Electrochemical cell with new fast ion conductors
OwnerJohn B. Goodenough, Koichi Mizuchimainventors
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Abstract
There is interest in the use of solid-solution electrodes as a way of meeting the problems of conventional batteries; Li.sub.a TiS.sub.2 where O<a<1 is known in this respect and may be made by high temperature preparative routes. Fast ion conductors of the formula A.sub.x M.sub.y O.sub.2 where A is Li, Na or K, M is a transition metal e.g. Co or Ni, <x<1 and y.apprxeq.1 have been made for this purpose according to the invention. They cannot be made by high temperature routes when x is substantially less than 1 owing to stability problems. In the invention, they have been made by electrochemical extraction of A.sup.+ ions from compounds of the formula A.sub.x' M.sub.y O.sub.2 where O<x'<1, carried out at low temperature.
Claims7
An ion conductor, of the formula A.sub.x M.sub.y O.sub.2 and having the layers of the .alpha.-NaCrO.sub.2 structure, in which formula A is Li, Na or K;
- M is a transition metal;
- x is less than 1 and y is approximately equal to 1, the A.sup.+ cation vacancies in the ion conductor having been created by A.sup.+ cation extraction.
An ion conductor of the formula Li.sub.x M.sub.y O.sub.2 and having the layers of the .alpha.-NaCrO.sub.2 structure, in which formula x is 0.8 or less, y is approximately equal to 1 and M is Co or Ni.
Dependencies are inferred from the claim text.