Despite the advantages of aqueous zinc (Zn) metal batteries (AZMB) like high specific capacity (820 mAh g−1and 5,854 mAh cm−3), low redox potential (−0.76 V vs. the standard hydrogen electrode), low cost, water compatibility, and safety, the development of practically relevant batteries is plagued by several issues like unwanted hydrogen evolution reaction (HER), corrosion of Zn substrate (insulating ZnO, Zn(OH)2, Zn(SO4)x(OH)y, Zn(ClO4)x(OH)yetc. passivation layer), and dendrite growth. Controlling and suppressing HER activity strongly correlates with the long‐term cyclability of AZMBs. Therefore, a precise quantitative technique is needed to monitor the real‐time dynamics of hydrogen evolution during Zn electrodeposition. In this study, we quantify hydrogen evolution using in situ electrochemical mass spectrometry (ECMS). This methodology enables us to determine a correction factor for the faradaic efficiency of this system with unmatched precision. For instance, during the electrodeposition of zinc on a copper substrate at a current density of 1.5 mA/cm2for 600 seconds, 0.3 % of the total charge is attributed to HER, while the rest contributes to zinc electrodeposition. At first glance, this may seem like a small fraction, but it can be detrimental to the long‐term cycling performance of AZMBs. Furthermore, our results provide insights into the correlation between HER and the porous morphology of the electrodeposited zinc, unravelling the presence of trapped H2and Zn corrosion during the charging process. Overall, this study sets a platform to accurately determine the faradaic efficiency of Zn electrodeposition and provides a powerful tool for evaluating electrolyte additives, salts, and electrode modifications aimed at enhancing long‐term stability and suppressing the HER in aqueous Zn batteries.
Despite the advantages of aqueous zinc (Zn) metal batteries (AZMB) like high specific capacity (820 mAh g−1and 5,854 mAh cm−3), low redox potential (−0.76 V vs. the standard hydrogen electrode), low cost, water compatibility, and safety, the development of practically relevant batteries is plagued by several issues like unwanted hydrogen evolution reaction (HER), corrosion of Zn substrate (insulating ZnO, Zn(OH)2, Zn(SO4)x(OH)y, Zn(ClO4)x(OH)yetc. passivation layer), and dendrite growth. Controlling and suppressing HER activity strongly correlates with the long‐term cyclability of AZMBs. Therefore, a precise quantitative technique is needed to monitor the real‐time dynamics of hydrogen evolution during Zn electrodeposition. In this study, we quantify hydrogen evolution using in situ electrochemical mass spectrometry (ECMS). This methodology enables us to determine a correction factor for the faradaic efficiency of this system with unmatched precision. For instance, during the electrodeposition of zinc on a copper substrate at a current density of 1.5 mA/cm2for 600 seconds, 0.3 % of the total charge is attributed to HER, while the rest contributes to zinc electrodeposition. At first glance, this may seem like a small fraction, but it can be detrimental to the long‐term cycling performance of AZMBs. Furthermore, our results provide insights into the correlation between HER and the porous morphology of the electrodeposited zinc, unravelling the presence of trapped H2and Zn corrosion during the charging process. Overall, this study sets a platform to accurately determine the faradaic efficiency of Zn electrodeposition and provides a powerful tool for evaluating electrolyte additives, salts, and electrode modifications aimed at enhancing long‐term stability and suppressing the HER in aqueous Zn batteries.
more » « less- Award ID(s):
- 2327563
- NSF-PAR ID:
- 10486525
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Angewandte Chemie International Edition
- Volume:
- 63
- Issue:
- 11
- ISSN:
- 1433-7851
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Ever-increasing demands for energy, particularly being environmentally friendly have promoted the transition from fossil fuels to renewable energy.1Lithium-ion batteries (LIBs), arguably the most well-studied energy storage system, have dominated the energy market since their advent in the 1990s.2However, challenging issues regarding safety, supply of lithium, and high price of lithium resources limit the further advancement of LIBs for large-scale energy storage applications.3Therefore, attention is being concentrated on an alternative electrochemical energy storage device that features high safety, low cost, and long cycle life. Rechargeable aqueous zinc-ion batteries (ZIBs) is considered one of the most promising alternative energy storage systems due to the high theoretical energy and power densities where the multiple electrons (Zn2+) . In addition, aqueous ZIBs are safer due to non-flammable electrolyte (e.g., typically aqueous solution) and can be manufactured since they can be assembled in ambient air conditions.4As an essential component in aqueous Zn-based batteries, the Zn metal anode generally suffers from the growth of dendrites, which would affect battery performance in several ways. Second, the led by the loose structure of Zn dendrite may reduce the coulombic efficiency and shorten the battery lifespan.5
Several approaches were suggested to improve the electrochemical stability of ZIBs, such as implementing an interfacial buffer layer that separates the active Zn from the bulk electrolyte.6However, the and thick thickness of the conventional Zn metal foils remain a critical challenge in this field, which may diminish the energy density of the battery drastically. According to a theretical calculation, the thickness of a Zn metal anode with an areal capacity of 1 mAh cm-2is about 1.7 μm. However, existing extrusion-based fabrication technologies are not capable of downscaling the thickness Zn metal foils below 20 μm.
Herein, we demonstrate a thickness controllable coating approach to fabricate an ultrathin Zn metal anode as well as a thin dielectric oxide separator. First, a 1.7 μm Zn layer was uniformly thermally evaporated onto a Cu foil. Then, Al2O3, the separator was deposited through sputtering on the Zn layer to a thickness of 10 nm. The inert and high hardness Al2O3layer is expected to lower the polarization and restrain the growth of Zn dendrites. Atomic force microscopy was employed to evaluate the roughness of the surface of the deposited Zn and Al2O3/Zn anode structures. Long-term cycling stability was gauged under the symmetrical cells at 0.5 mA cm-2for 1 mAh cm-2. Then the fabricated Zn anode was paired with MnO2as a full cell for further electrochemical performance testing. To investigate the evolution of the interface between the Zn anode and the electrolyte, a home-developed in-situ optical observation battery cage was employed to record and compare the process of Zn deposition on the anodes of the Al2O3/Zn (demonstrated in this study) and the procured thick Zn anode. The surface morphology of the two Zn anodes after circulation was characterized and compared through scanning electron microscopy. The tunable ultrathin Zn metal anode with enhanced anode stability provides a pathway for future high-energy-density Zn-ion batteries.
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J Am Chem Soc 2013, 135 (4), 1167-76.Li, C.; Xie, X.; Liang, S.; Zhou, J., Issues and Future Perspective on Zinc Metal Anode for Rechargeable Aqueous Zinc‐ion Batteries.
Energy & Environmental Materials 2020, 3 (2), 146-159.Jia, H.; Wang, Z.; Tawiah, B.; Wang, Y.; Chan, C.-Y.; Fei, B.; Pan, F., Recent advances in zinc anodes for high-performance aqueous Zn-ion batteries.
Nano Energy 2020, 70 .Yang, J.; Yin, B.; Sun, Y.; Pan, H.; Sun, W.; Jia, B.; Zhang, S.; Ma, T., Zinc Anode for Mild Aqueous Zinc-Ion Batteries: Challenges, Strategies, and Perspectives.
Nanomicro Lett 2022, 14 (1), 42.Yang, Q.; Li, Q.; Liu, Z.; Wang, D.; Guo, Y.; Li, X.; Tang, Y.; Li, H.; Dong, B.; Zhi, C., Dendrites in Zn-Based Batteries.
Adv Mater 2020, 32 (48), e2001854.Acknowledgment
This work was partially supported by the U.S. National Science Foundation (NSF) Award No. ECCS-1931088. S.L. and H.W.S. acknowledge the support from the Improvement of Measurement Standards and Technology for Mechanical Metrology (Grant No. 22011044) by KRISS.
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Abstract Aqueous zinc metal batteries (AZMB) are emerging as a promising alternative to the prevailing existing Lithium‐ion battery technology. However, the development of AZMBs is hindered due to challenges including dendrite formation, hydrogen evolution reaction (HER), and ZnO passivation on the anode. Here, a tetraalkylsulfonamide (TAS) additive for suppressing HER, dendrite formation, and enhancing cyclability is rationally designed. Only 1 m
m TAS is found that can effectively displace water molecules from the Zn2+solvation shell, thereby altering the solvation matrix of Zn2+and disrupting the hydrogen bond network of free water, as demonstrated through67 Zn and1H nuclear magnetic resonance spectroscopy, high‐resolution mass spectrometry (HRMS), and density functional theory (DFT) studies. Voltammetry synchronized with in situ monitoring of the electrode surface reveals suppressed dendritic growth and HER in the presence of TAS. Electrochemical mass spectrometry (ECMS) captures real‐time HER suppression during Zn electrodeposition, revealing the ability of TAS to suppress the HER by an order of magnitude. A ≈25‐fold cycle life improvement from ≈100 h to over 2500 h in coin cells cycled in the presence of TAS. Furthermore, by suppressing passivation product formation, it is demonstrated that strategy robustly maximizes the stability of Zn metal anodes. -
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Abstract Aqueous zinc-ion batteries, in terms of integration with high safety, environmental benignity, and low cost, have attracted much attention for powering electronic devices and storage systems. However, the interface instability issues at the Zn anode caused by detrimental side reactions such as dendrite growth, hydrogen evolution, and metal corrosion at the solid (anode)/liquid (electrolyte) interface impede their practical applications in the fields requiring long-term performance persistence. Despite the rapid progress in suppressing the side reactions at the materials interface, the mechanism of ion storage and dendrite formation in practical aqueous zinc-ion batteries with dual-cation aqueous electrolytes is still unclear. Herein, we design an interface material consisting of forest-like three-dimensional zinc-copper alloy with engineered surfaces to explore the Zn plating/stripping mode in dual-cation electrolytes. The three-dimensional nanostructured surface of zinc-copper alloy is demonstrated to be in favor of effectively regulating the reaction kinetics of Zn plating/stripping processes. The developed interface materials suppress the dendrite growth on the anode surface towards high-performance persistent aqueous zinc-ion batteries in the aqueous electrolytes containing single and dual cations. This work remarkably enhances the fundamental understanding of dual-cation intercalation chemistry in aqueous electrochemical systems and provides a guide for exploring high-performance aqueous zinc-ion batteries and beyond.
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Abstract In this work, a functional covalent gel material is developed to resolve the severe dendritic growth and hydrogen evolution reaction toward Zn/electrolyte interface in aqueous zinc‐ion batteries (ZIBs). A covalent gel layer with superior durability forms homogeneously on the surface of Zn foil. The covalent gel with triazole functional groups can uniformize the transport of Zn2+due to the interactions between Zn2+ions and the triazole groups in the covalent gel. As a consequence, the symmetrical battery with triazole covalent gel maintains stable Zn plating/stripping for over 3000 h at 1 mA cm−2and 1 mAh cm−2, and the full cell combined with a V2O5cathode operates steadily and continuously for at least 1800 cycles at 5 A g−1with a capacity retention rate of 67.0%. This work provides a train of thought to develop stable covalent gels for the protection of zinc anode toward high‐performance ZIBs.
