Abstract:Ion diffusion efficiency at the solid-liquid interface is an important factor for energy storage and adsorption from aqueous solution. Although K Mn O (KMO) exhibits efficient ion diffusion and ion-exchange capacities, due to its high interlayer space of 0.70 nm, how to enhance its mass transfer performance is still an issue. Herein, novel layered KMO/reduced graphene oxide (RGO) nanocomposites are fabricated through the anchoring of KMO nanoplates on RGO with a mild solution process. The face-to-face structur… Show more
“…Meanwhile, abundant mesopores with a relatively narrow pore-size distribution of ~ 8 nm provide a large number of active sites for storage of zinc ions and enhance the contact area of the active material with the electrolyte, promoting the transport and diffusion of zinc ions [ 41 , 48 , 49 ]. In addition, the presence of these mesopores is favorable for regulating the volume change caused by the insertion/extraction of zinc ions during the discharge/charge process, ensuring a satisfactory cyclability and a high specific capacity [ 3 , 50 ]. Fig.…”
HIGHLIGHTS• A layered sodium-ion/crystal water co-intercalated Na 0.55 Mn 2 O 4 ·0.57H 2 O (NMOH) cathode is synthesized successfully with a selectively etching method for zinc-ion batteries.• A displacement/intercalation mechanism is confirmed in the Mn-based cathode for the first time.• The NMOH cathode delivers a competitive reversible capacity of 201.6 mA h g −1 at 500 mA g −1 after 400 cycles.ABSTRACT Mn-based rechargeable aqueous zinc-ion batteries (ZIBs) are highly promising because of their high operating voltages, attractive energy densities, and eco-friendliness. However, the electrochemical performances of Mn-based cathodes usually suffer from their serious structure transformation upon charge/discharge cycling.Herein, we report a layered sodium-ion/crystal water co-intercalated Birnessite cathode with the formula of Na 0.55 Mn 2 O 4 ·0.57H 2 O (NMOH) for high-performance aqueous ZIBs. A displacement/intercalation electrochemical mechanism was confirmed in the Mn-based cathode for the first time. Na + and crystal water enlarge the interlayer distance to enhance the insertion of Zn 2+ , and some sodium ions are replaced with Zn 2+ in the first cycle to further stabilize the layered structure for subsequent reversible Zn 2+ /H + insertion/extraction, resulting in exceptional specific capacities and satisfactory structural stabilities. Additionally, a pseudo-capacitance derived from the surface-adsorbed Na + also contributes to the electrochemical performances. The NMOH cathode not only delivers high reversible capacities of 389.8 and 87.1 mA h g −1 at current densities of 200 and 1500 mA g −1 , respectively, but also maintains a good long-cycling performance of 201.6 mA h g −1 at a high current density of 500 mA g −1 after 400 cycles, which makes the NMOH cathode competitive for practical applications.Zinc sulfate (ZnSO 4 ·H 2 O, 99.9%), sodium sulfate (Na 2 SO 4 , 99.9%), and manganese sulfate (MnSO 4 ·H 2 O, 99.9%) were purchased from Aladdin (China). Sodium silicate Nano-Micro Lett.
“…Meanwhile, abundant mesopores with a relatively narrow pore-size distribution of ~ 8 nm provide a large number of active sites for storage of zinc ions and enhance the contact area of the active material with the electrolyte, promoting the transport and diffusion of zinc ions [ 41 , 48 , 49 ]. In addition, the presence of these mesopores is favorable for regulating the volume change caused by the insertion/extraction of zinc ions during the discharge/charge process, ensuring a satisfactory cyclability and a high specific capacity [ 3 , 50 ]. Fig.…”
HIGHLIGHTS• A layered sodium-ion/crystal water co-intercalated Na 0.55 Mn 2 O 4 ·0.57H 2 O (NMOH) cathode is synthesized successfully with a selectively etching method for zinc-ion batteries.• A displacement/intercalation mechanism is confirmed in the Mn-based cathode for the first time.• The NMOH cathode delivers a competitive reversible capacity of 201.6 mA h g −1 at 500 mA g −1 after 400 cycles.ABSTRACT Mn-based rechargeable aqueous zinc-ion batteries (ZIBs) are highly promising because of their high operating voltages, attractive energy densities, and eco-friendliness. However, the electrochemical performances of Mn-based cathodes usually suffer from their serious structure transformation upon charge/discharge cycling.Herein, we report a layered sodium-ion/crystal water co-intercalated Birnessite cathode with the formula of Na 0.55 Mn 2 O 4 ·0.57H 2 O (NMOH) for high-performance aqueous ZIBs. A displacement/intercalation electrochemical mechanism was confirmed in the Mn-based cathode for the first time. Na + and crystal water enlarge the interlayer distance to enhance the insertion of Zn 2+ , and some sodium ions are replaced with Zn 2+ in the first cycle to further stabilize the layered structure for subsequent reversible Zn 2+ /H + insertion/extraction, resulting in exceptional specific capacities and satisfactory structural stabilities. Additionally, a pseudo-capacitance derived from the surface-adsorbed Na + also contributes to the electrochemical performances. The NMOH cathode not only delivers high reversible capacities of 389.8 and 87.1 mA h g −1 at current densities of 200 and 1500 mA g −1 , respectively, but also maintains a good long-cycling performance of 201.6 mA h g −1 at a high current density of 500 mA g −1 after 400 cycles, which makes the NMOH cathode competitive for practical applications.Zinc sulfate (ZnSO 4 ·H 2 O, 99.9%), sodium sulfate (Na 2 SO 4 , 99.9%), and manganese sulfate (MnSO 4 ·H 2 O, 99.9%) were purchased from Aladdin (China). Sodium silicate Nano-Micro Lett.
“…Their high reaction activity endows them with relatively good electrochemical performance, however the relatively low conductivity hampers their efficiency. Layered materials such as TMOs, TMDs, phosphorenes, metal carbides, metal sulfides or silicenes can be combined with RGO/graphene, [65][66][67][68][69][70][156][157][158][159][160][161][162][163][164][165][166][167][168] doped RGO/graphene, [71,72,169,170] CNT, [73][74][75][76]171] conductive carbon, [77][78][79][80][172][173][174][175][176][177] carbon nanofibers, [81] carbon nanoboxes, [82] metals, [178] or conducting polymers, [179] generating hybrid electrode materials for LIBs with excellent performance. [54][55][56][57]…”
Section: Lithium-ion Batteriesmentioning
confidence: 99%
“…Therefore, rationally introducing ad hoc functional nanomaterials into single component 2D system may be a route to improve the performance of energy storage devices in terms of capacity, efficiency, activity, and stability, which may origin from the synergetic effect. Layered materials such as TMOs, TMDs, phosphorenes, metal carbides, metal sulfides or silicenes can be combined with RGO/graphene, doped RGO/graphene, CNT, conductive carbon, carbon nanofibers, carbon nanoboxes, metals, or conducting polymers, generating hybrid electrode materials for LIBs with excellent performance. Dou and co‐workers fabricated an atomic layer‐by‐layer structure of Co 3 O 4 /graphene and used it as an anode for LIBs .…”
as supercapacitors and batteries, with high power/energy densities, are expected to play essential roles in our daily life as the dominant power sources for portable consumer electronics (e.g., smartphones, tablets, notebook PCs and camcorders), hybrid electric/plug-in-hybrid vehicles and smart grids. [1][2][3][4][5][6] The recently increased research efforts on 2D materials, i.e., graphene and its analogues, is to a great extent the result of the promise that they hold for technological applications including electronic devices, sensors, catalysts, energy conversion and storage devices, etc., by taking full advantage of their outstanding electrical, optical, chemical, and thermal properties. [7][8][9][10][11][12][13][14] Beyond graphene, other layered materials possessing various elemental compositions and different crystallographic structures, offer a broad portfolio of material's solutions with tunable chemical and physical properties for application as high-performance active components, which can operate as electrode materials for high-performance electrochemical energy storage devices. [4,15,16] Although graphene-based nanomaterials have demonstrated outstanding performance as electrodes in energy storage devices, new alternative nanomaterials should also be developed in order to further improve the electrochemical performance. Other 2D materials as graphene analogues (GAs) are expected to have broad implications in next generation of clean, efficient, and renewable energy systems. Layered materials of GAs refer to layered materials having similar structure as graphene, with planar topology and ultrathin thickness (single to few atomic layers). Typical GAs for energy storage include transition metal dichalcogenides (TMDs), transition metal oxides (TMOs)/ hydroxides (TMHs), metal sulfides, phosphorenes, MXenes, silicences, etc. (Figure 1). [17] Due to their thickness on the atomic scale, their inherent properties differ from those of their bulk lamellar systems. In particular, the quantum confinement of electrons in the 2D plane imparts them with unprecedented electrical and electronic characteristics ( Table 1). [18][19][20][21][22][23][24][25][26] Moreover, it is well known that the delivered specific capacity of electrode materials is closely related with the reaction kinetics during the charging/discharging process. [3] In view of their high surfaceto-volume ratio, GAs offer high specific surface areas (Table 1) to enable full utilization of all available sites of active electrode materials. [27][28][29][30] As a result, the exposed contact area is significantly enhanced between the electrodes and electrolytes, and also the paths for transport of charges are largely shortened.Energy crisis is one of the most urgent and critical issues in our modern society. Currently, there is an increasing demand for efficient, low-cost, lightweight, flexible and environmentally benign, small-, medium-, and large-scale energy storage devices, which can be used to power smart grids, portable electronic devices, and elect...
“…The discharge capacity of the first lap is as high as 739 mAh g À 1 , and after 100 cycles, it can still maintain 664 mAh g À 1 . [21] Rodney Chua et al used polyvinylpyrrolidone-assisted sol-gel method to prepare Na 4 Mn 9 O 18 template, and the initial discharge capacity was 77.2 mAh g À 1 at a voltage range of 0.3-1.0 V and a current density of 100 mA g À 1 . [22] In order to improve the cycling stability of Na 0.67 MnO 2 material, Billaud Juliette et al utilized a small amount of magnesium ion doping for smoothing the charge/discharge curve, which effectively improved the cycling stability.…”
In recent times, the research on cathode materials for aqueous rechargeable magnesium ion battery has gained significant attention. The focus is on enhancing high‐rate performance and cycle stability, which has become the primary research goal. Manganese oxide and its derived Na‐Mn‐O system have been considered as one of the most promising electrode materials due to its low cost, non‐toxicity and stable spatial structure. This work uses hydrothermal method to prepare titanium gradient doped nano sodium manganese oxides, and uses freeze‐drying technology to prepare magnesium ion battery cathode materials with high tap density. At the initial current density of 50 mA g‐1, the NMTO‐5 material exhibits a high reversible capacity of 231.0 mAh g‐1, even at a current density of 1000 mA g‐1, there is still 122.1 mAh g‐1. It is worth noting that after 180 cycles of charging and discharging at a gradually increasing current density such as 50‐1000 mA g‐1, it can still return to the original level after returning to 50 mA g‐1. Excellent electrochemical performance and capacity stability show that NMTO‐5 material is a promising electrode material.
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