Rational Designs for Lithium‐Sulfur Batteries with Low Electrolyte/Sulfur Ratio

Abstract

Lithium‐sulfur batteries (LSBs) are considered a promising next‐generation energy storage device owing to their high theoretical energy density. However, their overall performance is limited by several critical issues such as lithium polysulfide (PS) shuttles, low sulfur utilization, and unstable Li metal anodes. Despite recent huge progress, the electrolyte/sulfur ratio (E/S) used is usually very high (≥20 µL mg−1), which greatly reduces the practical energy density of devices. To push forward LSBs from the lab to the industry, considerable attention is devoted to reducing E/S while ensuring the electrochemical performance. To date, however, few reviews have comprehensively elucidated the possible strategies to achieve that purpose. In this review, recent advances in low E/S cathodes and anodes based on the issues resulting from low E/S and the corresponding solutions are summarized. These will be beneficial for a systematic understanding of the rational design ideas and research trends of low E/S LSBs. In particular, three strategies are proposed for cathodes: preventing PS formation/aggregation to avoid inadequate dissolution, designing multifunctional macroporous networks to address incomplete infiltration, and utilizing an imprison strategy to relieve the adsorption dependence on specific surface area. Finally, the challenges and future prospects for low E/S LSBs are discussed.

Strategies towards High Performance Lithium‐Sulfur Batteries

“…However, using a low E/S ratio reduces the LiPSs redox mediator formation, eventually leading to sluggish redox kinetics, poor active materials accessibility, large polarization, and poor reversibility of the LSB [112] . Since concerns of E/S are being recognized by researchers, several strategies have been developed for the practical application of LSBs [113] . In this regard, Manthiram's group reported a LSBs configured sulfur cathode with a high sulfur loading (57.6 mg cm −2 ) and low E/S ratios (6.0–4.2 μL mg −1 ) of 1.85 M LiTFSI/DOL : DME with 0.2 M LiNO 3 .…”

Customized Structure Design and Functional Mechanism Analysis of Carbon Spheres for Advanced Lithium–Sulfur Batteries

“…metal anode are worthy of our further exploration. [356] In the above review, various CSs and their hybrid materials still show excellent performance in practical conditions and pouch cells.…”

Self‐Supporting Carbon Nanofibers with Ni‐Single‐Atoms and Uniformly Dispersed Ni‐Nanoparticles as Scalable Multifunctional Hosts for High Energy Density Lithium‐Sulfur Batteries

“…[ 4 ] Therefore, designing a host material that allows the fabrication of sulfur cathodes with good‐performance at a high sulfur loading and a low E/S is essential for the future commercialization of LSBs. [ 5 ]…”