Hydrophobic Molecule Monolayer Brush-Tethered Zinc Anodes for Aqueous Zinc Batteries

Abstract

Aqueous zinc batteries are of great interest as a rechargeable energy storage system, particularly owing to the low cost and high safety of aqueous electrolytes, as well as the high capacity of zinc anodes. Unfortunately, the wide commercialization of aqueous zinc batteries is impeded by the irreversible water reduction and irregular zinc evolution issues on the anode side. Hereby, a hydrophobic and ultrathin polystyrene molecule brush layer is tethered onto the surface of zinc metal anodes to tackle the above limitations. Experimental investigations reveal that the waterproof artificial layer can sustain fast interfacial ionic transportation, minimize hydrogen evolution, and smoothen Zn deposition, thus conferring enhanced electrochemical performance to the as-protected Zn anode in both symmetric Zn//Zn cells and Zn//LiV 3 O 8 full cells.

Multifunctional polyzwitterion ionic liquid coating for long-lifespan and dendrite-free Zn metal anodes

“…As shown in Fig. 4e, compared with the recent reports, 12,13,[53][54][55][56] the cycle life (4500 cycles) and the current density with high capacity (250.12 mA h g À1 ) applied to Zn@P(SBMA-co-BuA) in our work have reached a high level, demonstrating that our strategy is able to meet practical applications such as high current density, high capacity and long life. This benets from the waterblocking P(SBMA-co-BuA) coating preventing the adverse interaction between water and Zn metal, and the zwitterionic coating slowing down the activity of Zn 2+ on the electrode surface, so that Zn 2+ can be deposited uniformly and avoid dendrite growth.…”

Insights on Artificial Interphases of Zn and Electrolyte: Protection Mechanisms, Constructing Techniques, Applicability, and Prospective

“…Owing to its hydrophobic characteristic, an ultrathin polystyrene (PS) molecule brush film with a thickness ≈6.5 nm was tethered on Zn surface, which can effectively insulate water penetration and suppress H 2 evolution. [ 109 ] Due to the space‐confinement effect of the vertically aligned molecule brush, the coated Zn accelerated the ionic transportation at electrolyte/electrode interface, and achieved a short 2D nucleation time (only 0.9 s) for uniform and smooth Zn deposition (Figure 9k). Contributed by the channels in PS ASEI, the homogenized Zn 2+ flux and the constrained ionic transport resulted in a high‐density and uniform nuclei layer between Zn and ASEI shown in Figure 9l.…”

Guiding Principles for the Design of Artificial Interface Layer for Zinc Metal Anode

“…It is important that one end of the molecular brush away from the Zn metal substrate has hydrophobic groups, so the molecular brush interface film can block the infiltration of water molecules to a certain extent. [89] Lee et al described ionic liquid (IL) gels as a waterproof ionic conductive protective layer customized for zinc anodes by ultraviolet (UV) curing, which consists of a hydrophobic ionic liquid solvent (BMPTFSI), a zinc salt (Zn(TFSI) 2 ), and a thiol-ene polymer-compatible skeleton. BMP + cation is hydrophobic in BMPTFSI, which can effectively shield water molecules and inhibit its decomposition.…”

“…The molecular brush was combined with the Zn substrate through the chemical dehydration reaction between the hydroxyl group, and the resulting molecular brush interface layer has the characteristics of single layer and small thickness. It is important that one end of the molecular brush away from the Zn metal substrate has hydrophobic groups, so the molecular brush interface film can block the infiltration of water molecules to a certain extent [89] . Lee et al.…”