Compositions for fast alkali-metal-ion transport
AssigneeMassachusetts Institute of Technology
InventorsHenry Y-P Hong, John B. Goodenough
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Abstract
Fast alkali-metal-ion transporters are provided having low resistivities and low-activation-energy mobilities at temperatures at which alkali metals are molten. The novel compounds promote alkali-metal-ion transport in three dimensions within their crystalline structure and have the general formula: A.sub.n X.sub.2 (ZO.sub.4).sub.3 or A.sub.m (Z'.sub.2 O.sub.4) wherein A is potassium, sodium or lithium, Z' is a tetrahedrally coordinated cation or mixtures thereof, X is an octahedrally coordinated cation or mixtures thereof, n is a number greater than 1 and less than 4, m is a number from 1 up to 2 and Z' is a mixture of at least two Z' cations. BACKGROUND OF THE INVENTION
Claims8
A crystalline compound which promotes fast alkali metal-ion transport in three dimensions having the formula selected from the group consisting of:
- A.sub.n X.sub.2 (ZO.sub.4).sub.3
- and
- A.sub.m (Z'.sub.2 O.sub.4).sub.3
- wherein A is potassium, sodium or lithium, Z is a tetrahedrally coordinated cation or mixtures thereof not reducible by molten alkali metal, X is an octahedrally coordinated cation or mixtures thereof not reducible by molten alkali metal, n is a number greater than 1 and less than 4, m is a number from 1 up to 2 and Z' comprises at least two Z cations.
The compound of the formula:
- K.sub.2-2x Mg.sub.1-x Si.sub.1+x O.sub.4
- wherein x is a number greater than 0 and less than 0.5.
Dependencies are inferred from the claim text.