Electrochemical Performance of Core-Sheath Dip-Coated Lignin Derived Carbon/Wet-Spun Graphene Electrodes for Fiber-Shaped Supercapacitors

One-dimensional graphene fibers(GFs)possess excellent properties,including high electrical conductivity,good physical and chemical stability,high thermal conductivity,flexibility,etc.GFs are ideal electrode materials for fiber-shaped supercapacitors.However,due to the lack of an effective method to manufacture GFs with high specific capacitance,their low energy density hinders their practical application.Herein,we decorated wet-spun graphene oxide fibers(GOFs)by dip-coating them with graphene oxide(GO)solutions containing different contents of lignin to obtain a core-sheath lignin/GO composite fibers.After carbonization and activation,we successfully prepared lignin derived carbon/GF electrodes.The assembled fiber-shaped supercapacitors(FSSCs)exhibit a specific capacitance of 9.98 mF/cm^(2)and an energy density of 0.89μW·h/cm^(2),about 6 times of those of pure GFs(1.57 mF/cm^(2)and 0.14μW·h/cm^(2),respectively),long cycling life and cycling stability.This suggests that the introduction of lignin derived carbon into GFs can effectively increase the specific capacitance and the energy density of FSSCs.

Crystalline porous materials for catalytic conversion of lignin-related substances

The conversion of the biomass into eco-friendly fuels and chemicals has been exten-sively recognized as the essential pathway to achieve the sustainable economy and carbon neutral society.Lignin,as a kind of promising biomass energy,has been certified to produce the high-valued chemicals and fuels.Numerous efforts have been made to develop various catalysts for lignin catalytic conversion.Both metal-organic frameworks(MOFs)and covalent organic frameworks(COFs)belong to very important heterogeneous porous catalysts due to their regular porous struc-tures,high specific surface area,and precisely tailored diversities.In the review,thefirst part focused on the catalytic conversion of lignin,lignin model compounds,and lignin derivatives using the pristine MOFs,functional MOF composites,and MOF-derived materials.The second part summarized the catalytic conversion of lignin model compounds using pristine COFs and functional COF composites.The review here mainly concentrated on the design of the materials,screening of catalytic conditions,and explorations of the corresponded mechanisms.Specifically,(1)we summarized the MOF-and COF-based materials for the effects on the catalytic trans-formation of lignin-related substances;(2)we emphasized the catalytic mechanism of C–C and C–O bonds cleavage together with the structure–activity relationships;(3)we in-depth realized the relationship between the chemical/electronic/structural properties of the MOF-and COF-based catalysts and their catalytic performance for lignin-related substances.Finally,the challenges and future perspectives were also discussed on the catalytic conversion of lignin-related substances by MOF-and COF-based catalysts.