Metal–organic frameworks (MOFs) with intrinsically porous structures and well‐dispersed metal sites are promising candidates for electrocatalysis; however, the catalytic efficiencies of most MOFs are ...significantly limited by their impertinent adsorption/desorption energy of intermediates formed during electrocatalysis and very low electrical conductivity. Herein, Co is introduced into conductive Cu‐catecholate (Cu‐CAT) nanorod arrays directly grown on a flexible carbon cloth for hydrogen evolution reaction (HER). Electrochemical results show that the Co‐incorporated Cu‐CAT nanorod arrays only need 52 and 143 mV overpotentials to drive a current density of 10 mA cm−2 in alkaline and neutral media for HER, respectively, much lower than most of the reported non‐noble metal‐based electrocatalysts and comparable to the benchmark Pt/C electrocatalyst. Density functional theory calculations show that the introduction of Co can optimize the adsorption energy of hydrogen (ΔGH*) of Cu sites, almost close to that of Pt (111). Furthermore, the adsorption energy of water (ΔEH2O) of Co sites in the CuCo‐CAT is significantly lower than that of Cu sites upon coupling Cu with Co, effectively accelerating the Volmer step in the HER process. The findings, synergistic effect of bimetals, open a new avenue for the rational design of highly efficient MOF‐based electrocatalysts.
Conductive bimetal‐based catecholate (CAT) nanorod arrays show excellent hydrogen evolution reaction activities in both alkaline and neutral electrolyte, comparable to that of the benchmark Pt/C. Density functional theory calculations demonstrate that the incorporation of Co not only optimizes the ΔGH* and the adsorption energy of water (ΔEH2O) of Cu‐CAT, but also increases the electrical conductivity of Cu‐CAT.
Rechargeable sodium‐ion batteries (SIBs), as the most promising alternative to commercial lithium‐ion batteries, have received tremendous attention during the last decade. Among all the anode ...materials for SIBs, metal sulfides/selenides (MXs) have shown inspiring results because of their versatile material species and high theoretical capacity. They suffer from large volume expansion, however, which leads to bad cycling performance. Thus, methods such as carbon modification, nanosize design, electrolyte optimization, and cut‐off voltage control are used to obtain enhanced performance. Here, recent progress on MXs is summarized in terms of arranging the crystal structure, synthesis methods, electrochemical performance, mechanisms, and kinetics. Challenges are presented and effective ways to solve the problems are proposed, and a perspective for future material design is also given. It is hoped that light is shed on the development of MXs to help finally find applications for next‐generation rechargeable batteries.
Metal sulfides and metal selenides have shown great progress as anode materials for sodium‐ion batteries because of their versatile material species, easily controlled morphology, and high theoretical specific capacity. Their advances and challenges are summarized, showing their importance for next‐generation energy storage and conversion devices.
Sodium‐ion batteries (SIBs) show tremendous potential for large‐scale energy storage systems due to the high abundance of sodium resources and potentially low cost. Among the discovered anode ...materials for SIBs, metal selenides with large theoretical capacities are considered as a promising candidate. Nevertheless, metal selenide‐based anodes are trapped by poor ionic/electronic conductivity, low initial Coulombic efficiency, and drastic volume changes during the (de)sodiation process. Herein, the differences in sodium‐storage mechanisms of different metal selenides are first analyzed. Subsequently, the specific challenges and corresponding modification strategies (such as nanostructure design, carbon modification, potential window regulation, electrolyte optimization, and constructing heterostructures) for metal selenides as SIB anodes are discussed in detail, and recent advances are also presented. Finally, the potential research directions of metal selenides in SIBs are comprehensively reviewed. It is believed that this review can provide constructive comments on the optimization and large‐scale application of high‐performance metal selenide‐based anode for SIBs.
Recently, sodium‐ion batteries have attracted extensive attentions due to the high abundance of sodium resources and low cost. In this review, the recent progress and the strategies on optimizing the metal selenide‐based anodes for high‐performance sodium‐ion batteries are systematically summarized.
Since their successful commercialization in 1990s, lithium‐ion batteries (LIBs) have been widely applied in portable digital products. The energy density and power density of LIBs are inadequate, ...however, to satisfy the continuous growth in demand. Considering the cost distribution in battery system, it is essential to explore cathode/anode materials with excellent rate capability and long cycle life. Nanometer‐sized electrode materials could quickly take up and store numerous Li+ ions, afforded by short diffusion channels and large surface area. Unfortunately, low thermodynamic stability of nanoparticles results in electrochemical agglomeration and raises the risk of side reactions on electrolyte. Thus, micro/nano and hetero/hierarchical structures, characterized by ordered assembly of different sizes, phases, and/or pores, have been developed, which enable us to effectively improve the utilization, reaction kinetics, and structural stability of electrode materials. This review summarizes the recent efforts on electrode materials with hierarchical structures, and discusses the effects of hierarchical structures on electrochemical performance in detail. Multidimensional self‐assembled structures can achieve integration of the advantages of materials with different sizes. Core/yolk–shell structures provide synergistic effects between the shell and the core/yolk. Porous structures with macro‐, meso‐, and micropores can accommodate volume expansion and facilitate electrolyte infiltration.
Recent developments on electrode materials with hierarchical structure are summarized and the effects of hierarchical structures on electrochemical performance are discussed. To deal with the intrinsic defects of the materials themselves, several common structures are proposed to address the problems of cathode and anode materials, such as multidimensional self‐assembled structures, core/yolk–shell structures, and porous structures.
The development of large‐scale energy storage systems (ESSs) aimed at application in renewable electricity sources and in smart grids is expected to address energy shortage and environmental issues. ...Sodium‐ion batteries (SIBs) exhibit remarkable potential for large‐scale ESSs because of the high richness and accessibility of sodium reserves. Using low‐cost and abundant elements in cathodes with long cycling stability is preferable for lowering expenses on cathodes. Many investigated cathodes for SIBs are dogged by structural and morphology changes, unstable interphases between the cathode and the electrolyte, and air sensitivity, causing unsatisfactory cycling performance. Therefore, understanding the mechanism of capacity degeneration in depth and developing precise solutions are critical for designing low‐cost cathodes that are highly stable under cycling. Herein, recent progress in long‐cycle‐life and low‐cost cathodes for SIBs is focused on, and a comprehensive discussion of the key points in SIBs toward large‐scale applications is provided. The roots of the unstable cycling performance of low‐cost cathodes are discussed. Also, effective strategies are summarized from the recent progress on long‐cycle‐life and low‐cost cathodes. This review is expected to encourage deeper investigation of long‐lifespan cathodes for SIBs, particularly for potential large‐scale industrialization.
Understanding the origins of capacity degeneration and developing precise solutions are critical for designing low‐cost cathodes with long cycling life for sodium‐ion batteries. The roots of the unstable cycling performance of low‐cost cathodes are discussed. Effective strategies are summarized from the recent progress on long‐cycle‐life and low‐cost cathodes.
With the unprecedentedly increasing demand for renewable and clean energy sources, the sodium‐ion battery (SIB) is emerging as an alternative or complementary energy storage candidate to the present ...commercial lithium‐ion battery due to the abundance and low cost of sodium resources. Layered transition metal oxides and Prussian blue analogs are reviewed in terms of their commercial potential as cathode materials for SIBs. The recent progress in research on their half cells and full cells for the ultimate application in SIBs are summarized. In addition, their electrochemical performance, suitability for scaling up, cost, and environmental concerns are compared in detail with a brief outlook on future prospects. It is anticipated that this review will inspire further development of layered transition metal oxides and Prussian blue analogs for SIBs, especially for their emerging commercialization.
Layered transition metal oxides and Prussian blue analogs are reviewed in terms of their commercial potential as cathode materials for sodium‐ion batteries. Recent research progresses, and their electrochemical performance, scale‐up availability, cost, and environmental concerns are discussed in detail and prospected. It is anticipated that this review could inspire the development and provide guidance for their emerging commercialization.
High‐performance catalysts are required in various energy storage and conversion systems. In this work, hierarchical Ni‐Fe‐Mo trimetal nitride nanotubes (NTs) as highly efficient, low‐cost, robustly ...stable, multifunctional catalysts through room‐temperature Fe incorporation and subsequent thermal treatment for full water splitting and Zn‐air batteries are fabricated. The two‐electrode electrolyzer assembled from the NTs delivers a current density of 10 mA cm−2 at 1.513 V, outperforming the precious metal IrO2|Pt couple and state‐of‐the‐art bifunctional catalysts. Furthermore, two all‐solid‐state Zn‐air batteries with the hierarchical NT air cathode in series can power 55 red light‐emitting diodes with excellent operation stability, at the same time as the electrolyzer based on the hierarchical NTs.
An alkaline electrolyzer and zinc‐air battery assembled with trifunctional Ni‐Fe‐Mo nitride nanotubes exhibits excellent electrochemical properties. The electrolyzer shows remarkable activity with a current density of 10 mA cm−2 at a voltage of 1.513 V, superior to the Pt and IrO2 couple, and can be self‐powered by the Zn‐air battery with the nanotubes as air‐cathode.
Most of the cathode materials for potassium ion batteries (PIBs) suffer from poor structural stability due to the large ionic radius of K+, resulting in poor cycling stability. Here we report a ...low‐strain potassium‐rich K1.84NiFe(CN)60.88⋅0.49 H2O (KNiHCF) as a cathode material for PIBs. The as‐prepared KNiHCF cathode can deliver reversible discharge capacity of 62.8 mAh g−1 at 100 mA g−1, with a high discharge voltage of 3.82 V. It can also achieve a superior rate performance of 45.8 mAh g−1 at 5000 mA g−1, with a capacity retention of 88.6 % after 100 cycles. The superior performance of KNiHCF cathode results from low‐strain de‐/intercalation mechanism, intrinsic semiconductor property and low potassium diffusion energy barrier. The high power density and long‐term stability of KNiHCF//graphite full cell confirmed the feasibility of K‐rich KNiHCF cathode in PIBs. This work provides guidance to develop Prussian blue analogues as cathode materials for PIBs.
A low‐strain potassium‐rich K1.84NiFe(CN)60.88⋅0.49 H2O (KNiHCF) was prepared by a facile co‐precipitation method. The KNiHCF//graphite full cell exhibits high rate performance, superior cycling stability, and high power density. This work would offer an insight into design of the low‐strain cathode materials for PIBs.
Recently, room‐temperature stationary sodium‐ion batteries (SIBs) have received extensive investigations for large‐scale energy storage systems (EESs) and smart grids due to the huge natural ...abundance and low cost of sodium. The SIBs share a similar “rocking‐chair” sodium storage mechanism with lithium‐ion batteries; thus, selecting appropriate electrodes with a low cost, satisfactory electrochemical performance, and high reliability is the key point for the development for SIBs. On the other hand, the carefully chosen elements in the electrodes also largely determine the cost of SIBs. Therefore, earth‐abundant‐metal‐based compounds are ideal candidates for reducing the cost of electrodes. Among all the high‐abundance and low‐cost metal elements, cathodes containing iron and/or manganese are the most representative ones that have attracted numerous studies up till now. Herein, recent advances on both iron‐ and manganese‐based cathodes of various types, such as polyanionic, layered oxide, MXene, and spinel, are highlighted. The structure–function property for the iron‐ and manganese‐based compounds is summarized and analyzed in detail. With the participation of iron and manganese in sodium‐based cathode materials, real applications of room‐temperature SIBs in large‐scale EESs will be greatly promoted and accelerated in the near future.
State‐of‐the‐art high‐abundance and low‐cost metal‐based cathode materials for sodium‐ion batteries are comprehensively summarized and analyzed, providing a step toward the real‐life, commercial application of sodium‐ion batteries. Constructive suggestions and guidance are provided and future prospects regarding this promising field are discussed.
Next‐generation sodium‐ion batteries (SIBs) and potassium‐ion batteries (PIBs) are considered to be promising alternatives to replace current lithium‐ion batteries due to the high abundance of sodium ...and potassium resources. New energetic vanadium‐based compounds that undergoes multielectron reactions and demonstrate good sodium/potassium storage capability, provide new solutions for high‐performance SIBs/PIBs in terms of high energy/power density and long‐time cyclability. So far, desirable rich redox centers (V2+‐V5+), consolidated frameworks, and the high theoretical capacities of vanadium‐based compounds have been widely explored for practical applications. Rational materials design utilizing vanadium multiredox centers and the fundamental understanding of their charge‐transfer processes and mechanisms are critical in the development of high‐performance battery systems. The scientific importance and basic design strategies for high performance V‐based anode/cathode materials, structure‐function properties and state‐of‐the‐art understanding of V‐based electrode materials are herein classified and highlighted alongside their design strategies. The important role of the valence electron layer of vanadium, and the scientific advances of vanadium partitions in other electrochemical behaviors are also summarized in detail. Finally, relevant strategies and perspectives discussed in this review provide practical guidance to explore the undiscovered potentials of multi‐electron reaction relationships of not only V‐based composites, but also other types of electrode materials.
This review highlights the scientific importance, recent advances, and future perspectives on developing electrochemically active multielectron reactions of vanadium‐based electrodes for high‐performance sodium/potassium‐ion batteries.
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