Biomimetic Honeycomb Zn Anode Enabled Multi-Field Regulation toward Highly Stable Flexible Zn-Ion Batteries

Flexible Zn-ion batteries (ZIBs) emerge as a promising entrant for flexible and safe energy systems in the post-Li era, while the instability of Zn anode including inferior flexibility, uncontrollable plating, and dendrite growth remains a challenge. Naturally inspired, a topology-optimized biomimetic honeycomb Zn (BH-Zn) anode through mechanical-electrochemical processing is demonstrated. Numerical simulations and experimental observations reveal the BH-Zn engenders smooth current–stress–thermal field distributions, concurrently realizing the multi-field regulation effect and boosted stability. After in situ alloying, the BH-Zn enables half-diminished voltage polarization, superior electrochemical stability of 2000 h cycling, and thermal stability even at 30 mA cm⁻². Moreover, the assembled ZIBs manifest over 20 times enhanced capacity retention and are integrated as a self-powered wearable system for real-time health monitoring. This strategy can be extended to customizable metal anodes and promises to be applied in stable flexible batteries.     

Nickel@Nickel Oxide Core–Shell Electrode with Significantly Boosted Reactivity for Ultrahigh‐Energy and Stable Aqueous Ni–Zn Battery

The main bottlenecks of aqueous rechargeable Ni–Zn batteries are their relatively low energy density and poor cycling stability, mainly arising from the low capacity and inferior reversibility of the current Ni‐based cathodes. Additionally, the complicated and difficult‐to‐scale preparation procedures of these cathodes are not promising for large‐scale energy storage. Here, a facile and cost‐effective ultrasonic‐assisted strategy is developed to efficiently activate commercial Ni foam as a robust cathode for a high‐energy and stable aqueous rechargeable Ni–Zn battery. 3D Ni@NiO core–shell electrode with remarkably boosted reactivity and an area of 300 cm² is readily obtained by this ultrasonic‐assisted activation method (denoted as SANF). Benefiting from the in situ formation of electrochemically active NiO and porous 3D structure with a large surface area, the as‐fabricated SANF//Zn battery presents ultrahigh capacity (0.422 mA h cm^?2) and excellent cycling durability (92.5% after 1800 cycles). Moreover, this aqueous rechargeable SANF//Zn battery achieves an impressive energy density of 15.1 mW h cm^?3 (0.754 mW h cm^?2) and a peak power density of 1392 mW cm^?3, outperforming most reported aqueous rechargeable energy‐storage devices. These findings may provide valuable insights into designing large‐scale and high‐performance 3D electrodes for aqueous rechargeable batteries.     

A Sieve‐Functional and Uniform‐Porous Kaolin Layer toward Stable Zinc Metal Anode

Zinc metal is considered as one of the best anode choices for rechargeable aqueous Zn‐based batteries due to its high specific capacity, abundance, and safety. However, dendrite and corrosion issues remain a challenge for this system. Herein, sieve‐element function (selective channel of Zn²⁺) and uniform‐pore distribution (≈3.0 nm) of a kaolin‐coated Zn anode (KL‐Zn) is proposed to alleviate these problems. Based on the artificial Zn metal/electrolyte interface, the KL‐Zn anode not only ensures dendrite‐free deposition and long‐time stability (800 h at 1.1 mA h cm^?2), but also retards side reactions. As a consequence, KL‐Zn/MnO₂ batteries can deliver high specific capacity and good capacity retention as well as a reasonably well‐preserved morphology (KL‐Zn) after 600 cycles at 0.5 A g^?1. This work provides a deep step toward high‐performance rechargeable Zn‐based battery system.     

Cu-Modified Ti3C2Cl2 MXene with Zincophilic and Hydrophobic Characteristics as a Protective Coating for Highly Stable Zn Anode

Zn anode is a promising candidate for aqueous batteries, but suffers from the dendrite growth and side reaction issues, leading to short cycling life and unsatisfactory reversibility. Herein, a Cu-modified Ti₃C₂Cl₂ MXene (Cu-MXene) with high zincophilic and hydrophobic property is prepared with a one-step molten salt etching method. Serving as a protective coating on Zn anode, the Cu-MXene can provide massive nucleation sites and uniformize the charge distribution, leading to homogenous Zn deposition. Moreover, the hydrophobic coating can prevent the Zn anode from the aqueous electrolyte, beneficial for suppressing the side reactions such as hydrogen evolution reaction and corrosion. Therefore, the stable and reversible Zn plating/stripping is achieved for the Zn anode coated by the Cu-MXene, which delivers an extended cycling life of over 1000 h with a low polarization within 120 mV at 10 mA cm⁻², and a high coulombic efficiency of over 99.6% for 1100 cycles, indicating excellent stability and reversibility of Zn stripping/plating. The practical full cell coupled with NaV₃O₈·1.5H₂O cathode also displays stable performance for 1000 cycles. The proposed Cu-MXene coating reveals a promising prospect for designing highly stable Zn anode, which can also be extended to other energy storage systems based on metal anodes.