Ad. Robertson et al., M3-MODIFIED LIMN2O4 SPINEL INTERCALATION CATHODES .1. ADMETAL EFFECTSON MORPHOLOGY AND ELECTROCHEMICAL PERFORMANCE(), Journal of the Electrochemical Society, 144(10), 1997, pp. 3500-3505
Low levels of trivalent cations were utilized to stabilize LiMn2O4 spi
nel cathode materials against capacity decline during electrochemical
cycling. Of the several single-phase products obtained, only those wit
h Cr3+ and Ga3+ prevented capacity fade, and only LiCr0.02Mn1.98O4 exh
ibited acceptable initial reversible capacity. The external particle m
orphology was unchanged by the preparation or the admetal, and the int
ernal structures were all converted to cong tou (onion) configurations
during product synthesis. Grain size played a surprising role in cath
ode performance: <25 mu m material had at least 10% lower capacity tha
n larger or as-prepared Cr-doped LiMn2O4.