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[Display omitted] Zinc metal anodes in aqueous electrolytes commonly face challenges such as dendrite growth and undesirable side reactions, limiting their application in the field of aqueous zinc-ion batteries (AZIBs) for energy storage. Drawing inspiration from industrial practices involving molybdenum salt solutions for metal modification, a polyoxometalate solution was formulated as a passivation solution for zinc anodes (referred to as MO solution). The formed passivation layer, referred to as the MO layer, exhibited a uniform and protective nature with a thickness of approximately 10 μm. The experimental results demonstrated that this passivation layer effectively suppressed side reactions at the zinc anode interface, as evidenced by lower corrosion current density for MO-Zn anodes. Additionally, the newly plated Zn was uniformly deposited atop the MO layer, ensuring coating integrity and inhibiting dendrite growth. As a result, under more demanding conditions such as a larger current of 8 mA cm−2, the MO-Zn anode displayed an extended cycle life exceeding 420 h in a symmetric battery, with an overpotential as low as 98 mV. This performance significantly outperformed that of commercially available pure Zn foils (with a cycle life of 60 h and an overpotential of 192 mV). Notably, a self-made Na-doped V 2 O 5 served as the cathode (referred to as NaVO), forming the MO-Zn//NaVO full battery. Even under high current test conditions of 2 A/g, the specific capacity of the MO-Zn//NaVO full battery remained substantial at 152.83 mAh/g after 1000 cycles. Furthermore, pouch batteries assembled with NaVO//MO-Zn successfully illuminated small bulbs. This study offers a viable optimization strategy for AZIB anodes and demonstrates the potential of using polyoxometalate solution for etching zinc anodes to inhibit dendrite growth and interfacial corrosion of zinc metal anodes. [ABSTRACT FROM AUTHOR]

[Display omitted] Aqueous zinc-ion batteries (AZIBs) have caused significant research attention due to their low redox potential of 0.76 V, high theoretical capacity of 820 mAh g−1. However, the dendrite growth of zinc anode and the side reactions caused by water seriously affect the cycle life of AZIBs. To solve the above problems, a new method of etching zinc anodes with CuCl 2 salt solution was designed, which the zinc anode was named CZn. The process resulted to a uniformly distributed micro gully morphology on the zinc surface, and providing an increased number of nucleation sites for zinc deposition and reducing local current density. The calculation results of exchange current density and activation energy show that CZn has stronger Zn/Zn2+ kinetic effect. At a current density of 5 mA cm−2 and an area capacity of 5 mAh cm−2, cycle life of the CZn symmetrical cell can reach 500 h, which is more than seven times that of the raw Zn symmetrical cell. This work proposes a simple method of zinc anode protection, which provides a new idea for zinc metal anode protection. [ABSTRACT FROM AUTHOR]

• Electrostatic spinning construction of 3D PVDF/PAN @Zn powder frameworks. • Mechanical stresses on fibre filaments and uniform stripping of zinc powder inhibit dendrite growth. • Larger surface area, suitable pore size and tunable N/P ratio are key merits. Zinc foil metal anodes in aqueous zinc ion batteries (AZIBs) are impaired by uncontrollable dendrite growth, resulting in low Coulombic efficiency (CE) and limited lifetime. The tunability of zinc powder provides a perfect alternative for anodes. But their rough spherical surfaces possibly make them more susceptible to corrosion and dendrite growth. We hereby utilise electrostatic spinning to weave zinc powder into polyacrylonitrile/ Polyvinylidene fluoride (PVDF/PAN) fiber filament to produce a new three-dimensional porous zinc anode (PF@Zn). Stable and flexible structure of the constructed fiber filament framework avoids direct contact of the aqueous electrolyte with the collector while relieving the stresses generated by dendrite growth. Moreover, when galvanizing or stripping, the zinc powder woven into the fiber network efficiently homogenizes the Zn2+ ion flux for a stable zinc cycle. Accordingly, the PF@Zn anode battery has a superior cycle life (240 h) and an increased Coulombic efficiency (99.1 %). An assembled C//PF@Zn capacitor has an impressive 96.6 % capacity retention after 3000 cycles. The study offers a scalable approach to modifying metal powder electrodes and transforming them into high-performance batteries. [ABSTRACT FROM AUTHOR]

The aqueous zinc-ion batteries (AZIBs) exhibit promising potential as a viable solution for large energy storage. Solving dendrite growth the surface of zinc metal anode in AZIBs is of great significance for its application in energy storage field. Among the many strategies for solving the zinc anode problem, the influence of zinc anode pretreatment is often ignored. The effect of sandpaper physical polishing on the performance of zinc anode was studied in this paper. The striated grooves formed on the surface of the zinc anode after sandpaper treatment make the zinc anode have a large specific surface area and a high zinc plating/stripping kinetics. It was found that sandpaper with larger mesh count (the finer the sandpaper) could reduce roughness and had the higher the electrochemical performance of zinc anodes. Consequently, the cycle life of 2000 M-Zn symmetric battery can reach 900 h under the current density of 0.5 mA cm−2. In the application of energy storage, the full battery composed of 2000 M-Zn and sodium doped V 2 O 5 cathode (NVO) still has a specific capacity of 148.6 mAh g−1 after 500 cycles, and has a stable rate performance. The pretreatment strategy of zinc anode holds significant importance in the applications of AZIBs. [Display omitted] • The properties of Zn anodes could be optimized by sandpaper pretreatment. • The morphology of striped gullies on the surface of Zn was constructed. • Effect of the mesh number of polished sandpaper on the properties of zinc anodes. • After fine sandpaper grinding, Zn surface was more conducive to electrolyte infiltration. [ABSTRACT FROM AUTHOR]

Aqueous zinc-ion batteries (AZIBs) are expected to be the next generation of energy storage devices, but severe dendrite growth hindering the large-scale application of AZIBs. In this paper, a citric acid (CA) etching method is used to optimize zinc anode, which is referred to as CA-Zn. After citric acid etching, the zinc anode surface was exposed to a high proportion of (002) crystal planes, and the stable (002) crystal planes inhibited the formation of zinc surface by-products. Moreover, acid etching etched micro-grooves on the zinc surface, which increased the electrochemically active surface area of the zinc anode. And the plating/stripping kinetics of Zn/Zn2+ was enhanced. Consequently, the CA-Zn symmetric battery has a stable cycle of 550 h at 1 mA cm−2 and 1 mAh cm−2. AZIBs composed of CA-Zn and activated carbon showed a specific capacity of up to 83.5 mAhg−1 and CE close to 100% during cycling 1500 cycles at a current density of 0.5 A g−1. This paper explores a new method to protect zinc metal by citric acid etching, which provides a new idea for future research. [Display omitted] • A simple method of etching zinc anodes surface in citric acid • More nucleation sites were constructed on the zinc surface. • The zinc anodes with more (002) crystal planes exposure were obtained. • The zinc anodes etched with citric acid have excellent electrochemical properties. [ABSTRACT FROM AUTHOR]