A High‐Capacity Negative Electrode for Asymmetric Supercapacitors Based on a PMo₁₂ Coordination Polymer with Novel Water‐Assisted Proton Channels

Abstract

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.

A Fast Proton‐Induced Pseudocapacitive Supercapacitor with High Energy and Power Density

“…In order to realize the charge balance between cathode and anode during the charge and discharge process, we have determined the mass ratios of cathode to anode at ≈ 1.2. According to CV curves at different scan rates, it is found that as‐assembled asymmetric device can operate efficiently within the voltage window range of 0–1.7 V. It should be noted that the voltage window in this work is twice that of traditional symmetrical supercapacitors and single‐electrodes in sulfuric acid electrolyte, [ 17 ] which also exceeds most of reported pseudocapacitive proton supercapacitors. [ 16,41,42 ] A pair of broad redox peaks appeared in the potential window of 0.6 V–1.7 V, indicating the Faradaic feature during proton storage procedure.…”

The Role of Defects in Metal–Organic Frameworks for Nitrogen Reduction Reaction: When Defects Switch to Features

“…Polyoxometalates (POMs) have intriguing structures and also could be a resource of metals. [ 200,201 ] Therefore, POMs‐based MOFs (POMOFs) can merge the advantages of MOFs and POMs and pass them onto derivatives materials that possess high surface areas, suitable paths for the electrons and ions, and rich defects which can enhance the electrochemical properties of the reaction. [ 202 ] Recently, Wang et al.…”

Multi‐Interface‐Modulated CoS2@MoS2 Nanoarrays Derived by Predesigned Germanomolybdate Polymer Showing Ultrahighly Electrocatalytic Activity for Hydrogen Evolution Reaction in Wide pH Range

“…In the {Co 2 L 3 •6H 2 O} + , two Co 2+ metals, three L − molecules and six water molecules (Figure 1, (Figure 1, middle). [54][55][56][57] Moreover, the {Co 2 L 3 •6H 2 O} + clusters and adjacent GeMo 12 polyanions are integrated together through massive hydrogen bond interactions ( Figure S3, Supporting Information) to fabricate a 3D supermolecular structure ( Figure 1).…”