Phase-field Simulation of Lithium Dendrite Growth in Polymer-based Composite Solid-state Electrolytes
Lithium metal is a highly promising anode material due to its high theoretical capacity and low reduction/oxidation potential,and has received extensive attention.However,the formation and growth of lithium dendrites poses the biggest challenge to its commercialization.The use of solid-state e-lectrolyte,instead of liquid electrolyte,has become a potential path to inhibit the growth of lithium den-drites.However,issues such as poor metal-lithium interface contact and low ionic conductivity in solid-state electrolytes persist.Composite solid-state electrolytes,prepared by combining polymers with inor-ganic ceramic electrolytes,have shown effectiveness in inhibiting the growth of lithium dendrites.Al-though these composite solid electrolytes typically have high ionic conductivity,their elastic moduli are low.Currently,the mechanism of dendrite suppression by low-modulus composite solid-state electrolytes,especially low-modulus multiphase composite solid-state electrolytes,remains incompletely clarified.Therefore,this paper considers the mechanical effects of solid electrolytes and builds a mechanical-chemical model using the phase field method.By taking poly(ethylene oxide)(PEO)-based composite-state electro-lyte as an example,the study investigates the influence of composite solid electrolyte modulus on dendrite growth.The results show that the higher the electrolyte modulus,the greater the stress on the lithium metal,leading to a more uniform distribution of lithium ions on the interface between the electrolyte and the lithium anode electrode.The higher stress also tends to cause the plastic deformation of lithium den-drites,thus inhibiting their growth.This research deepens the understanding of the mechanism of inhibi-tion of lithium dendrites by low-modulus multiphase composite solid electrolytes,and provides guidance for the design of composite solid electrolytes.