Conversion of cotton cellulose to ZnO/C anodes for lithium-ion batteries via a sustainable self-assembly process in a green solvent

Abstract

Today, many efforts have been made in biomass for high-value products. In this article, conversion of cotton cellulose to ZnO/C anodes for lithium-ion batteries (LIBs) was achieved via a simultaneously hierarchical ‘bottom-up’ assembly in a sustainable solvent system. Cotton linter was dissolved in a newly developed aqueous NaOH/zinc nitrate solution, which avoided the usage of common toxic organic cellulose solvents. What is more, the zinc salts therein not only facilitated the cellulose dissolution but were also in situ utilized as the precursor to transform into ZnO nanoparticles; thus, no additional reagents or reactions were needed. Simultaneously, cellulose was regenerated from the solution by self-assembly of its macromolecules as fibrous microspheres encapsulating the ZnO. The self-driven assembly of cellulose molecules as the building block in the solution could provide a highly porous structure as the carbon source to ensure the better performance of the anode materials than the regular non-assembled bio-derived substrate, while most importantly, no waste or by-products would be produced during the self-assembly process. The final ZnO/C composites were characterized as a LIB anode, which exhibited stable charging and discharging performance. This work demonstrated a novel process for the biomass conversion via a sustainable and efficient strategy for high-value-added materials.