Ionic receptors to regulate the polysulfide shuttle in lithium-sulfur batteries

Abstract

This disclosure describes a composition including polymers and high dipole moment anion and cation receptors for use in high energy density Li—S batteries and Li-ion sulfur batteries. Methods of making such batteries are also disclosed.

Description

BACKGROUND[0001]The present disclosure relates to power storage and battery devices. More particularly, the present disclosure relates to materials capable of utilizing lithium / sulfur chemistries for use in such power storage and battery devices.[0002]Li-ion batteries (LIBs) are used as power sources in portable electronics and now are being considered to meet other applications, from electric vehicles, to space shuttles, to mitigating global warming issues. However, the capability of energy storage is still a concern due to limited room for developments in conventional electrode materials.[0003]Beyond the limitations of Li-ion batteries towards efficient energy storage, lithium-sulfur (Li—S) systems are promising in the areas of high-energy density, safety, low cost, and long cycle life for electric-based transportation. This is mainly attributed to the high theoretical capacity, wide range of temperature operation, and the low cost and eco-friendliness of sulfur-based cathodes. Ho...

AI Technical Summary

Benefits of technology

The modified separator achieves a three-fold improvement in energy density, stability over hundreds of cycles, and improved safety by minimizing polysulfide diffusion, resulting in high specific capacity and extended cycle life while preventing internal short circuits.

Problems solved by technology

However, the capability of energy storage is still a concern due to limited room for developments in conventional electrode materials.

However, practical applications of Li—S batteries are still hindered due to short cycle life, poor coulombic efficiency, poisoning of the Li-anode, and self-discharge.

These performance limitations generally originate from the insulating nature of sulfur, the shuttling effect of dissolved lithium polysulfide (LiPS) species, and their parasitic reactions with the highly reactive negative electrode.

Though work has been done on cathode frameworks by constructing mesoporous carbon-sulfur composites towards realizing specific capacity, cycle life in the long run still falls short in practical applications due to dissolution of LiPS from cathode.

Poor adsorption (only or mostly van der Waals) of polysulfides and the sulfiphobic nature of carbon surfaces drives this phenomenon.

Progressively, polysulfide (Sn2−) species pass through the separator, causing undesired mass transport of electroactive species and spontaneous reduction of Sn2− at the anode surface, which eventually results in poisoning of the lithium electrode.

Images