Na||Sb-Pb-Sn液态金属电池电极的价电子结构与热-电性能计算  

Calculation of thermic and electric properties and valence electron structure for metallic electrodes of Na||Sb-Pb-Sn liquid metal battery

作　　者：张健[1] 王心桥 苏彤 陈英 郭永权[1] Zhang Jian;Wang Xin-Qiao;Su Tong;Chen Ying;Guo Yong-Quan(School of Energy Power and Mechanical Engineering,North China Electric Power University,Beijing 102206,China)

机构地区：[1]华北电力大学能源动力与机械工程学院,北京102206

出　　处：《物理学报》2021年第8期37-46,共10页Acta Physica Sinica

基　　金：国家重点研发计划(批准号:2018YFB0905600)资助的课题。

摘　　要：应用固体与分子经验电子理论系统地研究液态金属池Na||Sb-Pb-Sn电极的价电子结构与热、电性能.研究结果表明:电极合金的价电子结构与其性能密切关联.阴极合金Na_(1–x)IA_x (IA=K, Rb, Cs)的晶格电子随着掺杂量的增加而减少,诱发合金的熔点、结合能随掺杂量的增加而降低. Na离子输运到阳极,与阳极Sb-Sn-Pb形成产物NaSb_3, NaSn, Na_(15)Sn_4, NaPb.其理论熔点与实验相符. NaSb_3的平均晶格电子数最少,开路电压最高.研究表明:对于Na||Sb-Pb-Sn液态金属电池体系而言,晶格电子扮演重要的角色,可以调控电极的热、电性能.The valence electron structures and thermal and electric properties of Na||Sb-Pb-Sn liquid metal battery are systematically studies with solid and molecular empirical electron theory(EET).The theoretical studies show that the thermal and electric properties are strongly related to the valence electron structure of electrode.The cathodic alloys Na1–xIAx(IA=K,Rb,Cs)are designed by doping IA group alkali metals(K,Rb,Cs)into Na electrode since the melting points of IA group metals(K,Rb,Cs)are all lower than that of sodium.The theoretical bond lengths and cohesive energy of cathodic alloys Na1–xIAx match the experimental ones well.The theoretical studies show the decreasing tendency of melting point,cohesive energy and electric potential with increasing doping content x in Na1–xIAx alloys,which is due to the modulation of valence electron structure of IA group dopants.According to the analyses of valence structures,the number of lattice electrons decreases with the increasing of the doping content x for the cathodic alloy and causes the melting point,electric potential and cohesive energy to decline.It reveals that the IA group dopant modulates the valence electron structure of cathodic alloy,and induces the electron transformation from lattice electron to covalent electron in s orbital.The anode products such as NaSb3,NaSn,Na15Sn4 and NaPb are formed by transporting Na ions into the anode alloy Sb-Sn-Pb.The calculated bond-lengths and melting points fit the observed ones well for these anode products.Owing to their complex structures with various atomic occupations in unit cell,the thermal property or electric property is not only relative to lattice electron,but also depends on the covalent electron.The sublattice plays an important role in the forming of the four anode products.The lattice electrons are supplied by Na at 4f sites in Na3Sb,Na at 16e and Sn at 32g sites in NaSn,Sn at 16c and Na at 48e sites in Na15Sn4,and Na at 16f and Pb at 32g sites in NaPb,respectively.The open-gate voltage is closely relate

关 键 词：固体与分子经验电子理论 液态金属电池 价电子结构 开路电压 

分 类 号：TM91[电气工程—电力电子与电力传动]