Functionalized carbon dots with polydentate ligands for highly stable aqueous zinc ion batteries

Aqueous zinc ion batteries are often adversely affected by the poor stability of zinc metal anodes. Persistent water-induced side reactions and uncontrolled dendrite growth have seriously damaged the long-term service life of aqueous zinc ion batteries. In this paper, it is reported that a zinc sulfide with optimized electron arrangement on the surface of zinc anode is used to modify the zinc anode to achieve long-term cycle stability of zinc anode. The effective active sites of the zinc metal anode surface are first significantly improved by a simple ultrasound-assisted etching strategy, and then the in situ zinc sulfide interface phase further guides the zinc ion deposition behavior on the surface of the zinc metal anode. The zinc sulfide protective layer well regulates the interfacial electric field and the migration of Zn2+, thereby significantly promoting the homogenization of zinc ion flux to achieve dendrite-free deposition. In addition, the aqueous zinc ion full cell assembled based on ZnS@3D-Zn anode achieves better output performance in long-term cycles. In summary, this work sheds light on the importance of reasonable interfacial modification for the development of dendrite-free and stable zinc anode chemistry, which opens up a new path for promoting the development of zinc-based batteries.

Two-dimensional Mg0.2V2O5·nH2O nanobelts derived from V4C3 MXenes for highly stable aqueous zinc ion batteries

Functionalized carbon dots composite cation exchange membranes: Improved electrochemical performance and salt removal efficiency

Nanomaterials with dual-functions integrating diagnostic and therapeutic abilities have attracted the interest in biomedical applications, and low-dimensional carbon dots have shown their potentialities in the field owing to their versatile optical and physicochemical properties. Yet the link between the surface emissive states and their structure and composition is not well understood, and their stability and biocompatibility needs to be further investigated. We have prepared a series of N- and O-doped carbon dots from a commercial commodity with a high surface functionalization, and performed a deep analysis to rationalize the structure-performance indicators that control their fluorescence, cytotoxicity and antioxidant properties. The synthesized carbon dots exhibited broad multiple surface emissive states: a bright blue emission at 430nm governed by electronic transitions involving pyridones and carbonyl moieties, and a greenish emission at 500nm due to transitions involving C-N and C-O groups or trap states. The carbon dots displayed good photostability with negligible photobleaching over continuous excitation during 2h. The carbon dots also displayed good antioxidant activity correlated to the electron storage capacity of the aromatic core and O- and N- groups with proton exchange capacity. The carbon dots showed excellent cytotoxicity on human gingival fibroblast cell lines, and good response in in vitro fluorescence imaging over a wide concentrations range (0.05-1mg/mL), similar to other contrast agents, demonstrating the potential of these N-O- doped carbon dots in imaging applications.

Integrated electrolyte regulation strategy: Trace trifunctional tranexamic acid additive for highly reversible Zn metal anode and stable aqueous zinc ion battery

Aqueous zinc-ion batteries (AZIBs) have emerged as highly promising options for large-scale energy storage systems due to their cost-effectiveness, substantial energy capacity, and improved safety features. However, the Zn anode faces challenges such as self-corrosion and dendrite formation, which limit its practical use in AZIB applications. In this work, a simple blade-coating method was used to successfully coat poly (vinylidene fluoride–hexafluoro propylene) (PVDF-HFP) on the Zn anode. The coated Zn anode (P-Zn) displayed a stable cycling performance (700 h) at 1 mA cm−2 current density in the symmetric cell. In addition, the full cell using MnO2 as the cathode and P-Zn as the anode retained almost full capacity even after 1400 cycles at 2C, far outperforming the full cell using the unmodified Zn anode with only 50% capacity retention after 600 cycles. In situ optical observations of Zn deposition demonstrate that the special organic coating significantly enhances the uniform deposition of Zn2+, thus effectively mitigating corrosion and hydrogen evolution. Density Functional Theory (DFT) calculations show that the PVDF-HFP coating effectively narrows the adsorption energy gap between the P-Zn (002) and (101) planes, leading to the homogeneous deposition of Zn2+ with fewer Zn dendrites. A simple and feasible strategy for designing ultra-stable AZIBs by coating an organic protective layer on the Zn surface is provided by this work.

Synergistic interaction between amphiphilic ion additive groups for stable long-life zinc ion batteries

Hydrothermal synthesis of ammonium vanadate [(NH4)2V7O16•3.6H2O] as a promising zinc-ion cathode: Experimental and theoretical study of its storage

Study on self-healing and corrosion resistance behaviors of functionalized carbon dot-intercalated graphene-based waterborne epoxy coating

Intercalated polyaniline in V2O5 as a unique vanadium oxide bronze cathode for highly stable aqueous zinc ion battery

Aqueous zinc-ion batteries suffer from electrolyte-induced degradation despite their inherent safety advantages. While localized high-concentration electrolytes (LHCEs) mitigate interfacial instability, the excessive cation-anion association elevate ionic transport barriers, resulting in sluggish migration kinetics. Herein, ion-decoupled LHCE (ID-LHCE) are proposed using amphiphilic 2,2,3,3-tetrafluoro-1-propanol (TFP) as anion-affinity diluent. The TFP-mediated anion-diluent matrix (ADM) liberates anion OTF- from Zn2+ solvation sheaths, which maintains Zn2+-enriched nanodomains while significantly reducing ionic transport barriers with an elevated Zn2+ transference number of 0.72. ADM decouples aqueous networks into biphasic H2O-rich/poor nanodomains, establishing a localized environment with attenuated water activity that suppresses hydrogen evolution reaction. Concurrently generated water-deficient interfaces and dehydrated OTF- coordination environment synergistically facilitate the construction of dense gradient heterogeneous SEI: an inner ZnF2-ZnS inorganic layer and an outer oligomer layer, enabling dendrite-free zinc deposition with ultralong cyclability (3,000h at 1mAcm-2) and 99.88% coulombic efficiency. Full cells paired with NaV3O8·1.5H2O cathodes retain 72.5% capacity retention after 2,000 cycles at 0.5Ag-1. Practical viability is demonstrated by the stable operation of high mass loading ampere-hour-level pouch cells (1.04Ah). By correlating molecular interactions, nanoscale phase separation, and macroscopic ion migration, this work establishes a multiscale design paradigm for electrolyte nanostructure.

In this study, bis(salicylidene)ethylenediamine (SALEN) functionalized carbon dot derived from waste banana peels was synthesized using facile hydrothermal technique and the optical biomarker and adsorption properties of the highly fluorescent red nanomaterial studied. The carbon dot and its functionalized counterpart were characterized using FTIR, SEM/EDX and UV-Visible technique. Evaluation of the optical properties of the yellowish brown carbon dot and reddish highly luminescent functionalized carbon dot indicated band gap energy values of 1.85 and 2.04 eV respectively. Extraneous variables such as effect of initial metal ion concentration, pH and contact time were studied in the batch extraction process for the sorption of Cd(II) ions from aqueous solution. The sorption of Cd(II) ion was observed to be highest at pH 5 with 99.3 % removal efficiency. The adsorption isotherm and kinetic models indicated interplay of physisorption and chemisorption processes. The mechanism for the chelation of Cd(II) ions onto the surface of the functionalized carbon dot was mainly governed by inner aphere chelation and ion exchange. Reusability of the material was evaluated using adsorption-desorption experiments. Result of the study indicated the potential of the functionalized carbon dot as (i) semiconductor materials with strong photoluminescence at the visible region which could be used as environmental biomarker and as sensor (ii) effective, efficient and low cost adsorbent for remediating Cd(II) ions contaminated environment.

The development of functional and stable aqueous zinc ion batteries (AZIBs) is critical for application in large‐scale energy storage, owing to their high capacity, low cost, and environmental compatibility. However, the limited reversibility of zinc plating/stripping and the poor cycling stability of the zinc interface in aqueous electrolytes remain major obstacles. Herein, triethylene glycol (TEG) is introduced as a multifunctional additive, whose hydroxyl groups coordinate with Zn2⁺ in the primary solvation sheath while forming a protective layer on the zinc surface. Supported by theoretical modeling and systematic characterizations, TEG is shown to suppress direct H2O interaction with the (002) zinc surface, thereby reducing corrosion, dendrite growth, and hydrogen evolution, while enabling uniform Zn2⁺ deposition. Consequently, symmetric Zn||Zn cells with TEG achieve over 5800 h of cycling at 0.5 mA cm−2, and Zn||NVO full cells exhibit excellent capacity retention. This study aims to motivate a rational and facile strategy for creating stable interface chemistry focused on protecting the metal anode, ultimately improving the practical uses of aqueous batteries.

The problems associated with dendrite growth, hydrogen evolution reaction, and corrosion reaction on the zinc anode surface have hindered the commercial application of zinc-ion batteries (ZIBs). Herein, a crosslinked hydrogel electrolyte (zinc sulfate/polyacrylamide/triethyl phosphate hydrogel, denoted as ZS/TEP/H2O GEL) is designed to stabilize the Zn anode interface and electrolyte, smooth Zn deposition and improve battery cycle life. The ZS/TEP/H2O GEL electrolyte limits water molecule activity through a 3D network, thereby suppressing water-related side reactions and enhancing the stability of the anode. In addition, the TEP additive in ZS/TEP/H2O GEL induces the Zn2+ to deposit preferentially along the (002) crystal plane and enables homogeneous zinc deposition. Ultimately, the Zn//Zn battery assembled with ZS/TEP/H2O GEL can achieve an extremely long-cycle life exceeding 4000 h at 0.2 Ma cm-2. Besides, the Zn//Cu half battery can be plated/stripped stably for more than 1000 cycles at a current density of 1 mA cm-2. The Zn//NVO full battery with ZS/TEP/H2O GEL electrolyte is able to maintain a relatively stable trend at a later stage. This work offers a reference for the exploration of commercialized hydrogel electrolytes with stable zinc anodes to realize long-life ZIBs.

Aqueous zinc ion batteries (AZIBs) have emerged as a promising next‐generation energy storage technology to replace lithium‐ion batteries. Recently, gel polymer electrolytes (GPEs), as a critical component of AZIBs, have garnered significant attention due to their potential to address challenges associated with conventional aqueous electrolytes, such as dendrite growth, corrosion, electrolyte evaporation, and leakage. However, the mechanical properties of hydrogels often remain suboptimal due to inherent limitations. This review focuses on the mechanical requirements that GPEs must meet for practical implementation in AZIBs. Furthermore, it highlights various gel design strategies to achieve superior mechanical performance, including double‐network (DN) gels, topological gels, and other advanced gel network architectures. Promising directions and rational perspectives for future research are also proposed, offering insights into the development of high‐performance GPEs for AZIBs.