Flexible, Electrically Conductive, Nanostructured, Asymmetric Aerogel Films for Lithium-Sulfur Batteries

Lithium-sulfur batteries are afflicted with capacity fading on account of polysulfide shuttling. A novel cost-effective electrode that can hinder the polysulfide shuttling and realize high active material utilization is highly required. Here, we demonstrate a flexible, electrically conductive, nanostructured, and asymmetric hybrid cathode by integrating a high-aspect-ratio wood nano-cellulose and a low-cost commercial carbon nanotube (similar to$ 0.2 g(-1)) into an entangled aerogel film. The vacuum filtration combined with lyophilization enables the aerogel film with quite different nanofiber/nanotube packing densities and pore structures at its two sides. The cooperative effects of the entangled building blocks and the asymmetric porous structure of the aerogel film stimulate the simultaneous increase of active sulfur loading, enhancing the electrolyte penetration, alleviating dissolution and shuttling of polysulfide ions, and promoting the fast electron transportation. The as-generated cathode exhibited a capacity fading of 0.01% per cycle over 1000 discharge/charge cycles at a 0.5 C rate (1 C = 1675 mA g(-1)). The average Coulombic efficiency reached similar to 99.7%.

Automated summary

A novel hybrid cathode composed of wood nano-cellulose and commercial carbon nanotubes was shown to effectively increase active sulfur loading, enhance electrolyte penetration, alleviate polysulfide ion dissolution and shuttling, and promote fast electron transportation, resulting in excellent cycling stability and high Coulombic efficiency in lithium-sulfur batteries.