New doped Li-M-Mn-O (M = Al, Fe, Ni) spinel as cathodes for rechargeable 3 V lithium batteries

被引:28
作者
Morales, J [1 ]
Sanchez, L [1 ]
Tirado, JL [1 ]
机构
[1] Univ Cordoba, Fac Ciencias, Lab Quim Inorgan, E-14004 Cordoba, Spain
关键词
doped manganese spinels; lithium; lithium battery; electrochemical intercalation reaction;
D O I
10.1007/s100080050120
中图分类号
O646 [电化学、电解、磁化学];
学科分类号
081704 ;
摘要
The electrochemical behaviour of new doped Li-M-Mn-O (M = Al, Fe, Ni) spinel oxides in liquid electrolyte lithium cells was studied. The insertion electrode materials were obtained by heating stoichiometric amounts of thoroughly mixed LiOH and MxMn1-xCO3 (M = Fe, Ni; x = 0.08-0.15) or AlxMn1-x(CO3) (OH)(y), in the case of Al, at 380 degrees C in air for 20 h. The transition metal-doped samples, particularly those containing Ni or obtained at low temperatures, where the resulting spinel was cation-deficient and highly disordered, exhibited the best cycling performance in the potential window 3.3-2.3 V. Cell capacity was retained by 80% after 200 cycles. Capacity fading was observed on increasing the firing temperature, together with improved crystallinity and the disappearance of cation vacancies. This impaired electrochemical behaviour is ascribed to a Jahn-Teller effect, which induces an X-ray-detectable cubic-tetragonal phase transition upon lithium insertion. The phase transition was undetectable in the low-temperature samples. The influence of the Jahn-Teller distortion is thus seemingly lessened by a highly disordered structure.
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页码:420 / 426
页数:7
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