锂-空气电池的高性能空气电极的性能研究

摘要

锂-空气电池是比能量最高的二次电池,已成为当今化学电源领域的研究热点.在锂-空气电池的各个组件中,空气电极的设计和制备是进一步提高锂-空气电池性能的关键.以简单的合成方法制备了一种具有高催化活性的镍酸镧(LaNiO3)催化剂,利用Super P作为催化剂载体制备了一种新型空气电极.实验结果表明,含有LaNiO3催化剂的锂-空气电池具有良好的充放电性能,放电电压平台为2.59 V,放电容量达到1 109 mAh·g-1.比较了2种碳材料(Super P和GNS)作为催化剂载体的空气电极对电池充放电性能的影响,发现多孔性的空气电极结构更有利于电池性能的提高.此外,还分析了控制电解液(1 mol·L-LiTFSI/TEGDME)中水含量的必要性.由Super P、LaNiO3及水含量小于1×10-5的电解液(1 mol·L-LiTFSI/TEGDME)组装成的锂-空气电池具有良好的循环性能,循环第五圈的容量保持率为96.21％,且不出现电压平台的明显变化.%Lithium-air batteries with the highest specific energy has become a hot research topic in the field of chemical power source.Among the components of lithium-air batteries,design and preparation of air electrode is a key factor for improving the performance of lithium-air batteries.A new catalyst of LaNiO3 with high catalytic activity is prepared by a simple synthetic method.The experimental results show that the lithium-air battery with LaNiO3 catalyst has a good charge-discharge performance,which discharge capacity is 1 109 mAh·g-1 and discharge voltage platform is 2.59 V.The impact of two kinds of carbon materials (Super P and GNS) as the catalyst carrier on the charge-discharge performance of lithium air battery is studied in detail.It can be found that the porous structure of electrode is more advantageous to the improvement of performance of lithium-air battery.Furthermore,the necessity of controlling water content in the electrolyte (1 mol.L-1 LiTFSI/TEGDME)is also discussed.A good cyclic performance of lithium air batteries with LaNiO3/Super P air electrode can be obtained in an electrolyte (water content ＜ 1 × 10-5).The capacity retention of lithium air batteries after the fifth cycle is 96.21％.There is no obvious change for the voltage platform.