Preparation of α-MnO₂ Nanorods/Porous Carbon Cathode for Aqueous Zinc-ion Batteries

Abstract

Aqueous zinc-ion batteries (ZIBs) have attracted more attention as large-scale energy storage technology due to their high safety, low cost and environmental benignity. To date, numerous cathodes based on manganese dioxide, vanadium dioxide, and polyanionic compounds have been reported. Among them, Manganese oxides have the advantages of low cost, non-toxicity, abundant materials and high working voltage, have been widely explored as promising cathodes for zinc ion batteries. Among them, MnO 2 cathodes are particularly desirable candidates for commercialization owing to their tunnel structure and affordability. α-MnO 2 has (1×1) and (2×2) tunnel structures, and Zn 2＋ can rapidly inserted and deserted in the tunnel. However, the capacity of manganese dioxide is fast decaying with the cycles due to the poor conductivity of MnO 2 , which limits its electrochemical performance. Herein, α-MnO 2 nanorods are uniformly distributed on the surface of porous carbon nanosheets network (PCSs) by a simple hydrothermal/dispersion method strategy. In the α-MnO 2 /PCSs architecture, the α-MnO 2 nanorods and α-MnO 2 /PCSs composite were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), etc. The results testified that α-MnO 2 /PCSs nanorods were firmly adhered on the surface of porous carbon nanosheets, which can effectively avoid the stacking of α-MnO 2 nanorods, while the high conductive carbon network can improve the electrical conductivity of the composite. The porous network can provide effective electron transfer channels, provide stable hosts for fast Zn 2＋ extraction/insertion, and prevent the α-MnO 2 nanorods from stacking each other. Benefiting from the unique porous structure and high conductive network, the α-MnO 2 /PCSs hybrid shows high reversibility capacity, good rate performance, and outstanding cycling stability. Specifically, α-MnO 2 /PCSs exhibits high reversible capacity of 350 mAh•g -1 after 100 cycles at 0.1 A•g -1 and maintains a capacity of 160 mAh•g -1 at a high rate of 1 A•g -1 after 1000 cycles, thus making it promising cathode for the high performance ZIBs.

Coral-like carbon skeleton for aqueous zinc-ion batteries MnO2 cathode material

“…In contrast, the speci c discharge capacity of CCS@MnO 2 dropped from 170 mA h g − 1 to 70 mA h g − 1 , maintaining 58% of the capacity. The main advantages of CCS@MnO 2 electrochemical performance are its high theoretical speci c capacity, high speci c surface area, and its ability to maintain approximately 100% of the initial capacity [21,22,[30][31][32].…”

Electrolyte Optimization Strategy: Enabling Stable and Eco-Friendly Zinc Adaptive Interfacial Layer in Zinc Ion Batteries

“…Several improvement methods have been proposed to address the various challenges faced by zinc-ion batteries, such as electrolyte optimization, negative electrode modification, and positive electrode structural design [ 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 ]. Among these methods, electrolyte optimization through the addition of additives has been proven to be a simple, effective, and cost-efficient approach [ 26 , 27 ].…”

Recent development in addressing challenges and implementing strategies for manganese dioxide cathodes in aqueous zinc ion batteries

“…In addition, aqueous electrolytes possess superior ionic conductivity compared to organic electrolytes, enhancing the battery kinetics, including rate capability and charging/discharging capabilities [30] . A wide class of materials, e.g., Prussian blue analogs (PBAs), vanadium, nickel (Ni)-based, cobalt (Co)-based, and manganese (Mn)-based compounds, can be coupled with Zn anodes to construct AZIBs [31][32][33][34][35][36][37][38][39] [Figure 1A]. The electrochemical characteristics and reaction processes of the diverse AZIBs are outlined in Table 2 below.…”