Rechargeable Aqueous Zinc-ion Batteries Research Articles

Impacts of distorted local chemical coordination on electrochemical performance in hydrated vanadium pentoxide

Modulating and elevating the operating voltage of a given cathode is a significant challenge to enhance the energy density of secondary batteries without sacrificing power output. The chemical coordination strongly influences the energy levels of d-orbitals of redox cations in cathode materials, which tie to their operating voltage. In contrast to concentrated studies on enhancing the specific capacity, in this study, we choose bi-layered hydrated vanadium pentoxide as the model to modulate the d-orbital energy levels through local chemical coordination manipulation, achieving a higher operating voltage in rechargeable aqueous zinc ion batteries. Here we show that, by employing X-ray absorption spectroscopy (XAS) and pair distribution function (PDF) techniques, we can analyze the distortion of [VO6] octahedra and extract chemical bond information, deciphering the correlation between the chemical coordination and operating voltage in cathode materials. The fundamentals could guide the designing and developing RAZIBs with higher energy and power density.

A High-Voltage n-type Organic Cathode Materials Enabled by Tetraalkylammonium Complexing Agents for Aqueous Zinc-Ion Batteries.

Tetrabutylammonium (TBA) salt of hexacyano-substituted cyclopropane dianion (Cp(CN)6 2 -) is prepared through a facile two-step synthetic protocol from commercially available materials and fully characterized as a high-voltage n-type organic cathode in rechargeable aqueous zinc-ion batteries (AZIBs). The addition of tetrabutylammonium triflate (TBAOTf)to the electrolyte mitigates dissolution issues, leading to enhanced cycling stability. Remarkably, the Cp(CN)6 2 - cathode demonstrates a high discharge voltage of 1.43V in AZIBs and retains 85% of its capacity after 1000 cycles at a high loading of 10mg cm- 2 and a cycling rate of 10C. These results, combined with spectroscopic analyses, elucidate a reversible two-electron redox process of Cp(CN)6 2 - facilitated by the insertion/de-insertion of TBA cation. These findings underscore the potential of Cp(CN)6 2 - as a conversion-based n-type cathode in energy storage applications.

Effective CuO/Cu7S4 nanospheres heterostructures for advanced “rocking-chair” zinc-ion battery

Rechargeable aqueous zinc-ion batteries (ZIBs) have attracted considerable attention for energy storage owing to their environmental friendliness and high safety. However, the adverse side reactions and unsatisfactory cycle life brought by Zn-metal anodes limit their large applications. Herein, CuO/Cu7S4 (CSO) heterostructured hollow nanospheres is proposed as an attractive conversion-type Zn-metal-free anode for “rocking-chair” ZIBs. The CSO/graphite self-supporting electrode delivers a high capacity of 271 mAh/g at current density of 0.1 A/g and a superior cyclic stability of 1200 cycles. Based on the excellent electrochemical performance of CSO/graphite electrode, we have constructed a self-powered pressure sensor integrated system using the “rocking-chair” zinc ion battery as the power source, demonstrating significant practicality. This work provides a high-performance conversion type anode material for aqueous multivalent metal ion batteries.

Unravelling the performance of lead-free perovskite cathodes for rechargeable aqueous zinc-ion batteries

The quest for efficient and sustainable energy storage solutions has led to the emergence of zinc-ion batteries (ZIBs) as a promising candidate, offering numerous advantages in terms of cost-effectiveness, safety, and performance. The key to commercialising ZIBs lies in developing cathode materials that offer high specific capacity and prolonged cycle performance. The present study demonstrates the capability of environmentally friendly, lead-free inorganic perovskites for high-rate rechargeable aqueous zinc-ion batteries with enhanced stability and excellent rate performance. The battery exhibits a high specific capacity of 220 mAh/g at a current density of 1000 mA/g and a quite stable capacity of 50 mAh/g and a good cycling stability of 20000 cycles at a very high rate of 20 A/g. The caesium bismuth iodide perovskite emerges as a promising candidate for cathode material in Zn-ion batteries, exhibiting high specific capacity and superior rate cyclability. Furthermore, incorporation of Ag in CsBi3I10 is found to enhance the specific capacity and exhibits superior cycling stability. This study marks a significant advancement in the utilisation of perovskite materials as new cathodes for high-rate ZIBs.

Multifunctional Self-Assembled Bio-Interfacial Layers for High-Performance Zinc Metal Anodes.

Rechargeable aqueous zinc-ion (Zn-ion) batteries are widely regarded as important candidates for next-generation energy storage systems for low-cost renewable energy storage. However, the development of Zn-ion batteries is currently facing significant challenges due to uncontrollable Zn dendrite growth and severe parasitic reactions on Zn metal anodes. Herein, we report an effective strategy to improve the performance of aqueous Zn-ion batteries by leveraging the self-assembly of bovine serum albumin (BSA) into a bilayer configuration on Zn metal anodes. BSA's hydrophilic and hydrophobic fragments form unique and intelligent ion channels, which regulate the migration of Zn ions and facilitate their desolvation process, significantly diminishing parasitic reactions on Zn anodes and leading to a uniform Zn deposition along the Zn (002) plane. Notably, the Zn||Zn symmetric cell with BSA as the electrolyte additive demonstrated a stable cycling performance for up to 2400 hours at a high current density of 10 mA cm-2. This work demonstrates the pivotal role of self-assembled protein bilayer structures in improving the durability of Zn anodes in aqueous Zn-ion batteries.

Toward the Rechargeable Aqueous Zinc Ion Batteries with Improved Overall Performance: Electrolyte with Surface Adsorptive Additive.

Aqueous zinc-ion batteries (AZIBs) with slightly acidic electrolytes process advantages such as high safety, competitive cost, and satisfactory electrochemical performance. However, the failure behaviors of both electrodes, regarding zinc dendrite growth, interfacial parasitic reactions, and the collapse of cathode materials hinder the practical application of ZIBs. To alleviate the issues of both anode and cathode at the same time, D-xylose (DX) is introduced to the electrolyte as a multifunctional additive. As a result, the side reaction of the anode is suppressed and the metallic deposition behavior is regulated due to the hydrogen bonding network reconstruction and preferential surface adsorption of DX; for the MnO2 cathode, the DX adsorption can help the interfacial charge transfer and increase the reactive sites. Benefiting from these merits, DX-optimized Zn//Zn battery displays reveal a prolonged lifespan of 6912h and an ultra-high cumulative capacity of 17.28Ahcm-2 at 5mAcm-2. With the function of water reactivity suppression, the Coulombic efficiency reaches 99.91% at 2mAcm-2; the Zn||MnO2 full batteries exhibit excellent cyclability over 2000 cycles at 5C with an increased capacity of 118.9mAhg-1, indicating the dual functions to both of the electrodes for AZIBs.

Cu2+ intercalation bolstering the rate capability of δ-MnO2 cathode for aqueous zinc-ion battery

Cost-effective manganese dioxide (MnO2) promises the economical advantage of rechargeable aqueous zinc-ion batteries (ZIBs) but suffers its low electrical conductivity, the irreversibility of structural transformations during electrochemical reactions, and the slow kinetics of the reactions. This study employs a one-step co-precipitation technique to synthesize Cu2+ intercalated δ-MnO2 nanoflower. The intercalation of Cu2+ not only enlarges the interlayer spacing through the interaction with water molecules, but also strengthens the interlayer structure with Cu2+ as the pillars, improves the ionic conductivity, and enhances the rate capability of δ-MnO2. It is attributed to the co-insertion/extraction mechanism of Zn2+/H+. Therefore, the Cu2+ intercalation δ-MnO2 developed for ZIBs demonstrates a high specific capacity (300 mAh g−1 at 0.1 A g−1), long cycling stability (179 mAh g−1 until 2000 cycles at 1 A g−1 89.9 % capacity retention), and superior rate capability (195 mAh g−1 at 1 A g−1). Meanwhile, the flexible ZIBs assembled with this cathode material have wider commercial applicability.

Reconfiguring Zn2+ Solvation Network and Interfacial Chemistry of Zn Metal Anode with Molecular Engineered Crown Ether Additive

AbstractThe practical deployment of rechargeable aqueous zinc‐ion batteries (RAZBs) in the scaled power system suffers from unregulated Zn dendrite growth as well as parasitic reactions at the zinc foil/aqueous electrolyte interface, leading to insufficient zinc utilization and severe electrode corrosion. Herein, a novel crown ether additive is developed, with tailored molecular engineering, to stepwise regulate the Zn2+ solvation network and interfacial chemistry of Zn metal anode. The designed crown ether (C5SeCN), featuring zincophilic cyano group and hydrophobic selenium, efficiently reconstructs the solvation sheath of Zn ions at the 0.3 wt.% dose amount. Additionally, the ozone plasma treatment tethers the O2‐ groups onto the thin‐layer zinc foil, which thus binds Se atoms of the C5SeCN to the Zn anode. The Zn||Zn symmetric cells exhibit a lifespan of over 4500 h at 1 mA cm−2 and high current density endurance of up to 10 mA cm−2. Moreover, the 2 mAh cm−2 Zn||V2O5 full cell model, at the low N/P ratio of 2.8 with a lean electrolyte (E/C ratio = 10 µL mAh−1), enables robust cycling endurance at 2 A g⁻¹ for 300 cycles. This study unravels the interfacial design rationales for maximizing zinc utilization and highlights the commercial potential of crown ether additives for RAZBs development.

Efficient structural and compositional modulation of vanadium oxides for high-areal-capacity zinc-ion batteries

Although rechargeable aqueous zinc-ion batteries (RAZIBs) have been revitalized as competitive candidates for large-scale energy storage, the development of this technology is stalled by the underutilization of cathode materials due to sluggish reaction kinetics, resulting in low areal capacities that cannot meet the practical requirements. Herein, this study reveals a simple, efficient, and low-energy synthetic route to effectively convert relatively inactive α-V2O5 (131 mAh g−1 at 0.1 A g−1) into highly active MxV8O20·nH2O (MVO, M = Li, Na, and K) by liquid-phase dissolution-recrystallization reaction and chemical preintercalation under low-temperature conditions. Particularly, NaVO presents the most expansive diffusion channel, the highest specific surface area, and the smallest band gap, allowing faster electron/ion transport kinetics and better material utilization. With these features, NaVO accommodates electrolyte Zn2+ and H+ with good reversibility, showing high capacity (383 mAh g−1 at 0.1 A g−1) and rate-performance (207 mAh g−1 at 8 A g−1). More importantly, high-areal-capacity of 3.2 mAh cm−2 and remarkable cycle stability over 1500 cycles can be achieved from free-standing high-mass-loading electrode (∼14 mg cm−2) made of NaVO and multi-walled carbon nanotubes (MWCNTs). This work enriches the synthetic methods for obtaining high-performance vanadium-based host materials with practical areal capacity and cycle stability.

Two-dimensional heterostructure of MXene-derived V2O5·H2O and graphene with enhanced Zn-ion storage capability

Aqueous rechargeable zinc-ion batteries (ZIBs) are promising candidates for gird-scale energy storage with economic and environmental advantages. Layered hydrated vanadium oxides with multivalent and “lubricating” effect receive much attention in ZIBs. However, the application of them is suffering from the poor intrinsic conductivity and the unstable structure. Herein, a unique 2D/2D heterostructure of δ-V2O5·H2O nanobelts (VO) and reduced graphene oxide (rGO) is designed as cathode for ZIBs (denoted as VOG). The stronger interface coupling and the shorter ion transport pathways impart the VOG electrode impressive stability and fast ions diffusion kinetics. Specifically, the VOG cathode delivers a superior capacity of 342 mAh g−1 at 1 A g−1 and a remarkable rate capability of 280 mAh g−1 at a quite high rate of 10 A g−1. The energy storage mechanism involved is investigated by systematical characterizations. The exploration of such 2D/2D heterostructure materials with strong synergy sheds light on the rational design of high performanced AZIBs.

Cobalt-doped copper sulfide nanocomposite integrated with graphene oxide as a high-performance conversion anode for aqueous zinc-ion batteries

Rechargeable aqueous zinc-ion batteries (ZIBs) encounter substantial obstacles arising from the inherent dilemmas of dendrite growth, hydrogen gas evolution, and corrosion affiliated with zinc metal anodes, thereby highlighting the necessity for researching conversion anode materials as a promising pathway forward. Copper sulfide (CuS) has been demonstrated as a promising conversion anode material for ZIBs due to its notable electrochemical performance, while challenges persist regarding the Coulombic interactions between Zn2+ and host anions, coupled with the material’s fundamental conductivity that remains less than fully satisfactory. To address the above issues, we have designed and synthesized a nanostructured composite of cobalt doped CuS integrated in graphene oxide frames (GO/Co-CuS) as anode for ZIBs. The cobalt doping serves to alleviate Coulomb interaction (Coulomb attraction) between Zn2+ and host anions, thereby enhancing the kinetics of Zn2+ diffusion. Furthermore, the incorporation of GO framework improves the electrical conductivity of the material and mitigates volume expansion during the reaction process. The synergistic effect engendered by the combination of cobalt doping and the incorporation of a GO framework results in the remarkable electrochemical performance exhibited by GO/Co-CuS. The GO/Co-CuS composite nanostructure exhibited commendable rate capability and cycling stability. Specifically, it exhibits remarkable rate capability, delivering 296 mAh g−1 at 1 A/g and 168 mAh g−1 at 10 A/g. Furthermore, after 1000 cycles at a high current density of 10 A/g, it maintains a capacity of 166 mAh g−1, demonstrating exceptional cycling stability. Additionally, the full-cell configuration of GO/Co-CuS//MnO2@CNTs, when cycled 241 times at 2 A/g, retains a capacity of 79 mAh g−1, thereby confirming the practical efficacy of the GO/Co-CuS nanocomposite as an efficient conversion anode for ZIBs.

Electrochemical constructing versatile ZnAl-LDH artificial interface layer coated (002)-textured Zn for highly reversible zinc anodes

Rechargeable aqueous zinc-ion batteries (AZIBs), renowned for their high safety, cost-effectiveness, and high energy density, are regarded as an alternative for large-scale energy storage. However, persistent challenges remain in achieving highly reversible AZIBs, primarily centered around the notorious issues associated with the Zn anode. Here, a zincophilic Zn-Al layered double hydroxide (ZnAl-LDH) artificial interface layer coated highly (002)-textured Zn metal anode (SZ/LDH@Zn) with an integrated design are successively constructed by electrochemical methods. Comprehensive characterizations and theoretical calculations reveal that the preferred (002)-textured Zn couping with the zincophilic ZnAl-LDH coating layer not only can effectively regulate the interfacial electric field and Zn2+ flux distribution, guiding a uniform and horizontal Zn2+ deposition but also provide inherent Zn2+ diffusion channels, accelerating its interfacial transport kinetics. Moreover, the ZnAl-LDH layer with good chemical stability acted as a robust physical barrier, impeding direct contact between the electrolyte and Zn anode, thus curbing interfacial side reactions. As a result, the SZ/LDH@Zn||SZ/LDH@Zn symmetric cell delivers unprecedented cycling stability of 5500 h (about 230 days) at 1 mA cm−2, 1 mA h cm−2. The SZ/LDH@Zn||Cu asymmetric cell achieves superior reversibility with a high average Coulombic efficiency of 99.85 % over 3800 cycles. More significantly, the SZ/LDH@Zn||NaV3O8·xH2O full cell with a low N/P ratio (3.62) exhibits an impressive areal capacity of 5.36 mA h cm−2 and reliable operation over 1500 cycles. This work offers a facile and controllable electrochemical coupling strategy to build a highly stable Zn metal anode.

Impact of morphology and crystalline structure over the Zn2+ ions storage in two-step solvothermal derived VO2

Aqueous rechargeable zinc ion batteries (ARZIBs) represent a cheaper and more environmentally friendly alternative to lithium-ion batteries (LIBs) in energy storage systems. Vanadium oxide is one of the most attractive materials to be used as a cathode in ARZIBs because it has multiple oxidation states that grant high specific capacity. This work employed an alternative synthetic route to obtain VO2 with varied morphology and structural properties utilizing vanadyl acetylacetonate as a precursor by tuning the temperature during two-step solvothermal/hydrothermal treatment. When highly crystalline VO2 (B) with rod morphology is obtained, the electrode exhibits the best electrochemical response, with the most significant contribution of surface-confined redox processes to the charge stored. The ARZIB assembled with VO2 rod showed an initial capacity of up to ∼300 mA h g−1 (2.4 mA h cm−2) at 0.1 A g−1, delivering a specific energy of up to 168 W h kg−1 at a specific power of 65 W kg−1. It exhibits outstanding stability after 2000 GCD cycles at 2.5 A g−1. Ex-situ structural and spectroscopic characterization showed that Zn2+ storage causes an expansion and contraction of the lattice without evidence of crystalline phase transformations.

Performances of MnO2 and SnO2 Coated MnO2 as Cathode Materials for Aqueous Rechargeable Zinc-ion Batteries

In this study, the micro-emulsion method was used to create the manganese-based cathode materials MnO2 and MnO2@SnO2. For the use as cathode materials in rechargeable zinc-ion batteries, MnO2 and SnO2 coated MnO2@SnO2 were synthesized. FT-IR, Powder X-ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM), Energy Dispersive X-ray Spectroscopy (EDS), and UV-visible Spectroscopy were used to characterize the as-prepared materials. Electrochemical impedance spectroscopy (EIS), battery charge-discharge (BCD), and cyclic voltammetry (CV) techniques were used to investigate the electrochemical properties of the prepared cathode materials for aqueous rechargeable zinc-ion batteries (ARZIBs). The CV profiles were measured in the potential range of 2.1-1.0 V at a scan rate of 20 mV/s. A pair of redox peaks can be seen in the cycle of CV curves. Charge/discharge cycles of SnO2 coated MnO2@SnO2 electrodes are higher than those of pristine MnO2. SnO2 coated MnO2@SnO2 electrodes have better initial charge/discharge capacities than pristine MnO2 electrodes, which is a factor to take into account. In the first cycle, SnO2 coated MnO2@SnO2 electrode has a 26% higher charge capacity than the bare MnO2 electrode. The SnO2 coating on MnO2 may be the cause of the enhanced charge and discharge capabilities of MnO2@SnO2. J. of Sci. and Tech. Res. 5(1): 83-92, 2023

Understanding the hydrogen and halogen bonds of ionic liquids in regulating ion solvation and dynamic behaviors of aqueous zinc electrolytes

Despite their low cost and intrinsic safety, aqueous rechargeable zinc-ion batteries suffer from rapid performance deterioration originating from parasitic reactions and inhomogeneous deposition on the Zn anode. Halogen bonds share similarities with hydrogen bonds, yet their unique directionality, strength tunability, and hydrophobicity provide a promising approach for enhancing the reversibility of Zn anodes. Herein, a systematic comparison of ionic liquids with different anions, acetate (Ac−) and chloride (Cl−), is performed to explore the non-covalent interactions in regulating ion solvation and dynamic behaviors of electrolytes. Different from the Ac− possessing a strong capacity to form hydrogen bonds with water, the Cl−-water halogen bonds not only enable the structural diffusion of Zn2+ with better diffusion efficiency but also reduce the Zn2+ de-solvation energy barrier to promote uniform Zn nucleation. Consequently, the accelerated ions diffusion and homogeneous Zn deposition work in synergy to ensure high reversibility of Zn anode. These fundamental insights highlight the importance of hydrogen and halogen bonds in determining the dynamics and electrochemical behavior of electrolytes, providing theoretical guidance for the rational design of high-performance electrolytes.

Highly 002-Oriented Dendrite-Free Anode Achieved by Enhanced Interfacial Electrostatic Adsorption for Aqueous Zinc-Ion Batteries.

Rechargeable aqueous zinc-ion batteries (AZIBs) are gaining recognition as promising next-generation energy storage solution, due to their intrinsic safety and low cost. Nevertheless, the advancement of AZIBs is greatly limited by the abnormal growth of zinc dendrites during cycling. Electrolyte additives are effective at suppressing zinc dendrites, but there is currently no effective additive screening criterion. Herein, we propose employing the interfacial electrostatic adsorption strength of zinc ions for the initial screening of additives. Subsequently, dendrite-free plating is achieved by employing the anionic surfactant sodium dodecyl benzenesulfonate (SDBS) to enhance electrostatic adsorption. The cycled zinc anode exhibited a dense plating morphology and a high (002) orientation (I002/I101 = 22). The Zn||MnO2 full cell with SDBS exhibited a capacity retention of 85% after 1000 cycles at 1 A g-1. Furthermore, an instantaneous nucleation model and continuous nucleation model (CNM) are constructed to reveal the microscale plating/stripping dynamics under the scenarios of weak adsorption and strong adsorption. The CNM accurately explains the self-optimizing reconstruction of electrodes resulting from enhanced electrostatic adsorption. Our exploration was extended to other anionic surfactants (sodium dodecyl sulfate and disodium laureiminodipropionate), confirming the effectiveness of strong electrostatic adsorption in the screening of electrolyte additives.

Regulating zinc hydroxide sulfate (0 0 1) preferential growth and Zn (0 0 2) deposition by trace dibenzenesulfonimide additive toward long cycle lifespan for aqueous Zn-ion batteries

Regulating the zinc hydroxide sulfate (ZHS) growth orientation to construct interface layer with electronic insulation and high flux of Zn2+ is an efficient way to suppress parasitic side reactions and Zn dendrite in rechargeable aqueous zinc-ion batteries (ZIBs). Herein, a novel ZnSO4-based electrolyte with dibenzenesulfonimide (BBI) additive is proven able to maintain long-time cycle stabilities of Zn anode. The combination of experimental and precise testing technologies demonstrated that BBI additive can guide a surface-preferred ZHS (001) and Zn (002) crystal plane, as well as prevent the Zn corrosion and dendrite growth to smooth Zn deposition by adjusting the solid-phase interface energy. As a result, the Zn||Cu cells deliver an extended cycling lifespan over 1500 cycles with 99.7 % Coulombic efficiency at the current density of 2 mA cm−2, demonstrating an ultra-stable plating/stripping behavior. More encouragingly, the cyclic stability of Zn-MnO2 battery with the ZnSO4-BBI electrolyte can deliver a specific capacity of ∼165 mAh g−1 after 200 cycles at 1 C. This study clearly elucidates the interface behaviors to stabilize Zn anode, which contributes to a deep insight into the additive regulation mechanisms and brings a promising approach to solve the anode nuisance in aqueous metal batteries.

Roadmap for the Development of Transition Metal Oxide Cathodes for Rechargeable Zinc-Ion Batteries

Continued efforts towards the decarbonization of the power sector through an uptake of renewable energy generation, namely solar and wind, play a key role in the fight against climate change. However, due to their variable nature, the simultaneous implementation of energy storage solutions capable of ensuring a reliable delivery of energy at any time of day is of the utmost importance. Aqueous rechargeable zinc-ion batteries (RZIBs) are a promising technology for this end. Offering several advantages over lithium-ion batteries in terms of cost, environmental impact, and material abundance, the investment in RZIB research continues to grow. However, the realization of commercial RZIBs is currently hindered by the lack of cathode materials with adequate performance for long-term storage solutions. This is the case for manganese (e.g., MnO2, Mn2O3, Mn3O4) and vanadium (e.g., V2O5, VO2) based oxides, which exhibit considerable capacity fade during realistic charge and discharge times. While simple transition metal oxides (MyOx, M=transition metal) are one of the most studied classes of materials for RZIB cathodes, a literature survey shows that there are still many unexplored redox active elements and redox pairs which may be employed in next-generation RZIBs. Therefore, to accelerate the discovery of these novel cathode systems, we mapped the theoretical Zn intercalation potential for simple oxides from 12 different transition metals using Density Functional Theory (DFT) calculated thermodynamic properties. The screened elements were chosen upon considering their commercial availability, toxicity, price, and existence of previously reported structures containing zinc. During the present analysis, the feasibility of Zn intercalation for each system was accounted for by analyzing the atomic arrangement in the charged and discharged phases. Experimentally obtained Pourbaix Diagrams were also used to probe the electrochemical stability of the cathodes in aqueous solution, with the possibility of electrolyte degradation (oxygen or hydrogen evolution reaction) and competing reactions (metal dissolution or solid phase change) also considered. Experimental validation of the computationally predicted potentials was also done for select materials. The result for the 35+ redox pairs evaluated in this study provides a clear roadmap for the future development of RZIBs cathodes.

(Battery Student Slam 8 Award Winner) A Simple and Fast Method to Assemble Flexible and Stable Quasi-Solid-State Zn Ion Pouch Cell

Aqueous zinc-ion batteries (AZIBs) have been investigated intensively as effective energy storage devices that are environmentally friendly, safe, and have a lower cost than current Li-ion batteries.[1-5] Being outstandingly safe due to usage of non-organic electrolyte, AZIBs could also be used as power supply for wearable electronics. This also put high standard requirements in terms of flexibility, stability and electrochemical performance to AZIBs. On the other hand, the general challenges, such as the formation of the dendrites on the Zn anodes, hydrogen evolution and side reactions, have been obstructing the practical application of AZIBs. In this presentation, a simple method to assemble quasi-solid-state Zn ion pouch cell with excellent mechanical performance, flexibility and electrochemical performance was developed, combining in-situ electrodeposition of MnO2 cathode and aramid nano fiber-based hydrogel with Zn plate as anode. In-situ and cycling measurements of the electrodeposition of MnO2 on carbon nanotube mat shows excellent capacitance and superior cycling stability. In addition, Kevlar derivatized aramid nanofiber-based hydrogel shows extremely strong strength when combined with polyvinyl alcohol, which prolonged the lifetime of the cell by preventing Zn dendrite growth largely.[5,6] Moreover, the method to assemble the AZIBs pouch cell enables us to optimize the process, decrease the steps, and save time effectively by taking advantage of hydrogel formation stage and avoiding conventional verbose slurry-casting-drying steps. This work paves an efficient path to assemble flexible and stable AZIBs pouch cells with high capacity and cycling stability.[1] Tang, Boya, et al. "Issues and opportunities facing aqueous zinc-ion batteries." Energy & Environmental Science 12.11 (2019): 3288-3304.[2] Li, Chang, et al. "Toward practical aqueous zinc-ion batteries for electrochemical energy storage." Joule 6.8 (2022): 1733-1738.[3] Yu, Feng, et al. "An aqueous rechargeable zinc-ion battery on basis of an organic pigment." Rare Metals 41.7 (2022): 2230-2236.[4] Lin, Yuexing, et al. "Dendrite-free Zn anode enabled by anionic surfactant-induced horizontal growth for highly-stable aqueous Zn-ion pouch cells." Energy & Environmental Science 16.2 (2023): 687-697.[5] Wang, Peng, and Petru Andrei. "High Performance Separator and Hydrogel Based on Aramid Fibers for Zn Ion Batteries." Electrochemical Society Meeting s 242. No. 4. The Electrochemical Society, Inc., 2022.[6] Xu, Lizhi, et al. "Water‐rich biomimetic composites with abiotic self‐organizing nanofiber network." Advanced Materials 30.1 (2018): 1703343.

Development of Organic Positive Electrodes for Rechargeable Aqueous Zinc-Ion Batteries for Stationary Energy Storage Systems

The rising concern towards the amount of anthropogenic carbon emissions and their effects on the environment has motivated the transition away from fossil fuels. The implementation of renewable energy sources has promoted the decarbonization of the power sector, but the variability of wind and solar energy necessitates the parallel deployment of high-performance energy storage infrastructure to ensure a reliable on-demand supply of green electricity to the grid. To this end, aqueous rechargeable zinc-ion batteries (ZIBs) are a promising new option for stationary energy storage owing to their high safety and low cost, when compared to established storage technologies like lithium-ion batteries. However, ZIBs are still limited by several technological challenges that hinder their uptake for commercial energy storage installations. In particular, the positive electrode materials, mostly comprised of metal oxides, are restraining the energy density and stability of the batteries and are yet under investigation. Low cost, long cycle life, and natural abundance are required properties of materials used in batteries for stationary energy storage. The search for materials with these properties has motivated the investigation of alternatives to metal oxides. One group of materials attracting considerable research attention is organic compounds which offer advantages like their natural abundance and high theoretical capacities. In this work, we developed an organic positive electrode for ZIBs using carbonyl groups as redox-active centers to provide energy storage capacity at round-trip energy efficiencies that are higher than the conventionally utilized manganese oxide electrodes. Furthermore, we investigated the effects of the conductive carbon additive on the deliverable capacity of the battery and elucidated the charge storage mechanism of this positive electrode material through detailed characterization. The results indicated that both Zn2+ and H+ are involved in the energy storage process of this organic electrode material. In addition to studying the energy storage process, degradation mechanisms were identified through nuclear magnetic resonance (NMR) and mass spectroscopy (MS). Both dissolution of the reduced form of the active material from the electrode and the formation of unwanted decomposition products are important contributors to the capacity fade of the battery. The technological and scientific insights provided in this presentation will thereby contribute towards the development of high-performance and naturally abundant electrode materials for the next generation of ZIBs to enable clean energy grid storage.