The Zn Deposition Mechanism and Pressure Effects for Aqueous Zn Batteries: A Combined Theoretical and Experimental Study

• Published in: Advanced energy materials 2024-02, Vol.14 (6), p.n/a
• Main Authors: Li, Yuyin, Musgrave, Charles B., Yang, Moon Young, Kim, Minho M., Zhang, Kenan, Tamtaji, Mohsen, Cai, Yuting, Tang, Tsz Wing, Wang, Jun, Yuan, Bin, Goddard, William A., Luo, Zhengtang
• Format: Article
• Language: English
• Subjects: Adatoms; Axial stress; Electric double layer; Electrochemical analysis; electrode‐electrolyte interface; Ion transport; Molecular dynamics; Nucleation; pressure effect; Pressure effects; Quantum mechanics; reactive molecular dynamics simulations; Zn ions batteries
• ISSN: 1614-6832; 1614-6840
• DOI: 10.1002/aenm.202303047

A new reactive force field based on quantum mechanical data for describing formation of the Zn electrode‐electrolyte interface (EEI) chemistry in aqueous zinc‐ion batteries (ZIBs) is developed. This is the first demonstration in which Reactive Molecular Dynamics (RMD) simulation is used to follow the Zn reduction and anode structural evolution at the EEI. It is found that under axial pressure, Zn dendrite formation is inhibited. This is associated with accelerated ion transport and reduction while increasing preference towards horizontal (002) plane growth. Pressure‐induced desolvation of Zn ions within the electric double layer, which promotes faster reduction kinetics is observed. It is found that axial pressure stabilizes adatoms on the (002) plane by decreasing axial atom stress during nucleation and by increasing favorable lateral adatom diffusion, which reduces atomic scale dendrite formation. Finally, these are confirmed results by experimental characterization and electrochemical tests. Zn electroplating process includes ions transportation, reduction, and nucleation. However, the competition among Zn2+ diffusion, reduction kinetics, and crystallographic thermodynamics, remains ambiguous. The powerful computational tool, Reactive Molecular Dynamics simulation, is used to describe the movement, reactions, and nucleation during dynamics at the atomic scale to gain a thorough understanding of the atomistic interface environment and the origin of Zn dendrite formation.