated motion of MO-MO pairs. The effects of a second motional process with an activation energy of 0.08 eV are observed in both lithium and sodium spectra which are associated with the motion of cations among BR and MO sites. The interaction of cations in MO-MO pairs was further investigated by observing the effect of varying the ratio of lithium and sodium in mixed lithium-sodium ..beta..-alumina on the distribution of cations among available sites.

• Research Organization: California Inst. of Tech., Pasadena (USA)
• DOE Contract Number: AT03-76ER70015
• OSTI ID: 5192832
• Report Number(s): DOE/ER/70015-T1; ON: DE82019260
• Country of Publication: United States
• Language: English

Related Subjects

25 ENERGY STORAGE
250903* -- Energy Storage-- Batteries-- Materials
Components
& Auxiliaries
36 MATERIALS SCIENCE
360603 -- Materials-- Properties
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
CATIONS
CHALCOGENIDES
CHARGED PARTICLES
ELECTRIC FIELDS
ELECTROLYTES
ION MOBILITY
IONS
LITHIUM IONS
MAGNETIC RESONANCE
MOBILITY
NUCLEAR MAGNETIC RESONANCE
OXIDES
OXYGEN COMPOUNDS
PARTICLE MOBILITY
RESONANCE
SODIUM IONS
SOLID ELECTROLYTES