Dendrite‐Suppressing Polymer Materials for Safe Rechargeable Metal Battery Applications: From the Electro‐Chemo‐Mechanical Viewpoint of Macromolecular Design

Abstract

Metal batteries have been emerging as next‐generation battery systems by virtue of ultrahigh theoretical specific capacities and low reduction potentials of metallic anodes. However, significant concerns regarding the uncontrolled metallic dendrite growth accompanied by safety hazards and short lifespan have impeded practical applications of metal batteries. Although a great deal of effort has been pursued to highlight the thermodynamic origin of dendrite growth and a variety of experimental methodologies for dendrite suppression, the roles of polymer materials in suppressing the dendrite growth have been underestimated. This review aims to give a state‐of‐the‐art overview of contemporary dendrite‐suppressing polymer materials from the electro‐chemo‐mechanical viewpoint of macromolecular design, including i) homogeneous distribution of metal ion flux, ii) mechanical blocking of metal dendrites, iii) tailoring polymer structures, and iv) modulating the physical configuration of polymer membranes. Judiciously tailoring electro‐chemo‐mechanical properties of polymer materials provides virtually unlimited opportunities to afford safe and high‐performance metal battery systems by resolving problematic dendrite issues. Transforming these rational design strategies into building dendrite‐suppressing polymer materials and exploiting them towards polymer electrolytes, separators, and coating materials hold the key to realizing safe, dendrite‐free, and long‐lasting metal battery systems.

An acrylate-based quasi-solid polymer electrolyte incorporating a novel dinitrile poly(ethylene glycol) plasticizer for lithium-ion batteries

“…A decrease in Young's modulus from 136 to 20 kPa can also be observed by increasing the plasticizer content, which relates to the greater chain mobility and, therefore, less resistance to deformation [36]. While mechanical blocking implies a strategy for dendrite suppression, a high shear modulus is not essential for cross-linked systems [37]. The introduction of high plasticizer content reduces the effective cross-linking density so that the cross-linked network of ETPTA and PEGDA amounts to only 13.1 wt%, in contrast to 33.8 wt% of bCN-SPE0%.…”

“…The t Li þ for aliphatic dinitriles-plasticized polymer electrolyte membranes with LiTFSI can reach 0.7 with high salt concentrations since the cationic transference number depends on the bulk molar concentration in the salt-rich region [11,61]. A value of 0.28 was calculated for the lithium-ion transference number of bCN-SPE55%, the same as for the commercially available polypropylene separator [37]. The plasticizer bCN-PEG4 has EO units, which facilitate the lithium-ion dissociation but hinder the mobility of lithium ions regarding the transference number.…”

Development and Progression of Polymer Electrolytes for Batteries: Influence of Structure and Chemistry

“…As these polymeric materials have been developed over time, they have demonstrated favourable properties such as low flammability, ease of processing, and electrochemical stability [ 7 , 32 ]. They also offer greater mechanical tolerance to electrode deformation than liquid alternatives [ 33 ]. In addition, their general flexibility offers greater interfacial contact with either electrode compared to other solid-state counterparts [ 34 ].…”

Regulating Na Electrodeposition by Sodiophilic Grafting onto Porosity-Gradient Gel Polymer Electrolytes for Dendrite-Free Sodium Metal Batteries

“…However, comprehensive studies on polymer materials for Na metal batteries, particularly concerning dendrite-suppressing capabilities, are still at a primitive stage. Among various polymeric components, polymer electrolytes play critical roles in all aspects of dendrite evolution because they essentially guide Na + flux by regulating ion transport at the Na metal interface. , Although extensive investigations associated with developing Li dendrite-suppressing polymer electrolytes could aid in devising Na dendrite-suppressing counterparts, , prior expertise collected from developing Li dendrite-suppressing polymer materials is not directly transferable to Na metal battery systems, primarily due to intrinsic differences in Li and Na, particularly regarding ion interactions either with a polymer matrix or electrolyte solvents. , Recently, several strategies have been proposed to alleviate Na dendrite growth by exploiting nanomaterials, − single-ion conducting polymers, , and sodiophilic polymers. − However, relatively little attention has been paid to the ion-regulating capability of polymer electrolytes achieved by surface engineering, and the underlying dendrite-suppressing mechanisms have not been explored.…”