Growth and inhibition of zinc anode dendrites in Zn-air batteries: Model and experiment

Zinc (Zn)-air batteries are widely used in secondary battery research owing to their high theoretical energy density, good electrochemical reversibility, stable discharge performance, and low cost of the anode active material Zn. However, the Zn anode also leads to many challenges, including dendrite growth, deformation, and hydrogen precipitation self-corrosion. In this context, Zn dendrite growth has a greater impact on the cycle lives. In this dissertation, a dendrite growth model for a Zn-air battery was established based on electrochemical phase field theory, and the effects of the charging time, anisotropy strength, and electrolyte temperature on the morphology and growth height of Zn dendrites were studied. A series of experiments was designed with different gradient influencing factors in subsequent experiments to verify the theoretical simulations, including elevated electrolyte temperatures, flowing electrolytes, and pulsed charging. The simulation results show that the growth of Zn dendrites is controlled mainly by diffusion and mass transfer processes, whereas the electrolyte temperature, flow rate, and interfacial energy anisotropy intensity are the main factors. The experimental results show that an optimal electrolyte temperature of 343.15 K, an optimal electrolyte flow rate of 40 mL/min, and an effective pulse charging mode.