A controlled crystallization process was proposed for synthesis of yttrium doped spherical spinel LiMn₂O₄ particles. Its successful preparation started with a carefully controlled crystallization of yttrium doped MnCO₃ by co-precipitation of MnSO₄ and YCl₃ with NH₄HCO₃ and NH₃•H₂O. Mn₂O₃ was obtained by heating MnCO₃ and mixed with Li₂CO₃ to produce yttrium doped spinel LiMn₂O₄. As-prepared samples were characterized by SEM and XRD. Dissolution of manganese in electrolyte was also investigated, resulting in that the dissolution was enhanced by dopant of yttrium. The more yttrium, the larger dissolution, indicating that manganese was activated by yttrium. The activation of manganese led to both enhancement of electrochemical activity and reactivity with electrolyte of manganese. The former improved the elec-trochemical performance of spinel LiMn₂O₄. Contrarily, the latter worsened its performance. 0.5% was a proper amount of doping, and such yttrium doped sample Li(Y_0.005Mn_0.995)₂O₄ had an initial capacity of 130 mAh•g^－1 over that of un-doped one with the capacity retention to reach 92.3% exceeding that of un-doped one at 100th cycle.

Key words: spinel LiMn₂O₄, doping, yttrium, dissolution of manganese, Li-ion battery