正极材料单质硫在LiCF3SO3/DOL+DME电解液中的放电性能

研究了单质硫在1 mol/L LiCF3SO3/DOL DME电解液中的倍率放电性能.结果表明:单质硫的首次放电容量随着放电倍率增大呈现先增后减的趋势.单质硫具有良好的充放电性能,在0.6 mA/cm2的充放电电流密度下,首次放电比容量为972 mAh/g,第50次循环的放电比容量达到605 mAh/g.单质硫的低电压平台能够提供约70%的放电总容量,但低电压平台容量衰减速率较快,平均容量衰减率为0.8%.循环伏安实验的结果表明:在1 mo]/L LiCF3SO3/DOL DME电解液中,单质硫的还原反应为浓差扩散过程,在峰电位1.90 V低电位处的第2还原反应产生固相硫化锂,引起电极钝化现象.

Discharge performance of cathode material elemental sulfur in LiCF3SO3/DOL+DME electrolyte

Rate discharge performance of elemental sulfur in 1 mol/L LiCF3SO3/DOL DME electrolyte was investigated.The results showed that the initial discharge capacity increased at first and then decreased with the discharge current density increasing.Elemental sulfur exhibited a favorable charge-discharge performance,the initial discharge specific capacity was 972 mAh/g and the discharge specific capacity at the 50th cycle was 605 mAh/g at the charge-discharge current density of 0.6 mA/cm2.The low discharge voltage plateau for elemental sulfur could offer about 70% of total discharge capacity,however,the low discharge voltage plateau capacity fading was more serious and average capacity fading rate was 0.8%.The CV experiment result indicated that the reduction of elemental sulfur in 1 mol/L LiCF3SO3/DOL DME electrolyte was affected by a diffusion-controlled process,the second reduction located in low potential range of 1.90 V(peak potential) resulted in solid phase lithium sulfide and passivation phenomenon of the electrode.