Utilizing methacrylated lignin as a sustainable macro-crosslinker for synthesizing innovative PVA/AMPS composites crosslinked hydrogel nanofibers: A potential application for lithium-ion battery separators.

There are significant issues with commercial separators that must be resolved before they can be used in high-energy-density batteries. These problems include low porosity, poor electrolyte wetting, and low mechanical properties. This study presents a facile method for preparing composite crosslinked hydrogel nanofibers of polyvinyl alcohol (PVA) with 2-acrylamide-2-methylpropanesulfonic acid (AMPS) for lithium-ion battery separators by utilizing methacrylated lignin (LMA) as a bio-based crosslinker. Initially, LMA was synthesized by grafting glycidyl methacrylate (GMA) onto lignin via esterification. Subsequently, a crosslinked hydrogel nanofiber membrane (PVA/AMPS-LMA) was electrospun with varying LMA fractions, which were polymerized by combining free radical copolymerization and esterification reactions. The effectiveness of LMA as a crosslinker was assessed against the N, N′-methylene bisacrylamide (MBA). The study showed that using LMA as a crosslinker significantly improved the membrane's properties. The PVA/AMPS-LMA separator displayed superior features such as mechanical strength, thermal stability, porosity, electrolyte uptake, ionic conductivity, and lithium-ion transference number, when compared with PVA/AMPS, PVA, and Celgard separators. Specifically, the PVA/AMPS-LMA separator demonstrated a high mechanical strength of 24.9 MPa, strong thermal stability at 170 °C with no shrinkage, high porosity (84.3 %), and electrolyte uptake (661.4 %). It also exhibited exceptional ionic conductivity (2.75 mS/cm) and a notable lithium-ion transference number (tLi+ = 0.717). In coin batteries, the PVA/AMPS-LMA separator retained over 96 % capacity (142.4 mAh/g) after 200 cycles at 1C. This performance exceeded that of PVA/AMPS, PVA, and Celgard separators, suggesting that PVA/AMPS-LMA separators have the potential to replace their commercial counterparts. [Display omitted] • The PVA/AMPS-LAM separators made by electrospinning-copolymerization process. • The effect of the LMA on the separator's structure and properties was studied. • PVA/AMPS-LAM showed high-porosity, thermal-stability, and mechanical properties. • PVA/AMPS-LAM had highly electrolyte uptake, ionic conductivity, and ion transfers. • PVA/AMPS-LAM separators displayed outstanding electrochemical performance. [ABSTRACT FROM AUTHOR]