修饰四氧化三锰对尖晶石锰酸锂电化学性能的影响

Effect of Modified Trimanganese Tetroxide on Electrochemical Performance of Spinel Lithium Manganate

以硫酸锰为原料,以十六烷基三甲基溴化铵为修饰剂,通过络合沉淀法制备四氧化三锰,再通过高温固相法合成锰酸锂正极材料,探讨了修饰剂用量对四氧化三锰形貌、粒度和锰酸锂正极材料放电比容量的影响。结果表明:未加修饰剂时,制备的四氧化三锰颗粒团聚现象严重;当修饰剂十六烷基三甲基溴化铵质量浓度为3.0 g/L时,制备的修饰四氧化三锰颗粒大小均匀、分散无团聚。用自制的修饰四氧化三锰制备尖晶石锰酸锂,并与市场销售的3种四氧化三锰制备的尖晶石锰酸锂进行了性能对比,结果表明,修饰四氧化三锰制备的锰酸锂电化学性能更优,首次放电比容量达到120.43 mAh/g,1C下循环50次容量保持率为96.79%。

With manganese sulfate as raw material and hexadecyl trimethyl ammonium bromide as modifier,trimanganese tetroxide was synthesized by complex-precipitation method,with which lithium manganate cathode material was then synthesized by high-temperature solid-state reaction.The effects of modifier amount on the morphology and particle size of trimanganese tetroxide and the specific discharge capacity of lithium manganate cathode material were all discussed.Results show that serious particle agglomeration can occur in the trimanganese tetroxide synthesized without modifier.With 3.0 g/L hexadecyl trimethyl ammonium bromide as the modifier,the synthesized trimanganese tetroxide has uniform particle size,and is dispersed without any agglomeration.Spinel lithium manganate was synthesized with the self-made modified trimanganese tetroxide,and then compared with the spinel lithium manganate synthesized with three kinds of trimanganese tetroxide available on the market.The results show that the lithium manganate synthesized with the self-made modified trimanganese tetroxide can present better electrochemical performance,delivering an initial discharge capacity of 120.43 mAh/g,with a retention rate of 96.79%after 50 cycles at 1C.