Theoretical investigation of lithium ions’ nucleation performance on metal-doped Cu surfaces

Abstract

Lithium metal batteries (LMBs) of an ultrahigh theoretical energy density have attracted lots of attentions for a wide range of practical applications. However, there are still numerous challenges in LMBs system, such as poor cycling performance, complicated interfacial reactions, low Coulombic efficiency, and uncontrollable lithium dendrites. Understanding Li+ ions' nucleation mechanism is essential to tackle the uncontrolled growth of lithium dendrites. However, the nucleation behavior of Li+ ions is interfered by the structural complexities of existing substrates during the reduplicative plating/stripping process and the rational mechanism of uniform nucleation of Li+ ions has not been clearly understood from the theoretical point of view. In our work, first-principles theoretical calculations are carried out to investigate the Li+ ions nucleation performance on metal-doped Cu surfaces (MDCSs) and the key descriptors that determines the properties of various MDCSs are systematically summarized. It is found that the introduction of heterogeneous doping Ag and Zn atoms will induce a gradient adsorption energy on MDCSs, and such gradient deposition sites can reduce the diffusion barriers and accelerate the diffusion rates of Li+ ions dynamically. By maneuvering the Li+ ions nucleation on MDCSs, a dendrite-free lithium metal anode can be achieved without the use of porous matrixes and complex synthesis process, which can be attributed to suppress the uncontrollable lithium dendrites for realizing the high-efficiency LMBs.