基于V2C催化剂的混合电解质锂空气电池催化机理研究

Study on Catalytic Mechanism of Hybrid Electrolyte Lithium-Air Battery Based on V 2C Catalyst

氧还原反应(ORR)和析氧反应(OER)催化活性的提高可以显著提高混合电解质锂空气电池的性能。二维材料V2C(MXenes)具有丰富的组成、高比表面积和强稳定性等特点,受到广泛关注。本工作基于密度泛函理论(DFT)的第一性原理方法,研究了V2C的电子性质、碱性条件下氧气在V2C表面的最佳吸附位点和氧气在V2C表面的氧化还原过程,计算了V2C的自由能和过电势,最后将其与混合电解质锂空气电池常用的MnO2催化剂进行了比较。结果表明,V2C作为混合电解质锂空气电池催化剂时,比常用的MnO2催化剂的过电势更小,说明该催化剂可以提高电极的催化性能,是一种前景良好的ORR和OER双功能催化剂。

The improved catalytic activity of oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)can significantly improve the performance of hybrid electrolyte lithium-air batteries.The two-dimensional material V 2C(MXenes)has attracted much attention due to its rich composition,high specific surface area,and strong stability.Based on the first principles approach of density functional theory(DFT),this work investigated the electronic properties of V 2C,the optimal adsorption sites of oxygen on the V 2C surface under alkaline conditions,and the redox process of oxygen on the V 2C surface,calculated the free energy and overpotential,and finally compared it with the MnO 2 catalyst commonly used in hybrid electrolyte lithium-air batteries.The results showed that V 2C has a lower overpotential than the commonly used MnO 2 catalyst when used as a catalyst for hybrid electrolyte Li-air batteries,indicated that the catalyst can improve the catalytic performance of the electrode and was a promising bifunctional catalyst for ORR and OER.