Electrospun Poly(vinyl Alcohol)/Chitin Nanofiber Membrane as a Sustainable Lithium-Ion Battery Separator

Commercial battery separators are made of polyolefin polymers due to their desired mechanical strength and chemical stability. However, these materials are not biodegradable and are challenging to recycle. Considering the environmental issues from polyolefins, biodegradable polymers can be developed as separators to reduce the potential waste from polyolefin separators. In this work, we investigated the potential of poly(vinyl alcohol)/chitin nanofiber (PVA/CHNF) nanofiber as a sustainable lithium-ion battery separator, which was successfully fabricated via the electrospinning and cross-linking method. The PVA/CHNF separator is biodegradable and has an ionic conductivity (1.41 mS cm^-1), desirable porosity (86%), good thermal stability (1.4% shrinkage upon heating at 90 °C for 1 h), as well as high electrolyte uptake (388%). The PVA/CHNF separator is also evaluated in the assembled Li//LiFePO₄ cells, showing an improved performance compared to the cell with the commercial separator. It shows a discharge capacity of 142 mAh g^-1, which is stable throughout 120 charge-discharge cycles. Hence, according to these resulting properties, the PVA/CHNF separator shows promise as a sustainable and environmentally friendly lithium-ion battery separator, offering a high-value use of waste chitin materials.