In Situ Plasma Polymerization of Self‐Stabilized Polythiophene Enables Dendrite‐Free Lithium Metal Anodes with Ultra‐Long Cycle Life

• Published in: Small (Weinheim an der Bergstrasse, Germany) Vol. 20; no. 31; pp. e2311204 - n/a
• Main Authors: Cao, Shengling, Ning, Jing, He, Xin, Wang, Tianqi, Xu, Cheng, Chen, Manlin, Wang, Kangli, Zhou, Min, Jiang, Kai
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 01.08.2024
• Subjects: Anodes; Anodic protection; artificial polymer modification layer; Chemical bonds; dendrite‐free; Deposition; Lithium; Lithium fluoride; lithium metal anodes; Modulus of elasticity; Molten salt electrolytes; Plasma; plasma polymerization; Polymerization; Polythiophene; Solid electrolytes; Structural stability; plasma polymerization; lithium metal anodes; polythiophene; artificial polymer modification layer; dendrite-free
• ISSN: 1613-6810; 1613-6829; 1613-6829
• DOI: 10.1002/smll.202311204

Constructing a flexible and chemically stable multifunctional layer for the lithium (Li) metal anodes is a highly effective approach to improve the uneven deposition of Li+ and suppress the dendrite growth. Herein, an organic protecting layer of polythiophene is in situ polymerized on the Li metal via plasma polymerization. Compared with the chemically polymerized thiophene (C‐PTh), the plasma polymerized thiophene layer (P‐PTh), with a higher Young's modulus of 8.1 GPa, shows strong structural stability due to the chemical binding of the polythiophene and Li. Moreover, the nucleophilic C─S bond of polythiophene facilitates the decomposition of Li salts in the electrolytes, promoting the formation of LiF‐rich solid electrolyte interface (SEI) layers. The synergetic effect of the rigid LiF as well as the flexible PTh‐Li can effectively regulate the uniform Li deposition and suppress the growth of Li dendrites during the repeated stripping‐plating, enabling the Li anodes with long‐cycling lifespan over 8000 h (1 mA cm−2, 1 mAh cm−2) and 2500 h (10 mA cm−2, 10 mAh cm−2). Since the plasma polymerization is facile (5–20 min) and environmentally friendly (solvent‐free), this work offers a novel and promising strategy for the construction of the forthcoming generation of high‐energy‐density batteries. Polythiophene is in situ polymerized on Li metal by plasma polymerization as a flexible polymer protective layer. The Li anodes modified by the plasma polymerized polythiophene are self‐stabilized on Li metal due to the chemical reaction of Li and the plasma species of thiophene groups, showing much higher structural stability, and the symmetric cells can be stably cycled for 8000 h.