Nanofibrillar aerogels produced via one-pot chitin nanofibrils liquid exfoliation and self-crosslinking in the DMSO/KOH pseudosolvent system for high-performance lithium-ion batteries

Abstract

Herein, we demonstrate a facile and effective method to construct chitin nanofibrils (ChNFs) aerogels from the DMSO/KOH pseudosolvent systems, which overcome high cost, complicated processes and energy-consumption of traditional procedures. Pseudosolvent treatment allows chitin to fully swell, leading to the delamination of closely packed ChNFs bundles into long and thin nanofibrils and thereby easy formation of strong and entangled nanofibrils networks. The ChNFs aerogels prepared by removing the pseudosolvent possess unique nanofibrous networks with tortuous pore channels, excellent mechanical flexibility and shapeability, good thermal stability as raw chitin, high specific surface area up to 274.9 m2/g and low densities on the order of 10 mg/cm3. This combination offers an opportunity of applying chitin aerogels as distinct biobased separators for lithium-ion batteries (LIBs). Compared with commercial Celgard separator, our chitin separators with higher electrolyte absorption (3278%) and ionic conductivity (1.77 mS/cm−1 at 30 °C) endow LIBs with better rate performance (92.2 mAh/g at 20C) and cycle life (98.2% after 500 cycles). This work provides a sustainable one-pot liquid exfoliation and self-crosslinking of chitin nanofibrils in the pseudosolvent system, which can impart high porosity, low density, large specific surface area and shapeability to chitin, promoting the high-value utilization of agricultural waste chitin.