The propensity of Zn‐metal anodes to form non‐uniform or dendritic electrodeposits is bound up with the nature of the electrode surface. However, the effect of surface structure on the inherent ...nucleation and deposition of Zn is not yet well understood. Here, the surface structure of a Zn‐metal anode is reconstructed with Sn‐crystal textures via a facile chemical displacement reaction. Compared to the bare Zn, the high‐affinity Zn binding sites of Sn afford lower deposition energy barrier, which promotes deposition kinetics. What is more, a Sn‐textured surface with moderate Zn affinity but high average surface energy ensures a better wettability from the deposits, leading to the lateral growth of Zn crystals. The resultant Sn‐textured Zn‐metal anode exhibits an extremely low voltage hysteresis of 20 mV and achieves a prolonged cycling stability over 500 h cycles without dendrite formation. This work provides new insights into the crystal‐texture‐dependent Zn electrodeposition process and offers direction for direct surface texturing to better stabilize Zn‐metal anodes with improved reversibility.
The surface of a Zn‐metal anode is reconstructed with Sn‐crystal textures via a facile chemical displacement reaction. Such a Sn‐textured surface not only endows a reduced Zn deposition energy barrier but also regulates the lateral growth of Zn crystals, which promotes dendrite‐free electrodeposits and leads to the achievement of an extremely low voltage hysteresis of 20 mV and prolonged cycling performance over 500 h.
Electrocatalysts with low overpotential and high stability are highly demanded in water-splitting system. The efficiency of water-splitting is largely restricted by the oxygen evolution reaction ...(OER). Here, we developed a two-step method to prepare 3D porous material through chemical vapor deposition and electrodeposition combined with the first-principles calculations. Ultrathin α-Co(OH)2 nanosheets grown on the combined substrate of N-doped carbon nanotubes (NCNTs) and nickel foam were fabricated to investigate their electrochemical behaviour. Because of the characteristics of the ultrathin, microporous α-Co(OH)2 and its derivatives, the 3D Co(OH)2@NCNTs@NF exhibits outstanding performance as a bifunctional catalyst for water-splitting. The overpotentials to achieve 10 mA cm−2 current density in 1 M KOH for OER and hydrogen evolution reaction (HER) are 270 mV and 170 mV, respectively. The as-prepared material exhibits superior stability, which generate 10 mA cm−2 current density in overall water-splitting over 600 h without obvious degradation in 1 M KOH at voltage of 1.72 V vs. RHE. The first-principles calculations reveal that the N-doping not only can effectively enhance the interaction between the substrate and active material (CoOOH), but also modulate the electronic structure of CoOOH to speed up the O2 releasing during the OER.
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•3D binder-free catalyst was prepared by CVD and electrodeposition.•The Co(OH)2@NCNTs@NF possesses open porous structure.•The Co(OH)2@NCNTs@NF exhibits high activity and stability in water-splitting.
•Cyclic voltammetry experiments of the additive-free, chloride-based Zn-Mn electrolytic bath were performed to observe its redox behaviour.•Optimum current density range for electrodeposition was ...obtained through potentiostatic studies and Hull cell electrodeposition experiments.•Zn-Mn alloy coatings were obtained through direct and pulsed current electrodeposition and their microstructure, composition and corrosion properties were studied and compared.•Electrochemical impedance spectroscopy was performed on selected DC and PC deposited coatings to study and compare their corrosion mechanisms.•PC deposited coatings at high pulse frequency and low pulse duty cycle showed remarkable improvement in corrosion resistance as compared to DC coatings.
Electrodeposited Zn-Mn alloy coatings are known to provide excellent corrosion resistance to steel due to their ability to form compact corrosion products when exposed to corrosive media. However, obtaining good quality coatings using conventional direct current (DC) electrodeposition from additive free baths is challenging. Pulsed current (PC) deposition has been reported for various Zn based alloy systems to obtain coatings with superior corrosion resistance properties. In this work, Zn-Mn coatings containing up to 9.2 wt. % Mn were electrodeposited on steel from additive-free chloride electrolytes using both DC and PC electrodeposition. Cyclic voltammetry, potentiostatic measurements, Hull cell experiments and SEM-EDS studies indicated good quality DC deposited Zn-Mn coatings in the current density range of 40-60 mA cm−2 with clustered plate morphology at low and cauliflower morphology at higher current densities. PC deposited coatings showed increased Mn contents and improved corrosion rates. The coating deposited at a low duty cycle and a high frequency showed a fine and compact microstructure with the highest Mn content of 9.2 wt. %. XRD studies showed a complete change in phase composition from a monophasic η-Zn-Mn coating with DC to a monophasic ε-Zn-Mn with PC deposition. Electrochemical impedance analysis revealed porous corrosion products in DC coating, whereas the PC coating formed a compact corrosion product which inhibited the dissolution of Zn and Mn, thus providing higher resistance to corrosion. XRD analysis of the samples after corrosion confirmed the presence of zinc hydroxy chloride (ZHC) as a corrosion product. In summary, PC electrodeposited Zn-Mn coatings provided superior corrosion resistance than those obtained through DC.
With advantages such as high theoretical capacity, low cost, and nontoxicity, Zn metal has been widely investigated as an anode for aqueous batteries. However, the problems of dendrite formation and ...sustained corrosion originating from severe interfacial side reactions and uncontrolled Zn electrodeposition in aqueous electrolytes significantly slows down the practical application of Zn metal anodes. To address these issues, herein, an anti‐corrosion elastic constraint (AEC) is introduced that is built with nanosized TiO2 and polyvinylidene fluoride (PVDF) matrix to Zn anode, where the PVDF layer serves as an elastic H2O/O2‐blocking layer and the decorated TiO2 nanoparticles assist uniform Zn electrodeposition. With this corrosion‐inhibition and electrodeposition‐redirection coating, the electrodeposition consistency and thermodynamic stability of the Zn anode are significantly improved, enabling a long‐term stable plating/stripping performance for 2000 h with an ultralow overpotential (<50 mV) and a high average Coulombic efficiency (>99.4%) for 1000 cycles without obvious dendrite formation. Even at a high current density of 8.85 mA cm−2 with limited Zn supply (DODZn = 60%), stable Zn deposition is achieved over 250 h. When coupled with a MnO2 cathode, the AEC‐Zn anode shows a remarkably enhanced full‐cell cycling stability, indicative of high reliability of aqueous Zn batteries for practical application.
An anti‐corrosion elastic constraint is developed to redirect the Zn electrodeposition for aqueous zinc‐ion batteries. With this corrosion‐inhibition and electrodeposition‐redirection coating, the electrodeposition consistency and thermodynamic stability of Zn anodes are significantly improved, enabling a long‐term stable plating/stripping performance for 2000 h with an ultralow overpotential (<50 mV) and a high Coulombic efficiency (>99.4%) for 1000 cycles.
For practical rechargeable aqueous zinc-ion batteries, the long-term cycling stability of the zinc anode remains significantly constrained by its low utilization efficiency and the persistent ...challenge of hydrogen evolution. This study demonstrates the fabrication of ultrathin zinc electrodes with a robust Zn (002) texture while ensuring an adequate supply of zinc metal for use as an anode material. This approach effectively suppresses the tendency of zinc atoms to undergo deposition transformation due to dislocation-induced phenomena. Compared to zinc foils with higher deposition amount, the ultrathin Zn anode exhibits enhanced resistance to dendrite growth and interfacial side reactions. Assembled symmetrical cells based on this ultra-thin Zn anode show a cycle life of 1750 h (1 mAcm−2, 0.5 mAhcm−2), maintaining stable cycling for over 100h even at a high depth of discharge (DOD) of 46.23%. Additionally, the full cell couple with V10O24 exhibits a high initial capacity of 429.6 mAh g−1 and a capacity retention of 75.8% after 1000 cycles.
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•Preventing Zn dendrite formation during cycling by precisely controlling the deposition amount.•Synthesis of ultrathin, strong Zn (002) textured zinc anodes to achieve high utilization, cycling at 46 % DOD for over 100 h.•Elucidates the mechanism underlying the influence of deposition amount on zinc anode performance.
Additives play a pivotal role in achieving high-quality electrodeposited cobalt films for diverse applications in microelectronics. In this work, 1,4-butynediol (BYD) bearing function groups of CC ...and -OH, 1,4-butenediol (BED) featuring C = C and -OH, and glycol (EG) with only -OH were studied to reveal the potential underlying mechanism of unsaturated carbon bonds on cobalt electrodeposition. It is found that BYD inhibits both the cobalt deposition and the formation of adsorbed hydrogen, forming compact cobalt film. Furthermore, the surface and cross-section morphology, grain structure, and resistivity of electrodeposited cobalt are characterized to investigate the effects of alkynol additives. It was observed that BYD induces a change in surface morphology from a mixture of elongated ridges and granular shapes to a flattened granular structure. The texture of the electrodeposited cobalt film transformed from hcp(100) and hcp(101) to hcp(002) with the addition of BYD due to the selective absorption of BYD on specific cobalt orientation. This study not only regulates the grains orientations and properties of electrodeposited cobalt, but also enhances the comprehension of the effect and mechanism of unsaturated carbon bonds on cobalt electrodeposition. These findings provide a theoretical foundation for the selection of additives and their practical applications.
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•A new, unified electrochemical peridynamic model for corrosion and electroplating simulations.•The model describes the anode and cathode processes with a uniform reaction term.•The ...solid–liquid interface reaction is not treated as an effective diffusion process.•Uniform corrosion, pitting corrosion, and plate coating growth are simulated.•The model captures the autonomous evolution of moving solid–liquid interfaces with ease.
In this paper, we introduce a general electrochemical peridynamic formulation to model both corrosion and electroplating processes. Unlike the previous bi-material diffusion-based peridynamic model that combines the chemical reaction and the ion transfer terms into an effective bi-material diffusion term, the new model distinctly separates the reaction term from the effective diffusion term. This treatment allows for convenient calibration of the electrochemical reaction term, and facilitates the accurate reproduction of intricate and comprehensive electrochemical reaction processes, such as pitting corrosion with repassivation and electrodeposition, within a unified framework. The new electrochemical model is validated against the experimental results for uniform corrosion and complex pitting corrosion, and the new model achieves higher accuracy than the bi-material diffusion-based model. Besides the examples shown in this paper, the model can also be applied to other electrochemical processes, such as galvanic corrosion, crevice corrosion, charging and discharging in lithium batteries, etc.
In recent decades, superhydrophobic (SHP) coatings have gained significant attention because of their versatile applications. Superhydrophobic coating is considered as a promising solution to combat ...corrosion and biofouling issues encountered by steel components in various industries. Using a one-step electrodeposition technique, a superhydrophobic coating with strong corrosion resistance and anti-biofouling property was fabricated on carbon steel in this work. With a water contact angle (WCA) of 170.3 ± 4.2° and a sliding angle (SA) of ∼1°, the wettability of the surface was optimized by varying the electrodeposition potential and deposition time. The as-developed superhydrophobic carbon steel surfaces were characterized by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), laser Raman spectroscopy (LRS), Energy dispersive X-ray (EDS) spectroscopy and X-ray diffraction (XRD). Employing field emission scanning electron microscopy (FESEM), the morphology of the superhydrophobic coatings was examined. Potentiodynamic polarization (PDP) technique was used to study the anti-corrosion property of SHP coating and bare sample in 3.5 wt% NaCl solution. The superhydrophobic coating was found to exhibit 99 % corrosion inhibition efficiency. In addition, the biofouling resistance of the coating was evaluated in both gram-negative and gram-positive bacterial cultures and compared with the uncoated sample. Total viability count (TVC) for the SHP coated samples was 5 orders less as compared to the uncoated sample exposed to gram-negative bacterial culture. Similarly, 4 orders reduction in TVC was estimated for the SHP coated sample as compared to the uncoated sample in gram-positive bacterial culture. The impact of superhydrophobic coating on the corrosion performance and biofouling properties of carbon steel was investigated along with the self-cleaning property and robustness of the coating.
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•Electrodeposition of Ni/Ce myristate based coating on carbon steel•Electrodeposition at 50 V for 5 min resulted in 170.3 ± 4.2° WCA and ∼ 1° SA•SHP coating showed chemical stability over a wide pH range.•SHP myristate coating on carbon steel exhibited 99 % corrosion inhibition efficiency.•SHP coating showed biofouling resistance in two different bacterial cultures.
Dynamic windows, which electronically switch between clear and dark states, can play a vital role in energy‐efficient buildings by reducing lighting, heating, and cooling demands. In this manuscript, ...reversible Zn electrodeposition on tin‐doped indium oxide electrodes is studied and a mechanism is proposed that explains the deposition and dissolution processes. This mechanistic understanding enables the construction of 100 cm2 two‐electrode devices that transition from clear (80% transmission at 600 nm) to highly opaque (<0.1% transmission at 600 nm) in less than 20 s. Additionally, the dynamic windows utilize a pH‐neutral electrolyte, which enables them to switch without degradation over the course of four weeks. The high opacity and stability of the Zn‐based devices represent significant improvements over existing switchable thin films based on the reversible electrodeposition of more noble metals such as Bi and Cu.
Reversible Zn electrodeposition on a transparent electrode enables the construction of dynamic windows, which electronically switch between clear and dark states. 100 cm2 devices switch below 0.1% transmission in 20 s. This high opacity is useful for residential settings where privacy is important. pH neutral electrolytes yield windows with superior durability compared to existing devices based on reversible metal electrodeposition.
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•In-situ optical observations during electrochemical deposition of Sb/Sb2O3 composites.•Stripe patterns with Sb- and Sb2O3 regions are formed during Sb/Sb2O3 deposition.•Patterning ...only occurs without active electrolyte convection in vertical arrangement.•Complex coupling of Sb and Sb2O3 deposition can lead to instability of the system.•Development of a natural convection pattern is suggested to induce self-organization.
Sb/Sb2O3 composites are considered promising materials for numerous applications, such as secondary batteries, catalysis and thermoelectrics. Recent research shows that nanostructured Sb/Sb2O3 micro-composites can be obtained straightforward by a single-step electrochemical deposition process. While macroscopically homogenous deposits are obtained in most cases it is shown herein that pattern with Sb and Sb2O3 rich regions emerge under specific conditions. The pattern formation is investigated using electrochemical methods combined with in-situ optical observation and electron microscopy. The origin of pattern formation is proposed to be related to the complex interactions between electrochemical Sb deposition and chemical Sb2O3 precipitation in combination with the emergence of convection patterns in the vicinity of the electrode. These findings contribute to a fundamental understanding in the nascent field of electrochemical metal/oxide co-deposition and can be useful for the rational design of advanced functional composite coatings.
