Metal‐Organic Framework Integrated Anodes for Aqueous Zinc‐Ion Batteries

Abstract

decreases the cost because it eliminates the necessity of having an inert atmosphere or using organic solvents. Thus, Zn-based energy storage systems such as Zn-ion, [5,6] Zn-alkali, [2,7] Zn-flow, [8] Zn-I 2 , [9] Zn-air, [10] and Zn-ion capacitors [11,12] have received attention because of their practicality and good performance. The easy and scalable production of Zn electrodes is crucial for securing the continued development of improved Zn-based battery systems, but recent research has highlighted the problem of dendrite formation caused by non-uniform charge distribution and side reactions (hydrogen evolution, Zn corrosion) during plating and stripping which causes severe deterioration of Zn batteries, and significantly limits their efficiency and life. Because of dendrite growth, such devices suffer from a short cycle life, capacity fade, and a high possibility of internal short circuit formation and safety problems. Dendrite growth is not only a challenging problem for Zn batteries but is also a problem for Li-metal batteries, and suppression of dendrite formation in anodes is a great challenge for battery research. [13] Although there is a considerable effort to suppress dendrite formation, it still remains the most crucial problem for batteries. To overcome this problem, several strategies have been used, that is, redesigning the anode, [2,14] composite formation or anode surface modifications, [15] reformulating electrolytes with additives, and the use of solid-state electrolytes. [3,16,17] Uniform charge distribution on the anode surface is essential for eliminating this problem.ZIF-8, one of the zeolitic imidazole frameworks (a subgroup of the metal-organic frameworks [MOFs]), has a Zn-coordinated crystal structure and high microporosity. [12,18] The use of ZIF-8-derived carbon nanoparticles as a host for electrodeposited Zn has been reported in the literature. [9] We reasoned that a monolithic (conformal) ZIF-8 layer that is directly grown on Zn metal might be a unique strategy to ensure a uniform charge and ion distribution at the anode-electrolyte interface. MOF-integrated Zn anodes might facilitate reversible Zn plating and stripping cycles, and prevent dendrite formation and side reactions. It is also possible that pyrolyzed MOF-integrated Zn anodes might have a similar mechanism and electrochemical properties due to their N-content, porosity, and hydrophilicity.Here, we report the design and construction of novel MOFbased Zn anodes to achieve the above-mentioned goals for Znbased energy storage systems. The surface of a bare Zn foil was selectively oxidized and MOFs were directly grown on it by a wet chemistry method. The resulting anodes were used Zinc-based batteries have a high capacity and are safe, cost-effective, environmentally-friendly, and capable of scalable production. However, dendrite formation and poor reversibility hinder their performance. Metal-organic framework (MOF)-based Zn anodes are made by wet chemistry to address these issues. These MOF-based anodes exhibit high effi...

An Interface‐Bridged Organic–Inorganic Layer that Suppresses Dendrite Formation and Side Reactions for Ultra‐Long‐Life Aqueous Zinc Metal Anodes

“…[21] To address the above issues,t he currently reported solutions can be divided into two aspects:s uppressing dendrite formation and minimizing side reactions.D endrite suppression can be achieved by introducing coating layers on Zn anode surface,which effectively modified the current and electrolyte flux on anode surface,s uch as CaCO 3 and SiO 2 layer, [22] porous active carbon layer and reduced graphene oxide (rGO) layer, [23,24] and so on. Furthermore,m any strategies have also been reported for relieving the side reactions beside suppressing dendrites,i ncluding coating az incophilic protective layer, [25] replacing ZnSO 4 with Zn-(CF 3 SO 3 ) 2 , [26] using electrolyte additives, [27][28][29] adoption of ah ighly concentrated zincic salt as electrolyte, [30] using modified conductive host, [31][32][33][34] employing single ion conduc-tive electrolyte, [35,36] alloying with Al, [37] adopting gel electrolyte or all solid electrolyte, [38][39][40] coating inorganic layer, [41][42][43][44] or organic (polyamide) layer. [45] Indeed, the side reactions and dendrite are very important issues for long life AZBs.…”

A Fully Aqueous Hybrid Electrolyte Rechargeable Battery with High Voltage and High Energy Density

“…It could be ascribed to the smaller exchange current density and large interfacial resistance of Zn metal in neutral electrolyte than that in alkaline electrolyte ( Figure S4, Supporting Information). [49,50] Spinel LiMn 2 O 4 is selected as the positive electrode for its superior capability and higher redox potential compared to most positive electrode materials in traditional ARLBs, such as LiFePO 4 . Most importantly, it possesses excellent cycling stability and low cost.…”

Issues and solutions toward zinc anode in aqueous zinc‐ion batteries: A mini review

“…55,69 To suppress dendrites, an ideal coating layer should possess certain stability, high ionic conductivity, and good affinity with electrolytes. The reported coatings contain metal-organic frameworks (MOF), 66 carbon matrix, 70 inorganic metal oxides, 49 polymers, 71 and so on. UiO-66 MOF solid electrolyte coating with nanoscale wetting effects demonstrated significantly decreased ion transmission resistance and nucleation barrier during the Zn deposition.…”