The strategies for achieving a high cationic transport polymer electrolyte (HTPE) have mostly focused on developing single-ion conducting polymer electrolytes, which is far from being practical due to sluggish ion transport. Herein, we present an unprecedented approach on designing an HTPE via in situ copolymerization of regular ionic conducting and single-ion conducting monomers in the presence of a lithium salt. The HTPE, i.e., poly(VEC10-r-LiSTFSI), exhibits a combination of impressive properties, including high cationic transport number (0.73), high ionic conductivity (1.60 mS cm–1), tolerance of high current density (10 mA cm–2), and high anodic stability (5 V). A lithium-metal battery constructed with the developed HTPE retains 70% capacity after 1200 cycles at 1 C, and it also operates in a wide temperature range and with a high mass loading of the cathode. Advanced characterizations and computations reveal that the high t Li+ and high ionic conductivity effectively suppress Li0-dendrite growth by circumventing concentration polarizations that plague most polymer electrolytes.

The lifetime and health of lithium metal batteries are greatly hindered by nonuniform deposition and growth of lithium at the anode–electrolyte interface, which leads to dendrite formation, efficiency loss, and short circuiting. Lithium deposition is influenced by several factors including local current densities, overpotentials, surface heterogeneity, and lithium-ion concentrations. However, due to the embedded, dynamic nature of this interface, it is difficult to observe the complex physics operando. Here, we present a detailed model of the interface that implements Butler–Volmer kinetics to investigate the effects of overpotential and surface heterogeneities on dendrite growth. A high overpotential has been proposed as a contributing factor in increased nucleation and growth of dendrites. Using computational methods, we can isolate the aspects of the complex physics at the interface to gain better insight into how each component affects the overall system. In addition, studies have shown that mechanical modifications to the anode surface, such as micropatterning, are a potential way of controlling deposition and increasing Coulombic efficiency. Micropatterns on the anode surface are explored along with deformations in the solid–electrolyte interface layer to understand their effects on the dendritic growth rates and morphology. The study results show that at higher overpotentials, more dendritic growth and a more branched morphology are present in comparison to low overpotentials, where more uniform and denser growth is observed. In addition, the results suggest that there is a relationship between surface chemistries and anode geometries.

No abstract

No abstract