Self-supported lignin-based carbon fibrous aerogels with outstanding rate capability and high oil/seawater separation flux

Abstract

The construction of hardwood kraft lignin (HKL)-based carbon fibrous aerogels (LCAs) for practical application still faces significant challenges. In this work, we proposed to enhance LCAs through the utilization of hydrogen-bonding interactions and π-π interactions. Self-supported LCA/graphene oxide (GO) composites were prepared based on the adhesion of HKL ultrafine fibers and GO, taking advantage of the strong interaction between HKL and GO. The morphology, thermal behavior, chemical structure and crystalline structure of LCA/GO composites were systemically investigated and discussed. Results suggested that HKL ultrafine fibers and GO formed a cohesive whole carbonization due to the influence of hydrogen-bonding and π-π interaction. The prepared LCA/GO composites exhibited outstanding rate capability and high oil/seawater separation flux with their three-dimensional hierarchical channel structures. The specific capacitance of the LCA/GO5.0 electrode was 152 F g−1 at 0.5 A g−1 and 94 F g−1 at 10 A g−1, respectively, while maintaining a retention rate of 113 % after 2000 cycles. The adsorption capacity of the LCA/GO7.5 composite reached up to 55.9 g g−1 and its oil/seawater separation flux was as high as 12,335 L m−2 h−1. The formation strategy, sustainable concept and excellent properties presented in this work will give some inspiration for the preparation of self-supported aerogels as well as their applications in compressible supercapacitors and oil/seawater separation.