Metal zinc, with the advantages of low cost, low redox potential, and high capacity, is an ideal anode for aqueous zinc-ion batteries. Nonetheless, the inferior plating/stripping Coulombic efficiency and poor reversibility hinder its practical applications. To address the drawbacks, the zinc nucleation overpotential of different substrates is systematically investigated in asymmetric cells for the first time to confirm the suitable substrate with highly reversible plating/stripping behavior. As a result, Cu foam presents the low zinc nucleation overpotential of 65.2 mV and superior plating/stripping Coulombic efficiency close to 100%. Meanwhile, Cu foam is optimized as the carrier for the deposition of metallic zinc and the preparation of the Zn@Cu foam anode through the electrochemical deposition method. Besides, the Zn@Cu foam anode holds the low initial polarization voltage and stable voltage hysteresis profile with negligible voltage polarization in the symmetric cell. Furthermore, coupled with the β-MnO2 cathode, it could exhibit an outstanding cycling ability with a capacity of 172.8 mA h g–1 after 600 cycles at 1 A g–1 in the full cell, corresponding to an extremely low decay rate of 0.0218% per cycle.

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The rampant dendrites and hydrogen evolution reaction (HER) resulting from the turbulent interfacial evolution at the anode/electrolyte are the main culprits of short lifespan and low Coulombic efficiency of Zn metal batteries. In this work, a versatile protective coating with excellent zincophilic and amphoteric features is constructed on the surface of Zn metal (ZP@Zn) as dendrite-free anodes. This kind of protective coating possesses the advantages of reversible proton storage and rapid desolvation kinetics, thereby mitigating the HER and facilitating homogeneous nucleation concomitantly. Furthermore, the space charge polarization effect promotes charge redistribution to achieve uniform Zn deposition. Accordingly, the ZP@Zn symmetric cell manifests excellent reversibility at an ultrahigh cumulative plating capacity of 4700 mAh cm À 2 and stable cycling at 80 % depth of discharge (DOD). The ZP@Zn//V 6 O 13 pouch cell also reveals superior cycling stability with a high capacity of 326.6 mAh g À 1 .

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This paper examines whether structural breaks contain incremental information for forecasting the volatility of copper futures. Considering structural breaks in volatility, we develop four heterogeneous autoregressive (HAR) models based on classical or latest HAR‐type models. Subsequently, we apply these models to forecast volatility in the copper futures market. The empirical results reveal that our models exhibit better in‐sample and out‐of‐sample performances than classical or latest HAR‐type models. This suggests that structural breaks contain incremental prediction information for the volatility of copper futures. More importantly, we argue that considering structural breaks can improve the performances of most of existing HAR‐type models. Highlights There are many structural break points in return volatility of the copper futures. We propose 12 new heterogeneous autoregressive models. Our models outperform the existing heterogeneous autoregressive models. Structural breaks contain additional ex ante information for volatility forecasting. The ex ante information is obvious in forecasting mid‐ and long‐term volatilities.

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