Synergistic integration of in situ Grown ZIF-71 and organic additives toward a stable cooperative interface in advanced aqueous zinc-ion batteries

The further development of aqueous zinc batteries is restricted by their low-temperature performance. At present, introducing organic additives into aqueous electrolytes is a universal strategy to reduce the freezing point and improve the low-temperature performance. However, the effect of organic additives on charge carriers is neglected, and the corresponding impact on low-temperature performance is not clear. Herein, a common organic additive (propylene carbonate, PC) was introduced into the Zn(CF3SO3)2 electrolyte to explore the effect of organic additives on charge carriers. PC optimizes the coordination environment of water in the electrolyte, which reduces the freezing point. However, this changed coordination environment of water decreases the adsorption energy of water on the surface of the oxide cathode, which restrains the proton insertion behavior. With the increase of PC, the proton insertion behavior is restrained gradually. At -40 °C, a Zn||CaV8O20·nH2O battery with pure Zn(CF3SO3)2 electrolyte fails because of the freezing of the electrolyte. However, the Zn||CaV8O20·nH2O battery based on the PC-optimized electrolyte with proton insertion still displays a capacity of 177 mAh g-1 at 0.5 A g-1 at -40 °C, which is obviously higher than that (111 mAh g-1) based on the PC-optimized electrolyte without proton insertion. This work provides a theoretical basis for selecting suitable organic additives to develop low-temperature aqueous zinc batteries.

Lithium-ion batteries (LIBs) have become essential for storing electrical energy in portable electronics and electric vehicles due to their high energy density, light weight, and excellent reversibility and cyclability. Despite their widespread use across various electronic devices, their use in Energy Storage Systems (ESS) with substantial capacities is limited by safety concerns. This is because enhancing storage capacity also increases the volume of flammable organic solvents. As a result, there have been significant research efforts toward developing safer alternatives, such as aqueous batteries, with aqueous Zn-ion batteries (AZIBs) being a representative example. Compared to conventional LIBs, ZIBs are more cost-effective, safer, and environmentally friendly. However, the practical application of AZIBs faces significant challenges, particularly regarding Zn dendrite growth, corrosion, and the hydrogen evolution reaction (HER) on the Zn anode side, which critically reduces the cyclability of ZIBs. To mitigate these challenges, several solutions have been proposed, such as modifying the Zn ion hydration structure, using water-in-salt electrolytes, and adding additives to modulate the properties of the Zn surface. In this presentation, we will introduce organic additives aimed at regulating the electrochemical Zn growth to enhance the cyclability of the Zn anode. These organic additives influence the kinetics of the Zn deposition/dissolution processes and alter the morphology of the Zn deposits. We will discuss the effect of organic additives on Zn growth and the cyclability of Zn||Zn symmetric cells in relation to the molecular structure and adsorption behavior of the additives. By considering all results, we will determine which functional group is critical for controlling Zn growth and propose the most effective organic additive for enhancing the performance of AZIBs.

Optimization strategies toward advanced aqueous zinc-ion batteries: From facing key issues to viable solutions

Aqueous zinc-ion batteries (AZIBs) represent viable options for large-scale energy storage, attributed to their high theoretical capacity, availability of resources, and intrinsic safety features. However, the zinc-water interface poses significant challenges including dendrite growth, hydrogen evolution, and corrosion, which considerably restrict battery performance. This review systematically examines organic additive strategies for zinc anode interface regulation in AZIBs. Structure-property relationships are established correlating molecular design with interfacial behavior through three fundamental mechanisms, which are electric double layer (EDL) modulation, solvation structure optimization via coordination effects, and controlled solid electrolyte interphase (SEI) formation. The review analyzes adsorption mechanisms of organic additives, distinguishing between physical adsorption-based and SEI-forming additives, where the former dynamically modulates the interfacial environment, while the latter establishes durable protective layers. Multifunctional additives integrating multiple regulatory mechanisms demonstrate superior performance optimization. Comparative analysis reveals that liquid organic additives excel in solvation structure regulation, whereas solid additives show advantages in interfacial adsorption and SEI engineering. Through systematic analysis of reported molecules, design principles are established linking molecular features to interfacial properties, providing guidance for rational development of next-generation organic additives in high-performance AZIBs.

A strategy associated with conductive binder and 3D current collector for aqueous zinc-ion batteries with high mass loading

Synergistic effect of the co-solvent induced interfacial chemistries in aqueous Zn batteries

Investigation of Na6V10O28 as a promising rechargeable aqueous zinc-ion batteries cathode

Metallic silver doped vanadium pentoxide cathode for aqueous rechargeable zinc ion batteries

The electricity grids with high stability and reliability require a desired balance of energy supply and demand. As the typical sustainable energy, the intermittent solar and wind would result in electricity grid instability. Aqueous batteries have been considered to be appealing stationary power sources for sustainable energy. Advanced aqueous batteries can address the safety concern derived from the employment of highly toxic and flammable organic solvents in lithium-ion batteries together with the poor cycle life presented in commercialized aqueous rechargeable batteries. This review will introduce several kinds of newly developed aqueous batteries, including aqueous Li (Na)-ion batteries, zinc anode-based batteries (Zn-metal oxide, Zn-air, Zn–Br2, and Zn–Ni(OH)2 batteries), and Ni(OH)2 cathode-based batteries (Ni(OH)2–MH and Ni(OH)2-organic composite batteries). The materials, mechanisms, and battery techniques for the above aqueous batteries will be introduced in detail. The status and challenges for the application of aqueous batteries will also be discussed. The status for advanced aqueous batteries are summarized in detail. The challenges for the application of aqueous batteries are discussed.

Interface challenges and optimization strategies for aqueous zinc-ion batteries

Although the research on aqueous batteries employing metal as the anode is still mainly focused on the aqueous zinc-ion battery, aqueous iron-ion batteries are considered as promising aqueous batteries owing to the lower cost, higher specific capacity, and better stability. However, the sluggish Fe2+ (de)intercalation leads to unsatisfactory specific capacity and poor electrochemical stability, which makes it difficult to find cathode materials with excellent electrochemical properties. Herein, phenylamine (PA)-intercalated VOPO4 materials with expanded interlayer spacing are synthesized and applied successfully in aqueous iron-ion batteries. Owing to enough diffusion space from the expanded interlayer, which can boost fast Fe2+ diffusion, the aqueous iron-ion battery shows a high specific capacity of 170 mAh g-1 at 0.2 A g-1 , excellent rate performance, and cycle stability (96.2% capacity retention after 2200 cycles). This work provides a new direction for cathode material design in the development of aqueous iron-ion batteries.

Vanadium oxide nanospheres encapsulated in N-doped carbon nanofibers with morphology and defect dual-engineering toward advanced aqueous zinc-ion batteries

Aqueous zinc batteries (AZBs) have emerged as an alternative of lithium-ion batteries (LIBs) due to their potential for high energy density, safety, and cost-effectiveness. However, the long-term stability of zinc metal anode has been hindered by hydrogen evolution reaction (HER), dendrite growth, and byproduct formation (Zn4(OH)6SO4·xH2O, zinc basic sulfate). To stabilize the zinc metal anode, various strategies such as surface coating and electrolyte design have been studied. In particular, electrolyte additives are regarded as practical strategies owing to low cost and simple methods.To improve the stability of zinc metal anode, organic additive was introduced. During the plating/stripping process, the enormous dendrites were observed in blank electrolyte via side-view operando X-ray imaging. Furthermore, a number of H2 bubbles were generated at the electrode surface. On the contrary, when the organic additive was added into electrolyte, the smooth surface with homogeneous deposition was confirmed and the formation of hydrogen gas was rarely observed. In addition, the uniform Zn deposition with organic additive was also verified through top-view operando optical imaging, whereas the black spots were formed on the surface without the additive, which represent the Zn dendrite formation. Based on the superior stability, the Zn||Cu half-cell with the organic additive maintained the steady voltage profile over 1600 h at 1 mA cm-2, while the short circuit occurred after 100 h without the additive. Figure 1

Aqueous rechargeable zinc-ion batteries (ZIBs) have attracted considerable attention as one of the most promising energy storage systems for the grid-scale application owing to the natural merits of metallic Zn, including a high theoretical capacity, suitable redox potential, low cost, high safety, and eco-friendliness. However, the existing aqueous ZIBs are far from satisfying the requirements of practical applications. Significant challenges hindering the further development of ZIBs come from the low utilization and poor cycling stability of cathodes and limited reversibility of Zn anodes associated with dendrite growth, corrosion, and passivation. To date, enormous efforts have been devoted to developing high-performance cathode materials, reliable electrolytes, and stable Zn anodes to achieve ZIB with high energy and power densities and long cycle life. These progresses have been reviewed in this dissertation. Regarding the main issues of ZIBs, the dissertation covered both the cathode and anode to comprehensively improve the electrochemical performance of ZIBs. For the cathode, high-performance manganese oxide-based cathode materials have been developed by in-situ electrochemical activation of MnS, and rational design of hierarchical core-shell MnO2@carbon nanofiber structures. To further understand the underlying reasons for the enhanced electrochemical performance, the charge storage mechanisms of manganese oxide-based cathodes in ZIBs have been in-depth investigated. With respect to the Zn anode, a thin polyvinyl alcohol (PVA) coating layer on the Zn anode has enabled dendrite-free, long-life aqueous Zn batteries by effectively regulating the interfacial ion diffusion and inducing the homogeneous Zn nucleation and deposition of stacked plates with preferentially crystallographic orientation along (002)Zn planes. This work is expected to provide facile and low-cost approaches for developing high-performance, cost-effective, and stable aqueous ZIBs and shed light on a new mechanistic understanding of manganese oxide-based cathodes.

Rechargeable aqueous zinc-ion batteries (ZIBs) have attracted much attention recently due to the high abundance, low cost, high theoretical capacity up to 820 mAh g-1 with multi-valent charge carrier, and compatibility with aqueous electrolyte of the zinc anode.[1] Especially, the introduction of neutral or mild acidic electrolyte greatly improves the reversibility of zinc anode compared to conventional alkaline ZIBs.[2] Among all the cathode candidates, MnO2 is most attractive due to its relatively high energy density, low toxicity and low cost.[3] However, MnO2 electrode suffers from capacity fading during cycling mainly due to Mn dissolution and structural change. The addition of Mn2+ into the mild acidic electrolyte is a common method to suppress Mn dissolution.[4] Other strategies like structural design and surface coatings are also developed to suppress Mn dissolution.[5, 6] Though the cycle performance still cannot meet the demand of application, as the irreversible formation of inactive ZnMn2O4 during cycles still requires to be tackled.Here, we proposed Bi2O3 as a facile electrode additive in the electrode to suppress ZnMn2O4 formation and improve the cyclability of commercial electrolytic manganese dioxide (EMD). XRD, in-situ pH measurements and ICP tests suggest that inactive ZnMn2O4 is formed upon cycling due to the interaction between MnO2 and zincate ions in the electrolyte from localized increase in pH, and Bi2O3 dissolves into the electrolyte in the presence of zincate ions and forms a complex with the zincate ions to suppress the reaction pathway. A high capacity of 269 mAh g-1 is maintained at 100 mA g-1 after 50 cycles with a capacity retention of 91.5% when EMD with 10 wt% of Bi2O3 is tested in ZnSO4 electrolyte without Mn2+ additive. Combining both Bi2O3 electrode additive and Mn2+ electrolyte additive, EMD can maintain a stable capacity of 190 mAh g-1 for 1000 cycles at 1000 mA g-1 (about 3.3C). More characterizations are underway to further understand the role of Bi2O3 and the results will be shown during the meeting.Reference:[1] B. Tang, L. Shan, S. Liang, J. Zhou, Issues and opportunities facing aqueous zinc-ion batteries, Energy & Environmental Science, 12 (2019) 3288-3304.[2] J. Hao, X. Li, X. Zeng, D. Li, J. Mao, Z. Guo, Deeply understanding the Zn anode behaviour and corresponding improvement strategies in different aqueous Zn-based batteries, Energy & Environmental Science, 13 (2020) 3917-3949.[3] N. Zhang, X. Chen, M. Yu, Z. Niu, F. Cheng, J. Chen, Materials chemistry for rechargeable zinc-ion batteries, Chemical Society Reviews, 49 (2020) 4203-4219.[4] H. Pan, Y. Shao, P. Yan, Y. Cheng, K.S. Han, Z. Nie, C. Wang, J. Yang, X. Li, P. Bhattacharya, Reversible aqueous zinc/manganese oxide energy storage from conversion reactions, Nature Energy, 1 (2016) 1-7.[5] J. Huang, Z. Wang, M. Hou, X. Dong, Y. Liu, Y. Wang, Y. Xia, Polyaniline-intercalated manganese dioxide nanolayers as a high-performance cathode material for an aqueous zinc-ion battery, Nature communications, 9 (2018) 1-8.[6] B. Wu, G. Zhang, M. Yan, T. Xiong, P. He, L. He, X. Xu, L. Mai, Graphene scroll‐coated α‐MnO2 nanowires as high‐performance cathode materials for aqueous Zn‐ion battery, Small, 14 (2018) 1703850. Figure 1