二甲基亚砜对有机电解液锂空气电池性能的影响

Influence of DMSO on Performance of Organic Electrolyte Li-air Cells

中文关键词: 锂空气电池 有机电解液 混合溶剂 硝酸锂-二甲基乙酰胺 二甲基亚砜

英文关键词: Li-air cell, organic electrolyte, component solvent, lithium nitrate in the solvent N, N-dimethyl acetamide (LiNO₃-DMA), dimethyl sulfoxide(DMSO)

中文摘要:

      以硝酸锂-二甲基乙酰胺(LiNO₃-DMA)有机电解液体系为基础,向电解液体系添加溶剂二甲基亚砜(DMSO),研究分析了混合溶剂电解液的物化性质、恒流充放电及反应机理。DMSO的添加可以使锂负极形成稳定的固体电解质相界面(SEI)膜,有效增强了LiNO₃-DMA与锂的化学兼容性,降低了极化阻抗,因此循环性能有所提高。截止比容量为1 000 mAh/g_carbon、电流密度为0.2 mA/cm²时可稳定循环40周。SEM及XRD分析表明,LiNO₃-DMA和LiNO₃-DMA/DMSO放电均生成可循环产物Li₂O₂,但DMSO中的疏水性甲基抑制了LiNO₃-DMA中副产物LiOH的生成。此外,LiNO₃-DMA循环过程中生成了含硫化合物,这是导致放电终止的重要原因。

英文摘要:

      Lithium nitrate (LiNO₃) in the solvent N, N-dimethyl acetamide (DMA) was regarded as a base, by adding thereto solvent dimethyl sulfoxide (DMSO), chemical and physical properties of complexing solvent, charging profile and reaction mechanism were investigated. Electrolyte with DMSO added in LiNO₃-DMA is capable of forming a protective solid-electrolyte interphase (SEI) on Li anode, which effectively enhances the chemical compatibility and reduces the polarization resistance of LiNO₃-DMA so that the charging profile has been improved. The Li-air cell stably cycled 40 times with capacity limited to 1 000 mAh/g_carbon at current density of 0.2 mA/cm². SEM and XRD identified the discharge products of both LiNO₃-DMA and LiNO₃-DMA/DMSO are Li₂O₂, but hydrophobic methacrylic in DMSO inhibits formation of by-product LiOH. In addition, during LiNO₃-DMA cycling S-containing compound can be generated which contributes much to discharge termination.