Tetraphenylporphyrin‐based Chelating Ligand Additive as a Molecular Sieving Interfacial Barrier toward Durable Aqueous Zinc Metal Batteries

Abstract

The sustained water consumption and uncontrollable dendrite growth strongly hamper the practical applications of rechargeable zinc (Zn) metal batteries (ZMBs). Herein, for the first time, we demonstrate that trace amount of chelate ligand additive can serve as a “molecular sieve‐like” interfacial barrier and achieve highly efficient Zn plating/stripping. As verified by theoretical modeling and experimental investigations, the benzenesulfonic acid groups on the additive molecular not only facilitates its water solubility and selective adsorption on the Zn anode, but also effectively accelerates the de‐solvation kinetics of Zn2+. Meanwhile, the central porphyrin ring on the chelate ligand effectively expels free water molecules from Zn2+ via chemical binding against hydrogen evolution, and reversibly releases the captured Zn2+ to endow a dendrite‐free Zn deposition. By virtue of this non‐consumable additive, high average Zn plating/stripping efficiency of 99.7 % over 2100 cycles together with extended lifespan and suppressed water decomposition in the Zn||MnO2 full battery were achieved, thus opening a new avenue for developing highly durable ZMBs.

Spontaneous Molecule Aggregation for Nearly Single‐Ion Conducting Sol Electrolyte to Advance Aqueous Zinc Metal Batteries: The Case of Tetraphenylporphyrin

“…Here, tetraphenylporphyrin tetrasulfonic acid (TPPS) is introduced into the conventional electrolyte (ZnSO 4 ). Different from the previous works, [9,14,16] we report that TPPS spontaneously self‐assembles into J‐type aggregations (J‐Agg) after aging, leading to a sol electrolyte. The formation of large molecule aggregates further promotes the electrochemical performance of Zn anodes, compared to single molecules.…”

“…Furthermore, the quick diffusion of anions would also promote the related side reactions, e.g. the formation of Zn 4 SO 4 (OH) 6 ⋅ 4H 2 O (ZHS) on the Zn anode [14] . If Zn‐ion transportation is elevated, the cation depletion near the Zn anodes and the dendrite growth on the Zn anodes would be mitigated.…”

More is better: high-entropy electrolyte design in rechargeable batteries

“…Aqueous liquid HEEs have also been applied to the field of multivalent-ion batteries, especially the most promising Zn-ion batteries. [54][55][56][57] Generally, diluted electrolytes with highly polar solvents tend to solvate all ions (as depicted in the bottom left of Fig. 6a).…”

Simultaneously Tailoring Zinc Deposition and Solvation Structure by Electrolyte Additive

“…Currently, numerous efforts have been made to address these challenges of the Zn metal anode, including interface modification, − membrane design, , and electrolyte additives. − Among these approaches, introducing of electrolyte additives has emerged as a promising method for stabilizing the Zn anode due to its simplicity and low manufacturing cost. , The reported strategies for the use of electrolyte additives can be classified as follows: (1) introducing the additives sodium carboxymethyl cellulose (CMC), arginine (Arg), and dopamine (PDA) to induce the uniform deposition of Zn ions via adsorption on the Zn surface; (2) applying the additives Zn­(BF 4 ) 2 , 2-methyl imidazole (Hmim), and ammonium acetate (CH 3 COONH 4 ) to form a solid electrolyte interphase (SEI) layer at the interface, increasing Zn nucleation sites and secluding direct contact with water; (3) using glucose, tetramethylurea (TMU), hexamethylphosphoramide (HMPA), and others to restructure the solvation shell of Zn 2+ and disrupt the solvation network of water molecules to inhibit hydrogen evolution reaction (HER). However, most of these studies have focused on single or a few independent mechanisms and failed to integrate them organically, rendering them less effective against the complementary interaction between Zn dendrites and the side reaction.…”