低温钠离子电池有机正极与电解液的兼容性

Compatibility of organic cathode with electrolyte for low-temperature sodium-ion battery

钠离子电池电极材料和电解液的发展越来越成熟,但低于0℃环境下的性能仍不理想,其中,电极/电解液界面的稳定性会在很大程度上影响低温下电池内部的动力学过程。选用苝3,4,9,10-四羧基二氢化物作为正极材料,搭配3种普适性的电解液组装半电池,进行不同温度下的性能测试。电解液为1 mol/L NaClO_(4)/EC+PC(体积比1∶1)+5%氟碳酸乙烯酯(FEC)的半电池在常温与低温下均具有较好的电化学性能,并具有高的氧化还原稳定性和低的电荷转移电阻,-20℃下,以50 mA/g的电流在1.5~3.5 V循环50次,可保持94.5 mAh/g的比容量,说明电解液与电极之间的兼容性较好。

The electrode materials and electrolyte of sodium-ion battery were developed more maturely,but its performance was still undesirable below 0 ℃,which the dynamics process inside the batteries at low-temperature would be greatly affected by the stability of the electrode/electrolyte interface.Perylene 3,4,9,10-tetracarboxylic dihydride was selected as the cathode material and the assembled half cells were tested at different temperatures with three universal electrolytes.The half cell using 1 mol/L NaClO_4/EC+PC(volume ratio was 1∶1) +5% FEC as electrolyte showed good electrochemical performance at room and low-temperatures,as well as high redox stability and low charge transfer resistance.The specific capacity of 94.5 mAh/g could be maintained after 50 cycles at a current of 50 mA/g in 1.5-3.5 V at-20 ℃,indicating good compatibility between electrolyte and electrode.