Halogens have been coupled with metal anodes in a single cell to develop novel rechargeable batteries based on extrinsic redox reactions. Since the commercial introduction of lithium‐iodine batteries ...in 1972, they have shown great potential to match the high‐rate performance, large energy density, and good safety of advanced batteries. With the development of metal anodes (e.g. Li, Zn), one of the actual challenges lies in the preparation of electrochemically active and reliable iodine‐based cathodes to prevent self‐discharge and capacity decay of the rechargeable batteries. Understanding the fundamental reactions of iodine/polyiodide and their underlying mechanisms is still highly desirable to promote the rational design of advanced cathodes for high‐performance rechargeable batteries. In this Minireview, recent advances in the development of iodine‐based cathodes to fabricate rechargeable batteries are summarized, with a special focus on the basic principles of iodine redox chemistry to correlate with structure‐function relationships.
The reversible redox reactions of iodine coupled with various anodes enable the fabrication of advanced rechargeable batteries. This Minireview summarizes the current understanding of the fundamental redox chemistry of iodine, with a special emphasis on the strategies for enhancing battery performance.
The development of low-cost efficient bifunctional oxygen electrocatalysts is of importance for optimizing the performance of metal-air batteries. By using manganese dioxide spheres as both the redox ...initiator and the self-sacrificing template for the in-situ interfacial polymerization of aniline monomers, we demonstrated a facile approach to preparing porous polyaniline spheres in the presence of phytic acid. Subsequent pyrolysis led to nitrogen and phosphorous co-doped carbon spheres (NPCSs) with highly porous structure and good bifunctional electrocatalytic activities for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Specifically, NPCSs exhibited a comparable half-wave potential (0.83 V vs. RHE) to that of commercial Pt/C, but a larger current density, for ORR and was superior to RuO2 (overpotential, 320 mV) for OER with a smaller overpotential of 310 mV. The Density Functional Theory (DFT) calculations revealed firstly that the heteroatom-doping at the edges of the porous structure plays a dominate role in achieving the high bifunctional catalytic activities. Furthermore, the bifunctional oxygen electrocatalysis enabled the fabrication of high-performance Zn-air batteries in aqueous and solid-state electrolytes, exhibiting large energy density, high power density, and good cycling stability.
The formation of highly porous carbon spheres with N, P doping at the edges enables the bifunctional oxygen electrocatalysis for fabricating rechargeable Zn-air battery with high performance. Display omitted
1.The in-situ interfacial polymerization of aniline monomers renders the preparation of highly porous polyaniline spheres by using a self-sacrificing template2.The subsequent pyrolysis leads to the formation of nitrogen and phosphorous co-doped carbon spheres (NPCSs) with good bifunctional oxygen electrocatalytic activities.3.The experimental results and DFT calculations reveal firstly that the heteroatom-doping at the edges of the porous structure play a dominate role in achieving the high bifunctional activities.4.The advanced bifunctional oxygen electrocatalyst enables the fabrication of high-performance solid-state Zn-air batteries with good flexibility.
The dendrite growth of zinc and the side reactions including hydrogen evolution often degrade performances of zinc-based batteries. These issues are closely related to the desolvation process of ...hydrated zinc ions. Here we show that the efficient regulation on the solvation structure and chemical properties of hydrated zinc ions can be achieved by adjusting the coordination micro-environment with zinc phenolsulfonate and tetrabutylammonium 4-toluenesulfonate as a family of electrolytes. The theoretical understanding and in-situ spectroscopy analysis revealed that the favorable coordination of conjugated anions involved in hydrogn bond network minimizes the activate water molecules of hydrated zinc ion, thus improving the zinc/electrolyte interface stability to suppress the dendrite growth and side reactions. With the reversibly cycling of zinc electrode over 2000 h with a low overpotential of 17.7 mV, the full battery with polyaniline cathode demonstrated the impressive cycling stability for 10000 cycles. This work provides inspiring fundamental principles to design advanced electrolytes under the dual contributions of solvation modulation and interface regulation for high-performing zinc-based batteries and others.
Graphitic carbons have been used as conductive supports for developing rechargeable batteries. However, the classic ion intercalation in graphitic carbon has yet to be coupled with extrinsic redox ...reactions to develop rechargeable batteries. Herein, we demonstrate the preparation of a free-standing, flexible nitrogen and phosphorus co-doped hierarchically porous graphitic carbon for iodine loading by pyrolysis of polyaniline coated cellulose wiper. We find that heteroatoms could provide additional defect sites for encapsulating iodine while the porous carbon skeleton facilitates redox reactions of iodine and ion intercalation. The combination of ion intercalation with redox reactions of iodine allows for developing rechargeable iodine-carbon batteries free from the unsafe lithium/sodium metals, and hence eliminates the long-standing safety issue. The unique architecture of the hierarchically porous graphitic carbon with heteroatom doping not only provides suitable spaces for both iodine encapsulation and cation intercalation but also generates efficient electronic and ionic transport pathways, thus leading to enhanced performance.Carbon-based electrodes able to intercalate Li
and Na
ions have been exploited for high performing energy storage devices. Here, the authors combine the ion intercalation properties of porous graphitic carbons with the redox chemistry of iodine to produce iodine-carbon batteries with high reversible capacities.
The rapid development of advanced energy‐storage devices requires significant improvements of the electrode performance and a detailed understanding of the fundamental energy‐storage processes. In ...this work, the self‐assembly of two‐dimensional manganese oxide nanosheets with various metal cations is introduced as a general and effective method for the incorporation of different guest cations and the formation of sandwich structures with tunable interlayer distances, leading to the formation of 3D MxMnO2 (M=Li, Na, K, Co, and Mg) cathodes. For sodium and lithium storage, these electrode materials exhibited different capacities and cycling stabilities. The efficiency of the storage process is influenced not only by the interlayer spacing but also by the interaction between the host cations and shutter ions, confirming the crucial role of the cations. These results provide promising ideas for the rational design of advanced electrodes for Li and Na storage.
Spoilt for choice: A series of three‐dimensional MxMnO2 (M=Li, Na, K, Mg, or Co) cathodes with a sandwich structure were obtained by the self‐assembly of manganese oxide nanosheets with these metal cations. The intercalated cations influence the capacity and cycling stability of these cathodes for lithium and sodium storage.
Mesoporous anatase (TiO₂) was modified with silver (Ag) nanoparticles using a photoreduction method. Performance of the resulting TiO₂–Ag nanocomposites for water purification was evaluated using ...degradation of Rhodamine B (RhB) and disinfection of Escherichia coli (E. coli) under ultraviolet (UV) irradiation. The composites with different Ag loadings were characterized using physical adsorption of nitrogen, X-ray diffraction, X-ray photoelectron spectroscopy and UV–Visible diffuse reflectance spectroscopic techniques. The results showed that metallic Ag nanoparticles were firmly immobilized on the TiO₂ surface, which improved electron-hole separation by forming the Schottky barrier at the TiO₂–Ag interface. Photocatalytic degradation of RhB and inactivation of E. coli effectively occurred in an analogical trend. The deposited Ag slightly decreased adsorption of target pollutants, but greatly increased adsorption of molecular oxygen with the latter enhancing production of reactive oxygen species (ROSs) with concomitant increase in contaminant photodegradation. The optimal Ag loadings for RhB degradation and E. coli disinfection were 0.25 wt% and 2.0 wt%, respectively. The composite photocatalysts were stable and could be used repeatedly under UV irradiation.
Silver-modified graphene oxide nanosheets (Ag-GO) were prepared and used as a novel antibacterial material, which exhibited a superior antibacterial activity towards Escherichia coli (E. coli) due to ...the synergistic effect of graphene oxide and silver nanoparticles.
Nanotubular ruthenium oxides were prepared by using manganite nanorods as a morphology sacrificial template. Experimental results showed that the template dissolved away completely during the ...formation of the ruthenium oxide nanotubes. A mechanism was proposed to interpret the formation of the ruthenium oxide nanotubes. The electrochemical capacitive properties of the ruthenium oxide nanotubes were investigated using cyclic voltammetry and charge/discharge techniques with H2SO4 and Na2SO4 solutions as the electrolytes, respectively. The specific capacitance of the nanotubular ruthenium oxide electrode was measured to be as high as 860 F/g at a current density of 500 mA/g in the H2SO4 electrolyte, which was higher than that obtained in the Na2SO4 electrolyte. In addition, the ruthenium oxide nanotubes were observed to exhibit a good capacitive retention at high current loads.
This roadmap demonstrates a series of two-dimensional nanomaterials, such as graphene, black phosphorus, oxides, layered double hydroxides, chalcogenides, bismuth-based layered compounds, MXenes, ...metal organic frameworks, covalent organic frameworks, and others, for environmental catalysis.
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Environmental catalysis has drawn a great deal of attention due to its clean ways to produce useful chemicals or carry out some chemical processes. Photocatalysis and electrocatalysis play important roles in these fields. They can decompose and remove organic pollutants from the aqueous environment, and prepare some fine chemicals. Moreover, they also can carry out some important reactions, such as O2 reduction reaction (ORR), O2 evolution reaction (OER), H2 evolution reaction (HER), CO2 reduction reaction (CO2RR), and N2 fixation (NRR). For catalytic reactions, it is the key to develop high-performance catalysts to meet the demand for targeted reactions. In recent years, two-dimensional (2D) materials have attracted great interest in environmental catalysis due to their unique layered structures, which offer us to make use of their electronic and structural characteristics. Great progress has been made so far, including graphene, black phosphorus, oxides, layered double hydroxides (LDHs), chalcogenides, bismuth-based layered compounds, MXenes, metal organic frameworks (MOFs), covalent organic frameworks (COFs), and others. This content drives us to invite many famous groups in these fields to write the roadmap on two-dimensional nanomaterials for environmental catalysis. We hope that this roadmap can give the useful guidance to researchers in future researches, and provide the research directions.
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