Polymers in Lithium–Sulfur Batteries

Abstract

Lithium–sulfur batteries (LSBs) hold great promise as one of the next‐generation power supplies for portable electronics and electric vehicles due to their ultrahigh energy density, cost effectiveness, and environmental benignity. However, their practical application has been impeded owing to the electronic insulation of sulfur and its intermediates, serious shuttle effect, large volume variation, and uncontrollable formation of lithium dendrites. Over the past decades, many pioneering strategies have been developed to address these issues via improving electrodes, electrolytes, separators and binders. Remarkably, polymers can be readily applied to all these aspects due to their structural designability, functional versatility, superior chemical stability and processability. Moreover, their lightweight and rich resource characteristics enable the production of LSBs with high‐volume energy density at low cost. Surprisingly, there have been few reviews on development of polymers in LSBs. Herein, breakthroughs and future perspectives of emerging polymers in LSBs are scrutinized. Significant attention is centered on recent implementation of polymers in each component of LSBs with an emphasis on intrinsic mechanisms underlying their specific functions. The review offers a comprehensive overview of state‐of‐the‐art polymers for LSBs, provides in‐depth insights into addressing key challenges, and affords important resources for researchers working on electrochemical energy systems.

Strategies towards High Performance Lithium‐Sulfur Batteries

“…GPEs provide high safety compared to liquid electrolytes, high ionic conductivities, and low interfacial resistance compared to SPEs. [117] GPEs suppress LiPS dissolution, immobilize LiPS in the polymer matrix, and alleviate the shuttle effect.…”

Polymer Electrode Materials for Lithium‐Ion Batteries

“…[168] For example, poly(4,4′-thiodibenzenethiol) (PTBT) electrode with electron-withdrawing phenyl showed a discharge plateau at 2.2 V, while the plateau of PETE with ethyl linker was only 1.6 V. In addition, these main-chain DSPs also performed severe capacity loss. For example, the specific capacity of PTBT decreased by 27.5% after 100 cycles at 0.1 C. [168,169] The capacity decay was attributed to the inefficient reconstruction of -S-S-caused by the sluggish kinetics of small-molecule/oligomer segments. [170][171][172] To alleviate the capacity decay, further optimization of the chemical structure of polymers is required.…”

Tailored porous framework materials for advancing lithium–sulfur batteries

“…To achieve optimized active material utilization and cyclability, the polarity, porosity, and conductivity of the sulfur hosts should be considered as these properties are intimately linked with their ability to confine polysulfides and mobilize charge. Previous studies have utilized porous carbon materials, [5][6][7][8] metal oxides, [9][10][11] and polymers 12,13 as cathode additives. In comparison, metal-organic frameworks (MOFs) offer immense structural and chemical tunability for enabling polysulfide confinement via both physical encapsulation and chemical adsorption.…”