A combination of MnO2-decorated graphene aerogel modified separator and I/N codoped graphene aerogel sulfur host to synergistically promote Li–S battery performance

Enhanced ALD Nucleation on Polymeric Separator for Improved Li-S Batteries

Lithium-sulfur (Li-S) batteries, with their superior energy densities, are emerging as promising successors to conventional lithium-ion batteries. However, their widespread adoption is hindered by challenges such as the shuttle effect of polysulfides, which affects discharge capacity and cycling stability. This study explores the transformative potential of atomic layer deposition (ALD) of Al2O3 on commercial PP/PE/PP separators (Celgard), combined with the use of UV ozone exposure to enhance ALD nucleation on the separator surface, to address these challenges. We demonstrate that ALD Al2O3 not only preserves the separator's inherent morphology but also enhances its chemical interactions toward polysulfide, crucial for optimal battery performance. Moreover, batteries with the modified separator exhibit an enhanced specific capacity, reaching up to ∼1150 mAh/g, and a reduced lithium plating overpotential, indicating improved kinetics. Our findings, based on X-ray photoelectron spectroscopy surface characterization and electrochemical evaluations, underscore the significance of ALD-enhanced separators in elevating Li-S battery efficiency by polysulfide adsorption. The research opens up possibilities for high-performance Li-S batteries, suitable for a broad range of applications.

Dual-Confinement Effect of Nanocages@Nanotubes Suppresses Polysulfide Shuttle Effect for High-Performance Lithium-Sulfur Batteries

The shuttle effect of lithium polysulfides (LiPSs) severely hinders the development and commercialization of lithium-sulfur batteries, and the design of high-conductive carbon fiber-host material has become a key solution to suppress the shuttle effect. In this work, a unique Co/CoN-carbon nanocages@TiO2-carbon nanotubes structure (NC@TiO2-CNTs) is constructed using an electrospinning and nitriding process. Lithium-sulfur batteries using NC@TiO2-CNTs as cathode host materials exhibit high sulfur utilization (1527 mAh g-1 at 0.2 C) and can still maintain a discharge capacity of 663 mAh g-1 at a high current density of 5 C, and the capacity loss is only 0.056% per cycle during 500 cycles at 1 C. It is worth noting that even under extreme conditions (sulfur-loading = 90%, surface-loading = 5.0 mg cm-2 (S), and E/S = 6.63 µL mg-1), the lithium-sulfur batteries can still provide a reversible capacity of 4 mAh cm-2. Throughdensity functional theory calculations, it has been found that the Co/CoN heterostructures can adsorb and catalyze LiPSs conversion effectively. Simultaneously, the TiO2 can adsorb LiPSs and transfer Li+ selectively, achieving dual confinement for the shuttle effect of LiPSs (nanocages and nanotubes). The new findings provide a new performance enhancement strategy for the commercialization of lithium-sulfur batteries.

Progress in Research and Application of Graphene Aerogel-A Bibliometric Analysis

In recent years, graphene aerogel (GA) has been widely used as a 3D porous stable network structure material. In order to identify the main research direction of GA, we use the bibliometric method to analyze its hot research fields and applications from the Web of Science database. First, we collected all relevant literature and analyzed its bibliometrics of publication year, country, institution, etc., where we found that China and Chinese Academy of Sciences are the most productive country and institute, respectively. Then, the three hot fields of fabrication, energy storage, and environmental protection are identified and thoroughly discussed. Graphene aerogel composite electrodes have achieved very efficient storage capacity and charge/discharge stability, especially in the field of electrochemical energy storage. Finally, the current challenges and the future development trends are presented in the conclusion. This paper provides a new perspective to explore and promote the related development of GA.