10mmol/L LiPF_(6)电解液下锂硫空气电池阳极腐蚀及放电性能分析

Analysis of Anodic Corrosion and Discharge Performance of Lithium Sulfur Air Battery in 10 mmol/L LiPF Electrolyte

为了提高锂硫空气电池阳极在3.5%NaCl电解质下的放电性能,通过在电解质中添加10 mmol/L LiPF_(6)的方式研究其腐蚀和放电性能。研究结果表明:当在3.5%NaCl溶液内加入10 mmol/L的LiPF_(6)之后,4 d后阳极腐蚀速率发生明显减小,由0.350 mg/(cm^(2)·h)减小到了0.024 mg/(cm^(2)·h),显著增强了阳极耐蚀能力。加入LiPF_(6)后,阳极达到了更高的腐蚀电位,其中阳极极化曲线斜率保持基本恒定。加入LiPF_(6)后获得了更小的阳极腐蚀电流密度,从44.26μA/cm^(2)下降到了20.08μA/cm^(2),显著增强了阳极耐蚀能力。加入LiPF_(6)能够明显提高放电电压,在电流密度为14 mA/cm^(2)的情况下放电电压由0.55 V增大至0.74 V,这表明LiPF_(6)能够显著增强电极放电活性,降低锂合金放电反应阶段的自腐蚀速率。加入LiPF_(6)之后,腐蚀表面主要形成Mg(OH)_(2),同时还有少部分Al(OH)_(3)与PbO_(2)生成。

In order to improve the discharge performance of lithium sulfur air battery anode in 3.5%NaCl electrolyte,the corrosion and discharge performance of lithium sulfur air battery anode were studied by adding 10 mmol/L LiPF_(6) into the electrolyte.Results showed that when 10 mmol/L LiPF_(6) was added into 3.5%NaCl solution,the anodic corrosion rate decreased obviously after 4 days,from 0.350 mg/(cm^(2)·h)to 0.024 mg/(cm^(2)·h),indicating that the corrosion resistance of the anode was significantly enhanced.After the addition of LiPF_(6),the anode shifted a higher corrosion potential,and the slope of anode polarization curve remained basically constant.The anodic corrosion current density decreased from 44.26μA/cm^(2) to 20.08μA/cm^(2) by adding LiPF_(6) into the solution,which significantly enhanced the corrosion resistance of the anode.LiPF_(6) significantly increased the discharge voltage from 0.55 V to 0.74 V at the current density of 14 mA/cm^(2).Therefore,LiPF_(6) significantly enhanced the electrode discharge activity and reduced the self-corrosion rate in the discharge reaction stage of lithium alloy.After the addition of LiPF_(6),Mg(OH)_(2 )was mainly formed on the corrosion surface,with a small amount of Al(OH)_(3 )and PbO_(2).