Tremendous efforts have been made toward the development of lithium–sulfur (Li–S) batteries as one of the most reasonable solutions to the rapidly increasing demand for portable electronic devices and electric vehicles, owing to their high cost-efficiency and theoretical energy density. However, the shuttle effect caused by soluble polysulfides is generally considered to be an insurmountable challenge, which can significantly reduce the battery lifecycle and sulfur utilization. Here, we report a lignin nanoparticle-coated Celgard (LC) separator to alleviate this problem. The LC separator enables abundant electron-donating groups and is expected to induce chemical binding of polysulfides to hinder the shuttle effect. When a sulfur-containing commercially available acetylene black (approximately 73.8 wt% sulfur content) was used as the cathode without modification, the Li–S battery with the LC separator presented much enhanced cycling stability over that with the Celgard separator for over 500 cycles at a current density of 1 C. The strategy demonstrated in this study is expected to provide more possibilities for the utilization of low-cost biomass-derived nanomaterials as separators for high-performance Li–S batteries.

High electrolyte wettability, thermal dimensional stability, and tensile strength are prerequisites for implementing separators in practical applications. In this study, we report on the discovery of nanofibril membranes derived from various plant fibers commonly used in the papermaking industry, for low cost and higher performances than the commercially available Celgard2325 in regard to the application of separators for lithium-ion batteries. Nanofibril membranes showed water contact angles as low as 18°, negligible size change at a heating temperature of 160 °C for 120 min, and tensile strength up to 137.6 MPa. The homogenization was found to strongly contribute to these improved performances. These findings suggest that the plant fiber-derived nanofibril membranes are anticipated to be promising candidates as separators for lithium-ion batteries.

Solid acids have been proposed as a hydrolytic agent for wood biomass dissolution. In this work, we presented an environmentally friendly physicochemical treatment to leave behind cellulose, dissolve hemicellulose, and remove lignin from poplar wood. Several pretreatments, such as autohydrolysis and disk refining, were compared to optimize and modify the process. The p-toluenesulfonic acid could extract lignin from wood with a small amount of cellulose degradation. Disk refining with subsequent acid hydrolysis (so-called physicochemical treatment) doubled the delignification efficiency. A comprehensive morphology and overall chemical composition were provided. The crystallinity index (CrI) of treated poplar was increased and the chemical structure was changed after physicochemical treatment. Optical microscopy and scanning electron microscopy analysis demonstrated physicochemical treatment affected the morphology of poplar wood by removing lignin and generating fiberization. In general, this work demonstrated this physicochemical method could be a promising fractionation technology for lignocellulosic biomass due to its advantages, such as good selectivity, in removing lignin while preserving cellulose.