Towards high-performance zinc anode for zinc ion hybrid capacitor: Concurrently tailoring hydrodynamic stability, zinc deposition and solvation structure via electrolyte additive

Strategies for Optimizing the Zn Anode/Electrolyte Interfaces Toward Stable Zn‐Based Batteries

“…Very recently, Zhang's group reported that sodium carboxymethyl cellulose tends to adsorb on the Zn (101) facet, intriguingly achieving a dendrite‐free anode with (101) plane‐dominated Zn deposition behavior. [ 142 ] This is different from the general recognition that the construction of Zn dendrite‐free anodes is more dependent on uniform (002) plane deposition and growth. Additionally, whether the unique orientation induced by additive molecules adsorbed on the Zn surface depends on the additive molecule structure is not clear.…”

“…Considering the high cost of highly and/or superconcentrated electrolytes and the high viscosity of DEEs, introducing electrolyte additives is considered as a low-cost, simple, and reliable approach to modulate the solvation shell of hydrated Zn ions and uniform Zn nucleation and growth, thus stabilizing the electrolyte/anode interfaces. To date, numerous materials have been reported as electrolyte additives, including organic molecules and surfactants (such as ethylene glycol (EG), [134] dimethyl sulfoxide (DMSO), [135] oleic acid, [136] glucose, [137] dimethylformamide (DMF), [138] 𝛽-cyclodextrin, [139] amino acid, [140,141] and carboxymethyl cellulose (CMC) [142] ), water-soluble polymers (such as polyethylene glycol (PEG-200) [143] ), and inorganic salts (such as lanthanum nitrate, [144] Zn(H 2 PO 4 ) 2 , [145] Ce 2 (SO 4 ) 3 , [146] and Zn(BF 4 ) 2 [147] ), and quantum dots (QDs). [148,149] The effects of additives on stabilizing the interfaces are mainly summarized as the following three aspects.…”

“…Second, the additive molecules can be adsorbed on the Zn anode surface, evenly inducing oriented Zn nucleation and deposition. [142,151,152] For example, graphene quantum dots (GQDs) with good hydrophilicity were added into the aqueous electrolyte. [151] Benefitting from the lattice matching, the GQDs can be easily absorbed on the Zn metal surface to manipulate the Zn interfacial reaction (Figure 10d).…”

Zinc-copper dual-ion electrolytes to suppress dendritic growth and increase anode utilization in zinc ion capacitors

“…Upon redox cycling, the electric field concentration on the tips of grains would accelerate the deposition of zinc ions and lead to dendritic protrusions that can break off or even pierce the separator and cause catastrophic short circuits. To mitigate dendritic problems, researchers have added electrolyte additives (16)(17)(18)(19)(20)(21) or ion distributors (22)(23)(24)(25)(26) to redirect zinc concentration for more uniform deposition, but these two methods slowed down the redox kinetics and consequently reduced the power densities. A third method that avoided the tradeoff with kinetics involved promoting zinc deposition on its (002) plane to favor a planar orientation (27)(28)(29)(30).…”

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.…”