Flexible, Self‐Supported Anode for Organic Batteries with a Matched Hierarchical Current Collector System for Boosted Current Density

• Published in: Small (Weinheim an der Bergstrasse, Germany) Germany), 2021-12, Vol.17 (50), p.e2103885-n/a
• Main Authors: Beladi‐Mousavi, Seyyed Mohsen, Klein, Jonas, Ciobanu, Marius, Sadaf, Shamaila, Mahmood, Arsalan Mado, Walder, Lorenz
• Format: Article
• Language: English
• Subjects: Anodes; Charging; Conductors; Electrode materials; Electrodeposition; Electrophoretic deposition; flexible batteries; Graphene; hierarchical current collector; Kinetics; Micrometers; Nanotechnology; organic anodes; organic batteries; reduced graphene oxide; Thickness; viologens
• ISSN: 1613-6810; 1613-6829
• DOI: 10.1002/smll.202103885

The inherent flexibility of redox‐active organic polymers and carbon‐based fillers, combined with flexible current collectors (CCs) is ideal for the fabrication of flexible batteries. Herein, a one‐step electrophoretic deposition of polyviologen (PV)/graphene‐oxide (GO) aqueous composites onto a flexible mesh of 60 µm thick wires, 100 µm apart, is described. Notably, during electrodeposition, GO is transformed into conductive reduced GO (rGO), and nanoscopic pores are formed by self‐assembly allowing charge/discharge of the redox sites over dozens of micrometers. Typically, electrodeposition of PV alone on a flat CC (FCC) is limited by its electrically insulating structure to ≈0.15 mAh cm−2, but the presence of rGO allows thicker active layers without loss in (dis‐)charging kinetics and reaching areal capacities of ≈2 mAh cm−2. Remarkably, when the FCC is replaced by a mesh, the deposition of significantly more anode materials (≈5 mAh cm−2) is possible, while the (dis‐)charging kinetics is considerably improved. It exhibits high capacity retention at an ultrafast rate of 100 C (