Architecting the Microenvironment Skeleton of Active Materials in High‐Capacity Electrodes by Self‐Assembled Nano‐Building Blocks

• Published in: Small (Weinheim an der Bergstrasse, Germany) Germany), 2024-06, Vol.20 (23), p.e2307086-n/a
• Main Authors: Zhu, Zhiwei, Wu, Dichen, Feng, Lanxiang, He, Xuewei, Hu, Ting, Ye, Ang, Fu, Xuewei, Yang, Wei, Wang, Yu
• Format: Article
• Language: English
• Subjects: Active control; active material microenvironment; Bonding strength; Difluorides; Electrodes; Energy storage; high‐energy‐density thick electrodes and batteries; lithium–sulfur; Microstructure; Self-assembly; self‐assembled dry slurry; semi‐dry electrode manufacturing; Slurries; Solvation; Sulfur; Vinylidene
• ISSN: 1613-6810; 1613-6829
• DOI: 10.1002/smll.202307086

In analogy to the cell microenvironment in biology, understanding and controlling the active‐material microenvironment (ME@AM) microstructures in battery electrodes is essential to the successes of energy storage devices. However, this is extremely difficult for especially high‐capacity active materials (AMs) like sulfur, due to the poor controlling on the electrode microstructures. To conquer this challenge, here, a semi‐dry strategy based on self‐assembled nano‐building blocks is reported to construct nest‐like robust ME@AM skeleton in a solvent‐and‐stress‐less way. To do that, poly(vinylidene difluoride) nanoparticle binder is coated onto carbon‐nanofibers (NB@CNF) via the nanostorm technology developed in the lab, to form self‐assembled nano‐building blocks in the dry slurry. After compressed into an electrode prototype, the self‐assembled dry‐slurry is then bonded by in‐situ nanobinder solvation. With this strategy, mechanically strong thick sulfur electrodes are successfully fabricated without cracking and exhibit high capacity and good C‐rate performance even at a high AM loading (25.0 mg cm−2 by 90 wt% in the whole electrode). This study may not only bring a promising solution to dry manufacturing of batteries, but also uncover the ME@AM structuring mechanism with nano‐binder for guiding the design and control on electrode microstructures. To better control the electrode microstructure, especially for high‐capacity sulfur cathodes, a semi‐dry strategy is reported to construct nest‐like robust microenvironment of active material skeleton in a solvent‐and‐stress‐less way. Along with compression and lean solvent dosage, the self‐assembled dry slurry made by nanostorm technology is bonded by in situ nanobinder solvation. Mechanically robust thick sulfur cathode can be prepared and deliver excellent electrochemical performance.