锌离子电池抗枝晶锌合金负极的第一性原理计算

First-principles Calculation of Anti-dendritic Zinc Alloy Anodes for Zinc-ion Batteries

锌离子电池由于具有较高的能量密度、成本低廉,因此在大规模储能领域具有广阔的应用前景。然而,锌金属负极存在的枝晶问题导致电池循环寿命缩短,严重制约了其实际应用。使用第一性原理计算研究了5种锌合金负极对枝晶的抑制作用。结果表明不同结构Zn吸附能的顺序为Zn>Zn_(0.5)Ni_(0.5)>Zn_(0.5)Ti_(0.5)>Zn_(0.5)Y_(0.5)>Zn_(0.5)Cu_(0.5)>Zn_(0.5)Ag_(0.5),Zn解离能的顺序为Zn_(0.5)Ni_(0.5)>Zn_(0.5)Cu_(0.5)>Zn_(0.5)Y_(0.5)>Zn_(0.5)Ag_(0.5)>Zn_(0.5)Ti_(0.5)>Zn。Zn吸附能越高预示着Zn沉积的速度越快,而Zn解离能越低预示着腐蚀速度越快。因此加入合金元素可以减少电极表面上枝晶的形成和增强电极的防腐蚀性能。电子态密度和d带中心的结果表明Zn的吸附和解离能与合金表面的电子结构有较强的关联性。计算结果可以解释Ag、Cu与Zn合金负极有较好性能的实验结果,同时也筛选出Zn和Y合金也是一种比较好的锌离子电池负极材料。

Due to their high energy density and low cost,zinc-ion batteries have broad application prospect in the field of large-scale energy storage.However,the dendrite problem of Zn metal anode seriously restricts its practical application.First-principles calculations were used to investigate the inhibition of dendrites by five kinds of zinc alloy anodes.The results show that the order of Zn adsorption energy is Zn>Zn_(0.5)Ni_(0.5)>Zn_(0.5)Ti_(0.5)>Zn_(0.5)Y_(0.5)>Zn_(0.5)Cu_(0.5)>Zn_(0.5)Ag_(0.5).The order of Zn dissociation energy is Zn_(0.5)Ni_(0.5)>Zn_(0.5)Cu_(0.5)>Zn_(0.5)Y_(0.5)>Zn_(0.5)Ag_(0.5)>Zn_(0.5)Ti_(0.5)>Zn.A higher Zn adsorption energy indicates a faster Zn deposition rate,while a lower Zn dissociation energy indicates a faster corrosion rate.Therefore,adding alloy elements can reduce the formation of dendrites on the electrode surface and enhance the corrosion resistance of the electrode.The results of the density of states and the d-band center indicate that the adsorption and dissociation energies of Zn are strongly related to the electronic structure of the alloy surface.Our calculation results explain the experimental results that Ag and Cu alloy elements have better performance,and also point out that the alloy of Zn and Y may also be a good anode material for Zn-ion batteries.