Patent ID: 6048645
Filing Date: 2000-04-11
Classification: C01G,C01P,H01M,Y02E

Abstract:
A lithium ion battery which comprises a positive electrode and a negative electrode, said positive electrode comprising a lithium manganese oxide active material which is initially a single phase oxide of lithium (Li) and manganese (Mn) with a tetragonal crystal structure with the lattice parameters a=5.665 .ANG..+-.0.003 .ANG. and c=9.265 .ANG..+-.0.003 .ANG., and containing Li/Mn atomic ratio of greater than or equal to 1.0 and less than or equal to 1.15, nominally Li.sub.2 Mn.sub.2 O.sub.4 ; and when Li ions are deintercalated (extracted) from said Li.sub.2 Mn.sub.2 O.sub.4 at first and second voltage plateaus as said battery is charged, the crystal structure is transformed to a cubic spinel structure characterized by lattice parameter a=8.235 .ANG..+-.0.004 .ANG.; and on subsequent reinsertion and extraction of lithium by cycling said battery at said second voltage plateau, said cubic spinel structure is maintained.