Resolution of the Modulus versus Adhesion Dilemma in Solid Polymer Electrolytes for Rechargeable Lithium Metal Batteries

Abstract

Herein we present a solid electrolyte that adheres to the lithium surface and resists dendrite growth, both of which are needed for the development of high specific energy rechargeable batteries with lithium metal anodes. Nanostructured lamellar block copolymer electrolytes exhibit solid-like properties in the bulk, due to the presence of a randomly oriented granular structure, and liquid-like surface properties due to the formation of perpendicularly oriented lamellae at the lithium-electrolyte interface. The amount of charge that can be passed before short circuit in a symmetric lithium-polymer-lithium cell with nanostructured polystyrene-blockpoly(ethylene oxide) electrolytes is larger than that obtained with homopolymer poly(ethylene oxide) electrolytes by a factor ranging from 11 to 48. Grazing incident small angle X-ray scattering confirms that the microstructure of the block copolymer near the lithium-polymer interface has a perpendicular orientation. This orientation leads to a liquid-like behavior of the polymer at the interface due to the liquid crystalline symmetry of block copolymers. This combination of bulk and surface properties enhances the resistance to dendrites while maintaining electrode-electrolyte contact.

The synergetic effect of lithium polysulfide and lithium nitrate to prevent lithium dendrite growth

“…Among various approaches to overcoming the issues of lithium metal anode, it is recognized that electrolyte selection is one of the most dominant factors for stabilizing the lithium metal surface [14][15][16][17][18][19][20][21][22][23][24][25][26][27] . Although various polymeric and ceramic electrolytes have been demonstrated to suppress lithium dendrite growth [14][15][16][17][18][19][20] , their ionic conductivity, interfacial impedance, mechanical moduli or chemical stability when in contact with metallic lithium were not satisfying and still need further improvement for their implementation.…”

A dendrite-suppressing composite ion conductor from aramid nanofibres

“…The variety of data suggests that improvement of the mechanical properties of the ICM such as E ICM or G ICM could markedly inhibit their growth. 21 Sufficient compressive stress exerted on dendrite tips is expected to inhibit their growth 22,23 .…”

Investigating polypropylene-poly(ethylene oxide)-polypropylene triblock copolymers as solid polymer electrolytes for lithium batteries

“…The molecular weight of the PE block was 0.7 kg/mol, which enabled dissolution of the electrolyte in organic solvent at room temperature. However the mechanical properties of SPEs in this molecular weight regime are well below the target molecular weight required to resist lithium dendrite growth [1,41]. It is obvious that higher molecular weight structural blocks are necessary to obtain robust SPEs with semicrystalline structural blocks.…”