cell design have presented numerous safety hazards and economic challenges, [3][4][5] which make LIBs less suitable for largescale applications. Compared with organic LIBs, aqueous rechargeable Zn-ion batteries (ZIBs) equipped with nonflammable and highly ion conductive aqueous electrolytes are highly desirable. They benefit from a high theoretical capacity (a gravimetric capacity of 820 mAh g −1 and a volumetric capacity of 5855 mAh cm −3 ) and a low plating/stripping potential (−0.76 V vs standard hydrogen electrode), as well as a high natural abundance of metallic Zn. [6][7][8] Unfortunately, the uncontrolled formation of dendrites, undesired side reactions (e.g., corrosion, hydrogen evolution, and by-product formation), and huge volume variation during repeated Zn deposition-dissolution processes of the host-less metallic Zn anode not only limit the efficiency of plating and stripping, but also result in a remarkably short lifespan, or even internal short-circuiting. [9][10][11] In order to address the issues mentioned above, several strategies have been proposed to regulate the Zn plating/stripping behaviors for stable Zn metal batteries, including surface modification, [12][13][14] electrolyte optimization, [15][16][17] and electrode structural design. [18][19][20] For instance, an ultrathin MXene layer and glucose have been used as an artificial layer and a multifunctional electrolyte additive to stabilize Zn metal anodes, Aqueous Zn metal batteries have attracted much attention due to their high intrinsic capacity, high safety, and low cost. Nevertheless, uncontrollable dendrite growth and adverse side reactions of Zn anodes seriously hinder their further application. Herein, a three-dimensional (3D) porous graphene-carbon nanotubes scaffold decorated with metal-organic framework derived ZnO/C nanoparticles (3D-ZGC) is fabricated as the host for dendrite-free Zn-metal composite anodes. The zincophilic ZnO/C nanoparticles act as preferred deposition sites with low nucleation barriers to induce homogeneous Zn deposition. The mechanically robust 3D scaffold with high conductivity not only suppresses the formation of dendritic Zn by reducing the local current density and homogenizing Zn 2+ ion flux, but also inhibits volume changes during the long-term plating/stripping process. As a result, the 3D-ZGC composite anodes afford unprecedented Zn plating-stripping stability at an ultrahigh current density of 20 mA cm -2 for 1500 cycles with low overpotential (<65 mV) when used in a symmetric cell. When coupled with MnO 2 cathodes, the assembled Zn@3D-ZGC//MnO 2 full batteries deliver an enhanced cycling stability for up to 6000 cycles at 2000 mA g -1 , demonstrating the potential of the 3D-ZGC composite anode for advanced Zn metal batteries.

The development of a negative electrode for supercapacitors is a critical challenge for the next-generation of energy-storage devices. Herein, we describe two new electrodes formed by the coordination polymers [Ni(itmb) 4 (HPMo 12 O 40 )]•2H 2 O (1) and [Zn(itmb) 3 (H 2 O)(HPMo 12 O 40 )]•4H 2 O (2) (itmb = 1-(imidazo-1-ly)-4-(1,2,4-triazol-1-ylmethyl)benzene), synthesized by a simple hydrothermal method. Compounds 1 and 2 show high capacitances of 477.9 and 890.2 F g -1 , respectively. An asymmetric supercapacitor device assembled using 2 which has novel water-assisted proton channels as negative electrode and active carbon as positive electrode shows ultrahigh energy density and power density of 23.4 W h kg -1 and 3864.4 W kg -1 , respectively. Moreover, the ability to feed a red LED also demonstrates the This article is protected by copyright. All rights reserved. feasibility for practical use. Our results allow a better elucidation of the storage mechanism in polyoxometalate-based coordination polymers and provide a promising direction for exploring novel negative materials for new-generation high-performance supercapacitors.

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