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Zinc metal, with its high theoretical capacity and low cost, stands out as a promising anode material for affordable high energy-density storage technologies in rechargeable batteries. However, obtaining a high level of reversibility in zinc electrodeposition, which is pivotal for the success of rechargeable zinc-metal-based batteries, remains a significant challenge. A critical factor in this regard is the physicochemical characteristics of the electrolyte solution. Previous studies have indicated that adjusting the electrolyte solutions' composition with additives or co-solvents, along with fine-tuning concentrations and pH levels, can enhance the reversibility and kinetics of Zn deposition/stripping. However, the precise impact of Zn salts counter anions in the electrolyte solutions on these processes is not fully understood yet. Aiming to focus on the key fundamental aspects related to the electrolytes' influences on the Zn electroplating, we delve into the impact of anions on this process. Using advanced in situ and ex situ analytical methods, we reveal the role of the anions in the electrolyte solutions in zinc deposition/dissolution processes. Computational simulations shed light on the electrolytes' solvation structure, establishing a clear relationship between deposition behavior and the molecular variations specific to the different anions. These findings pave the way for new design principles aimed at optimizing the composition of electrolyte solutions for zinc metal batteries, potentially enhancing their performance and efficiency. [ABSTRACT FROM AUTHOR]

Considerable efforts have been invested in replacing standard metallic Zn anodes with diverse conductive substrates in pursuit of higher energy density, durability, and cost-effectiveness in aqueous Zn-based batteries. Despite substantial progress in the development of anode-free Zn systems, there is still a major gap in our fundamental knowledge of how the physicochemical parameters of the substrate (current collector) impact the efficiency of the reversible Zn electrodeposition process. Of particular interest are the interactions between the Zn cations, the accompanied water molecules, and the foreign substrates. As both Zn deposition and hydrogen evolution processes occur at similar potential ranges, the performance of the anode-free cells will be dictated by the catalytic nature of the electrified substrates and the chemistry of their passivation. In this study, we conduct thorough examinations of four prominent current collectors: copper, nickel, titanium, and graphite foils. Using a systematic approach that includes electrochemical investigations supplemented by refined X-ray diffraction analysis and in situ techniques such as online electrochemical mass spectrometry (OEMS) and electrochemical quartz crystal microbalance with dissipation monitoring (EQCM-D), we uncover the critical role of these current collectors in the reversible Zn electroplating process. According to our findings, graphitic foils provide significantly more efficient electrodeposition of Zn in mildly acidic electrolyte solutions. [ABSTRACT FROM AUTHOR]

Nanoparticle-imprinted matrices (NAIMs) are an innovative approach for the efficient and selective recognition of nanoparticles (NPs). The NAIM system comprises the preparation of thin films in which NPs are embedded as a template. The removal of the template forms nanometric voids, which are subsequently used for the selective reuptake of NPs identical to those imprinted. The recognition ability depends on several parameters such as the geometrical compatibility between the voids and imprinted NPs, the thickness of the matrix, and the supramolecular interactions between the matrix and the NP capping agents. Herein, we studied carefully the NP–matrix interactions in three NAIM systems, which were prepared by imprinting identical-sized AuNPs, bearing different carboxylic acid-functionalized thiols as capping agents, in a carboxylic acid-functionalized matrix. This experimental setup has enabled us to meticulously examine the selectivity of the NAIM systems driven by matrix–shell interactions. The three studied NAIM systems have shown high and selective reuptake ability once exposed to solutions of NPs stabilized with the same capping agent used for the imprinting process. In particular, the reuptake percentage of the originally imprinted AuNPs ranges from 50 to 80%, whereas the reuptake of AuNPs bearing different carboxylic capping agents than those imprinted was substantially lower (1–11%). Surface-sensitive polarization-modulation infrared reflection-absorption spectroscopy was utilized to correlate the selectivity of the NAIM systems and hydrogen bonding detected between the capping agents and the matrix. This study paves the way for the rational design of NAIM systems, which can be tuned according to the desired shell–matrix interactions and eventually applied in sensing and separation technologies. [ABSTRACT FROM AUTHOR]