Floating catalysis chemical vapor deposition (FCCVD) direct spinning process is an attractive method for fabrication of carbon nanotube fibers (CNTFs). However, the intrinsic structural defects, such as entanglement of the constituent carbon nanotubes (CNTs) and inter-tube gaps within the FCCVD CNTFs, hinder the enhancement of mechanical/electrical properties and the realization of practical applications of CNTFs. Therefore, achieving a comprehensive reassembly of CNTFs with both high alignment and dense packing is particularly crucial. Herein, an efficient reinforcing strategy for FCCVD CNTFs was developed, involving chlorosulfonic acid-assisted wet stretching for CNT realigning and mechanical rolling for densification. To reveal the intrinsic relationship between the microstructure and the mechanical/electrical properties of CNTFs, the microstructure evolution of the CNTFs was characterized by cross-sectional scanning electron microscopy (SEM), wide angle X-ray scattering (WAXS), polarized Raman spectroscopy and Brunauer–Emmett–Teller (BET) analysis. The results demonstrate that this strategy can improve the CNT alignment and eliminate the inter-tube voids in the CNTFs, which will lead to the decrease of mean distance between CNTs and increase of inter-tube contact area, resulting in the enhanced inter-tube van der Waals interactions. These microstructural evolutions are beneficial to the load transfer and electron transport between CNTs, and are the main cause of the significant enhancement of mechanical and electrical properties of the CNTFs. Specifically, the tensile strength, elastic modulus and electrical conductivity of the high-performance CNTFs are 7.67 GPa, 230 GPa and 4.36 × 10⁶ S/m, respectively. It paves the way for further applications of CNTFs in high-end functional composites.

Aqueous zinc battery has been regarded as one of the most promising energy storage systems due to its low cost and environmental benignity. However, the safety concern on Zn anodes caused by uncontrolled Zn dendrite growth in aqueous electrolyte hinders their application. Herein, sucrose with multi-hydroxyl groups has been introduced into aqueous electrolyte to modify Zn²⁺ solvation environment and create a protection layer on Zn anode, thus effectively retarding the growth of zinc dendrites. Atomistic simulations and experiments confirm that sucrose molecules can enter into the solvation sheath of Zn²⁺, and the as-formed unique solvation structure enhances the mobility of Zn²⁺. Such fast Zn²⁺ kinetics in sucrose-modified electrolyte can successfully suppress the dendrite growth. With this sucrose-modified aqueous electrolyte, Zn/Zn symmetric cells present more stable cycle performance than those using pure aqueous electrolyte; Zn/C cells also deliver an impressive higher energy density of 129.7 Wh·kg⁻¹ and improved stability, suggesting a great potential application of sucrose-modified electrolytes for future Zn batteries.