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以尿素为络合剂,氢氧化锂、醋酸锰等为原料通过水热反应获得颗粒均匀的尖晶石LiMxMn2-xO4(M=Li,Na,Tl)前驱物,然后将前驱物在600℃～700℃间煅烧4h后获得最终产物。实验主要考察了掺杂元素的离子半径和M-O键离解能对产物LiMxMn2-xO4充放电过程中稳定性的影响,以及煅烧温度对材料形貌与结构的影响。结果表明掺杂元素的离子半径与被取代元素的离子半径越接近则掺杂后的材料越稳定,而M-O键离解能的影响则很小。实验发现LiNa0.02Mn1.98O4的综合性能最佳,该样品在室温0.2C倍率的首次放电容量可以达到107mAh.g-1,且不可逆容量衰减小,电池循环20次后容量只衰减了约2.8%。
A uniform spinel LiMxMn2-xO4 (M = Li, Na, Tl) precursor was obtained by hydrothermal reaction using urea as a complexing agent, lithium hydroxide and manganese acetate as raw materials, and then the precursor was calcined at 600 ~ 700 ℃ calcined 4h after the final product was obtained. The experiment mainly investigated the influence of ion radius and M-O bond dissociation energy on the stability of LiMxMn2-xO4 during charging and discharging, and the effect of calcination temperature on the morphology and structure of the material. The results show that the closer the ionic radius of the doping element is to the ion radius of the substituted element, the more stable the doped material, while the effect of M-O bond dissociation energy is very small. The experimental results show that LiNa0.02Mn1.98O4 has the best comprehensive performance. The initial discharge capacity of this sample at 0.2C rate at room temperature can reach 107mAh.g-1, and the irreversible capacity decay is small. After 20 cycles, the capacity declines by only about 2.8% .