高电压电解液对富锂锰动力电池性能的影响

富锂锰基材料xLi_2MnO_3·(1-x)LiMO_2(0x1,M=Mn、Co、Ni)是由Li_2MnO_3和LiMO_2形成复合结构的新型材料,以其高比容量、高电压、高能量密度、低成本、安全性能良好等优势成为新一代的动力锂离子电池正极材料。研究了三种不同的高电压电解液(简写为Ⅰ、Ⅱ、Ⅲ)对富锂锰动力电池的首次充放电、储存性能、倍率放电性能以及低温放电性能的影响。结果表明,不同电解液制备的电池首次充放电效率均较小(约为68%),但其第二周、第三周的充放电效率分别达到96%和98%,与首次充放电效率相比,提高了30%左右;储存30天后,Ⅰ电解液的电池自放电较大,开路电压下降了0.66 V,且储存后的放电容量下降了206.1 mAh;在0.2 C和3 C放电条件下,Ⅱ电解液制备的电池放电容量明显高于其他两种电解液电池,具有较好的倍率放电性能;同时,以0.2 C放电,Ⅲ电解液制备的电池在低温0℃放电容量较常温容量下降幅度最小。因此,Ⅲ电解液具有更优异的电化学性能。

Influence of high voltage electrolyte on performance of lithium-rich manganese power battery

The new lithium-rich manganese-based material xLi2MnO3·(1-x)LiMO2(0＜ x ＜1,M=Mn、Co、Ni) which was composed of Li2MnO3 and LiMO2 had become a new generation cathode material of power lithium ion battery,due to its excellent performances of high capacity,high voltage,high energy density,low cost and safety etc.Effect of three different kinds of high voltage electrolyte (short for Ⅰ、Ⅱ、]]) on the first time charge-discharge,storage performance,rate discharge and low temperature performance of lithium-rich manganese-based power battery was studied.The results show that the first time charge-discharge rates of battery made of different kinds of electrolyte are all small (about 68％),the charge-discharge rate increases to 96％ at the second week and 98％ at the third week,which is 30％ more than the first time.After 30 days of storage,battery made of electrolyte Ⅰ self-discharge of large,the open circuit voltage decreased by 0.66 v,and the discharge capacity decreased by 206.1 mAh.At 0.2 C and 3 C,battery made of electrolyte Ⅲ had good rate discharge performance,its discharge capacities were obviously larger than the other two,discharge capacity of battery made of electrolyte]]Ⅲ decreased less at 0 ℃C than at room temperature.So electrolyte Ⅲ had more excellent electrochemical performance.