以L iOH.H2O和Mn(CH3COO)2.2H2O作原料,应用微波-固相两段烧结法合成具有L i4Mn5O12结构特征,组成为L i3.22Na0.569Mn5.78O12.0的锂离子电池正极材料.XRD分析表明,在380℃的后处理温度下,微波烧结前处理有利于生成纯L i4Mn5O12尖晶石相.充放电实验表明,在4.5~2.5V电压区间,新制样品的初始放电容量为132 mAh.g-1,100循环的容量衰减率为6.8%;4个月存放样的初始放电容量为122 mAh.g-1,100循环的容量衰减率为17.4%.表现出较好的充放电性能和循环寿命.微波烧结使样品的Mn-O键被加强.
By selecting LiOH·H_(2)O and Mn(CH_(3)COO)_(2)2H_(2)O as starting-materials,the positive materials with the structure characterization of Li_(4)Mn_(5)O_(12)and composition of Li_(3.22)Na_(0.569)Mn_(5.78)O_(12.0)were prepared by two-phase sintering method consisted of microwave and solid-state sintering processes.XRD patterns data showed that a pure Li_(4)Mn_(5)O_(12)phase was obtained by the fore-treatment of microwave sintering and the post-treatment of the solid-state sintering at 380℃.The charge-discharge tests showed that the newly prepared sample exhibited an initial capacity of 132 mAh·g~(-1)and its capacity faded after 100 cycles was 6.8% lower as compared with 1st cycle capacity in the voltage range of 4.5 to 2.5 V.The sample stored for 4 months exhibited an initial capacity of 122 mAh·g~(-1)and its capacity faded after 100 cycles was 17.4% lower than its 1st cycle capacity in the same voltage range.The Mn-O bond of the sample strengthened by microwave sintering process.
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