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High-quality Co2P nanodendrites are one-step prepared using a molten-salt-assisted synthesis method, which avoids the release of highly toxic phosphine and the use of flammable organic phosphorus sources. Electrochemical measurements reveal that Co2P nanodendrites can be used as an efficient electrocatalyst for ammonia (NH3) synthesis from the nitrate reduction reaction (NO3−RR) in a neutral electrolyte. At an applied potential of −0.6 V vs. reversible hydrogen electrode, Co2P nanodendrites can operate stably for 10 continuous cycles, and the average faradaic efficiency and yield rate of ammonia generation are 88.57% and 5.11 mg cm−2 h−1, respectively. Thus, the present results will provide new insights into the synthesis of phosphides and the development of NO3−RR catalysts. [ABSTRACT FROM AUTHOR]

Covalent organic frameworks (COFs), thanks to their adjustable porous structure and abundant build‐in functional motifs, have been recently regarded as promising electrode materials for a variety of batteries. There still remain grand opportunities to further utilizing their merits for developing advanced COFs‐based batteries. In this paper, we propose a hybrid acid/alkali all‐COFs battery by coupling pyrene‐4,5,9,10‐tetraone based COF cathode with anthraquinone based COF anode. In such a hybrid acid/alkali all‐COFs battery, the cathodic COF favorably works in acid with a relatively positive potential, while the anodic COF preferably runs in alkali with a relatively negative potential. It thus can deliver a decently high discharge capacity of 92.97 mAh g−1 with a wide voltage window of 2.0 V, and exhibit high energy density of 74.2 Wh kg−1 along with a considerable cyclic stability over 300 cycles. The development of the proof‐of‐concept all‐COFs battery may drive forward the improvement of newly cost‐effective and performance‐reliable energy storage devices. [ABSTRACT FROM AUTHOR]

Zn ion energy storage devices have received widespread attention because of their high safety, environmental friendliness, low cost, and high energy density. However, Zn metal anodes usually suffer from disadvantages such as dendrite growth, low coulombic efficiency, and volume expansion during plating/stripping, which severely hampers the practical applications. Here, we construct 3D Zn frameworks by exploring different conductive hosts and modify 3D hosts by plating Sn to suppress Zn dendrites and side reactions. The electrode which optimized by electroplating Zn after chemically plating Sn on Cu foam (Sn−Cu foam@Zn) exhibits stable polarization voltage distribution and almost 100% coulombic efficiency over 200 cycles of Zn plating/stripping. Furthermore, when pairing with V2O5 cathode, the full cell showed fast reaction kinetics and a capacity of 113 mAh g−1 after 1000 cycles at a current density of 1 A g−1, which is 90.4% of the initial capacity. This work provides a new strategy for the development of high‐performance Zn anodes. [ABSTRACT FROM AUTHOR]

The development of high‐efficient electrocatalysts with low applied voltage and robust stability is of great importance for electrolysis of water. In this work, a bifunctional electrode has been developed by growing palladium‐modified FeCoS2 nanosheet arrays on Ni foam (Pd‐FeCoS2 NAs/NF), which can serve as anode and cathode for alkaline water splitting with high activities and ultra‐strong durability. The Pd‐FeCoS2 NAs/NF shows overpotentials of 130 mV for hydrogen evolution reaction (HER) and 202 mV for alkaline oxygen evolution reaction (OER) at 10 mA cm−2. The alkaline electrolyzer is built by employing Pd‐FeCoS2 NAs/NF as cathode and anode, delivering a current density of 50 mA cm−2 at 1.59 V. Moreover, the electrolyzer can run stably for 600 h with negligible decline. [ABSTRACT FROM AUTHOR]

Sodium based dual‐ion battery (SDIB) has been regarded as one of the promising batteries technologies thanks to its high working voltage and natural abundance of sodium source, its practical application yet faces critical issues of low capacity and sluggish kinetics of intercalation‐type graphite anode. Here, a tubular nanohybrid composed of building blocks of carbon‐film wrapped WS2 nanosheets on carbon nanotube (WS2/C@CNTs) was reported. The expanded (002) interlayer and dual‐carbon confined structure endowed WS2 nanosheets with fast charge transportation and excellent structural stability, and thus WS2/C@CNTs showed highly attractive electrochemical properties for Na+ storage with high reversible capacity, fast kinetic, and robust durability. The full sodium‐based dual ion batteries by coupling WS2/C@CNTs anode with graphite cathode full cell presented a high reversible capacity (210 mAh g−1 at 0.1 A g−1), and excellent rate performance with a high capacity of 137 mAh g−1 at 5.0 A g−1. [ABSTRACT FROM AUTHOR]

Aqueous Zn‐based batteries hold multiple advantages of eco‐friendliness, easy accessibility, high safety, easy fabrication, and fast kinetics, while their widespread applications have been greatly limited by the relatively narrow thermodynamically stable potential windows (i. e. 1.23 V) of water and the mismatched pH conditions between cathode and anode, which presents challenges regarding how to maximize the output voltage and the energy density. Recently, aqueous OH−/H+ dual‐ion Zn‐based batteries (OH−/H+‐DIZBs), where the Zn anode reacts with hydroxide ions (OH−) in alkaline electrolyte while hydrogen ions (H+) are involved in the cathode reaction in the acidic electrolyte, have been reported to be capable of broadening the working voltage and improving the energy density, which offers practical feasibility toward overcoming the above limitations. This Review thus takes this chance to investigate the recent progress on aqueous OH−/H+‐DIZBs. First, the concept and the history of such OH−/H+‐DIZBs are introduced, and then special emphasis is put on the working mechanisms, the progress of the development of new batteries, and how the electrolytes improve their performance. Finally, the challenges and opportunities in this field are discussed. [ABSTRACT FROM AUTHOR]

The development of precious‐metal alternative electrocatalysts for oxygen reduction reaction (ORR) is highly desired for a variety of fuel cells, and single atom catalysts (SACs) have been envisaged to be the promising choice. However, there remains challenges in the synthesis of high metal loading SACs (>5 wt.%), thus limiting their electrocatalytic performance. Herein, a facile self‐sacrificing template strategy is developed for fabricating Co single atoms along with Co atomic clusters co‐anchored on porous‐rich nitrogen‐doped graphene (Co SAs/AC@NG), which is implemented by the pyrolysis of dicyandiamide with the formation of layered g‐C3N4 as sacrificed templates, providing rich anchoring sites to achieve high Co loading up to 14.0 wt.% in Co SAs/AC@NG. Experiments combined with density functional theory calculations reveal that the co‐existence of Co single atoms and clusters with underlying nitrogen doped carbon in the optimized Co40SAs/AC@NG synergistically contributes to the enhanced electrocatalysis for ORR, which outperforms the state‐of‐the‐art Pt/C catalysts with presenting a high half‐wave potential (E1/2 = 0.890 V) and robust long‐term stability. Moreover, the Co40SAs/AC@NG presents excellent performance in Zn–air battery with a high‐peak power density (221 mW cm−2) and strong cycling stability, demonstrating great potential for energy storage applications. [ABSTRACT FROM AUTHOR]

In this study, we used effective and one-pot Heck coupling reactions under moderate reaction conditions to construct two new hybrid porous polymers (named OVS-P-TPA and OVS-P-F HPPs) with high yield, based on silsesquioxane cage nanoparticles through the reaction of octavinylsilsesquioxane (OVS) with different brominated pyrene (P-Br4), triphenylamine (TPA-Br3), and fluorene (F-Br2) as co-monomer units. The successful syntheses of both OVS-HPPs were tested using various instruments, such as X-ray photoelectron (XPS), solid-state 13C NMR, and Fourier transform infrared spectroscopy (FTIR) analyses. All spectroscopic data confirmed the successful incorporation and linkage of P, TPA, and F units into the POSS cage in order to form porous OVS-HPP materials. In addition, the thermogravimetric analysis (TGA) and N2 adsorption analyses revealed the thermal stabilities of OVS-P-F HPP (Td10 = 444 °C; char yield: 79 wt%), with a significant specific surface area of 375 m2 g–1 and a large pore volume of 0.69 cm3 g–1. According to electrochemical three-electrode performance, the OVS-P-F HPP precursor displayed superior capacitances of 292 F g−1 with a capacity retention of 99.8% compared to OVS-P-TPA HPP material. Interestingly, the OVS-P-TPA HPP showed a promising HER value of 701.9 µmol g−1 h−1, which is more than 12 times higher than that of OVS-P-F HPP (56.6 µmol g−1 h−1), based on photocatalytic experimental results. [ABSTRACT FROM AUTHOR]

Transition metal dichalcogenides with high theoretical capacity usually suffer from poor intrinsic electronic conductivity and drastic volumetric change upon cycling, degrading their attractiveness for electrochemical high‐power and long‐term applications. Herein, a high‐efficiency and extensible synthetic strategy for in situ encapsulating nanostructured SnSe0.5S0.5 into N‐doped graphene (SnSe0.5S0.5 @ NG) by robust interfacial CSeSn bonds with formation of 3D porous network nanohybrids, is reported. Systematic electrochemical studies indicate that interface and structure engineering on SnSe0.5S0.5, including defects implantation, chemical bonding interaction, and nanospace confinement design, endow it with robust structural stability, ultrafast Na+ storage kinetics, and highly reversible redox reaction. In addition, the introduction of foreign Se ligand not only facilitates the transport of electrons/ions by enhancing the conductivity and decreasing the diffusion energy barrier but also generates more reactivity sites, as demonstrated by density functional theory calculations. By virtue of these superiorities, the SnSe0.5S0.5 @ NG exhibits superior sodium storage performance with high‐rate capability and long durability over 2000 cycles at 2 A g−1. Impressively, the full battery, when coupling SnSe0.5S0.5 @ NG anode with Na3V2(PO4)3/C cathode, can deliver high energy density of 213 Wh kg−1. This work provides an effective structural engineering strategy to design advanced electrode material with potential application for sodium‐ion batteries. [ABSTRACT FROM AUTHOR]

Sodium-based dual-ion batteries have received increased attention owing to their appealing cell voltage (i.e., >3 V) and cost-effective features. However, the development of high-performance anode materials is one of the key elements for exploiting this electrochemical energy storage system at practical levels. Here, we report a source-template synthetic strategy for fabricating a variety of nanowire-in-nanotube MSxTey@C (M = Mo, W, Re) structures with an in situ-grown carbon film coating, termed as nanocables. Among the various materials prepared, the MoS1.5Te0.5@C nanocables are investigated as negative electrode active material in combination with expanded graphite at the positive electrode and NaPF6-based non-aqueous electrolyte solutions for dual-ion storage in coin cell configuration. As a result, the dual-ion lab-scale cells demonstrate a prolonged cycling lifespan with 97% capacity retention over 1500 cycles and a reversible capacity of about 101 mAh g−1 at specific capacities (based on the mass of the anode) of 1.0 A g−1 and 5.0 A g−1, respectively. Sodium-based dual-ion batteries are promising electrochemical energy storage devices. Here, the authors report a source-template synthetic strategy to prepare carbon-coated MoS1.5Te0.5 nanocables and their use as anode active materials in Na-based dual ion cells. [ABSTRACT FROM AUTHOR]

Sodium‐tellurium (Na‐Te) battery, thanks to high theoretical capacity and abundant sodium source, has been envisaged as one promising battery technology, its practical application yet faces daunting challenges regarding how to mitigate the critical issues of uncontrollable dendrites growth at Na anode and polytellurides shuttling effect at Te cathode. We here report an elaborative design for fabrication of microsphere skeleton nanohybrids with three‐dimensional (3D) hierarchical porous carbon loading CeO2 quantum dots (CeO2‐QDs/HPC), which feature highly favorable properties of sodiophilic and catalysis for hosting sodium and tellurium, respectively. The systematic investigations coupling with first‐principle calculations demonstrate the CeO2‐QDs/HPC not only offers favorable structure and abundant electrocatalytic sites for facilitating interconversion between Te and NaxTe as a cathode host, but also can function as dendrite inhibitor anode host for reversible sodium electro‐plating/deposition. Such Na‐Te battery exhibits admiring electrochemical performance with an impressive specific capacity of 392 mAh g−1, a long cycling stability over 1000 cycles, as well as remarkably high energy density of 192 Wh kg−1 based on the total mass of anode and cathode. Such proof‐of‐concept bifunctional host design for active electrode materials can render a new insight and direction to the development of high‐performance Na‐Te batteries. [ABSTRACT FROM AUTHOR]

Electrolysis systems constructed by anodic urea oxidation reaction (UOR) and cathodic hydrogen evolution reaction (HER) have received considerable attention in sustainable energy and waste utilization. However, current electrolysis systems are far from the requirement of practical applications due to the limited catalytic activity and stability of the electrodes. Herein, we design a UOR electrode with Co-doped NiMoO4 treated in Ar (NCMO–Ar), which shows superior UOR performance because of the Co doping. On the other hand, the Co-doped NiMoO4 treated in H2 (NCMO–H2) delivers high activity for HER. Moreover, the use of a flow electrolysis cell is demonstrated with continuous injection of urea, which only requires a low operation potential of 1.342 V to reach 10 mA cm−2, and shows no attenuation at a large operation current of 100 mA cm−2 for 200 h. It is believed that this high-performance electrolysis system lays an important foundation in developing a practical electrolyzer for efficient and sustainable hydrogen production coupled with waste organic oxidation. [ABSTRACT FROM AUTHOR]

Sodium‐ion hybrid capacitors (SIHCs) have been regarded as one of the promising energy devices thanks to its low cost and compromise between energy density and power density, yet remain a challenge towards practical levels of mass loading (>10 mg cm−2). Herein, the fabrication of a 1D core–shell structure is reported with N‐doped porous carbon encapsulating ZnV2O4 nanofibers (ZnV2O4NFs@N‐PC), which features an open framework and favorable properties for facilitating ion diffusion, mass transportation, and electron transfer, enabling it to perform impressively for sodium ions storage. A 3D printed SIHC is conceptually proposed by coupling the 3D printed ZnV2O4NFs@N‐PC anode with a 3D printed active carbon cathode, which can deliver a high energy/power density of 145.07 Wh kg−1/3677.1 W kg−1 with a durable cycling lifespan. It is demonstrated that the 3D printed SIHC, even at a high mass loading of up to 16.25 mg cm−2, can release a high areal energy/power density of 1.67 mWh cm−2/38.96 mW cm−2, outperforming most of the SIHCs developed so far. The present work sheds light on the role of the design of electrode materials and verifies the promise of 3D‐printed technology for next‐generation electrochemical energy devices. [ABSTRACT FROM AUTHOR]

The fabrication of crystalline COF materials with predictable structures and desirable features is one of the crystal engineering strategic goals. Many synthetic factors play an invisible role in the crystallization of COFs, and the nature of the solvent is one of the most influential. Herein, we synthesized two series of benzothiadiazole-based COFs using three pairs of solvent systems of different polarities to explore the effect on the COF synthesis product crystallization, as well as the photocatalytic performance of H2 evolution under visible light irradiation. The results showed that the crystallinity of the COFs increases with increasing solvent polarity. This work showed that increasing the solvent polarity not only enhanced the crystallinity, but also enhanced the thermal stability and gave highly crystalline COFs with a shorter reaction time (30 min). More interestingly, the amorphous materials generated by the use of less solvent polarity (dioxane) can be transferred into crystalline COFs by increasing the polarity of the solvent with butanol or ethanol. The high crystallinity COFs exhibited excellent hydrogen evolution rates. Therefore, this work demonstrates that the choice of solvent is very important. [ABSTRACT FROM AUTHOR]

The development of highly efficient cathodes for hydrogen production that can operate in a suitable pH condition is a daunting challenge in microbial electrolysis cells (MECs). Herein, an asymmetric neutral‐alkaline double‐chamber microbial electrolysis cells (AMECs) by using conventional carbon brush with microorganism attached as neutral anode and the Ru/CNTs electrode as alkaline cathode, respectively, was proposed. To implement this, a hybrid with ruthenium nanoparticles loaded on conductive carbon nanotubes (Ru/CNTs) was prepared by a reduction deposition method, which exhibited comparable electrocatalytic performance to the expensive benchmark Pt/C catalysts for hydrogen evolution reaction (HER). Compared to the traditional MECs running in symmetric neutral electrolyte, the as‐developed AMEC displayed a higher current density of 17.13 A m−2 and hydrogen production rate of 0.167 m3 m−2 d−1. The present AMEC provides an energy‐saving and cost‐effective process technology for electrolysis H2 generation. [ABSTRACT FROM AUTHOR]

Zinc (Zn) ion hybrid capacitors (ZIHCs) are promising energy storage devices with the integrated merits of high-capacity Zn-ion batteries and high-power supercapacitors. Their practical application yet remains a challenge due to the relatively low energy density and poor longevity. Herein, a hierarchical porous carbon sphere (HPCS) co-doped with N, P and S is developed, which is featured with a three-dimensional (3D) porous frame structure to deliver a short mass transfer pathway, fast kinetics and enhanced conductivity. The ZIHCs with HPCS-900 as the cathode material enables a large capacity of 104.7 mA h g−1 and excellent energy/power density of 90.17 W h kg−1/81.2 W kg−1 within the voltage window of 0.1–1.7 V. The HPCS-900-based ZIHCs affords a high stability up to 30 000 cycles with a high capacity retention of 95.24%. The HPCS-900 coupled soft-pack ZIHC device exhibits high capacity, high-rate capability and high stability, indicating the great potential of ZIHCs in practical applications. [ABSTRACT FROM AUTHOR]

WS2 nanosheets hold great promise for a variety of applications yet faces a grand challenge in terms of large‐scale synthesis. We report a reliable, scalable, and high‐yield (>93 %) synthetic strategy to fabricate WS2 nanosheets, which exhibit highly desirable electrocatalytic properties toward both the alkaline sulfion (S2−) oxidation reaction (SOR) and the acidic hydrogen evolution reaction (HER). The findings prompted us to develop a hybrid alkali‐acid electrochemical cell with the WS2 nanosheets as bifunctional electrode catalysts of alkaline anodic SOR and acidic cathodic HER. The proof‐of‐concept device holds promise for self‐power or low‐electricity electrolytic H2 generation and environmentally friendly recycling of sulfion with enhanced electron utilization efficiency. [ABSTRACT FROM AUTHOR]

Hydrogen (H2) has been utilized as a versatile feedstock or promising energy carrier in a variety of fields, yet the implementation of high‐rate H2 production presents a grand challenge for its readily accessible application. Herein, a newly alkali‐Al/acid hybrid fuel cell (3AHFC) that shows the capability of rapidly producing H2 upon delivering a considerably high energy density is reported, which is set up by paring Al anode in alkaline anolyte with acidic catholyte and a relatively cheap nanohybrid of Ru nanoparticle decorating crumpled reduced graphene oxide (Ru/c‐rGO) as cathode catalysts. It is demonstrated that the 3AHFC can release a power density of up to 240.6 mW cm−2 with a Faradic efficiency of approaching 99% for fast H2 generation (300 mA cm−2). Such hybrid electrolyte H2‐generation fuel cell can also be extended for either seawater anolyte or metallic Mg anode, presenting great promise for the practice feasibility of on‐site H2 production for applications in tough or even extreme environments. [ABSTRACT FROM AUTHOR]

Sodium‐based dual‐ion batteries (SDIBs) have been envisaged as one of the promising rechargeable energy storage devices by virtue of the low cost and considerably high energy density. But the exploration of high‐performance anode materials yet remain a grand challenge. Herein, an elaborate design is reported to fabricate nanohybrids of N‐doped carbon film modifying MoSSe nanosheets supported on hollow cubic N‐doped carbon (MoSSeNSs@NC/hC‐NC), which features abundant anionic defects, few‐layered MoSSe with expanded interlayer spacing, good conductivity, and hollow structure. These favorable properties and structure are greatly conducive for Na+ storage, as evidenced by displaying desirable electrochemical properties of high capacity, good rate capability, and excellent stability. The impressive capability for Na+ storage in the MoSSeNSs@NC/hC‐NC motivates to set up a full SDIBs device by coupling with EG cathode, which show a discharge capacity of 185 mA h g–1 at 1 A g–1 with the capacity retention of almost 100% over 2000 cycles. [ABSTRACT FROM AUTHOR]

Electrochemical reduction of CO2 (CO2RR) into valuable hydrocarbons is appealing in alleviating the excessive CO2 level. We present the very first utilization of metallic bismuth–tin (Bi‐Sn) aerogel for CO2RR with selective HCOOH production. A non‐precious bimetallic aerogel of Bi‐Sn is readily prepared at ambient temperature, which exhibits 3D morphology with interconnected channels, abundant interfaces and a hydrophilic surface. Superior to Bi and Sn, the Bi‐Sn aerogel exposes more active sites and it has favorable mass transfer properties, which endow it with a high FEHCOOH of 93.9 %. Moreover, the Bi‐Sn aerogel achieves a FEHCOOH of ca. 90 % that was maintained for 10 h in a flow battery. In situ ATR‐FTIR measurements confirmed that the formation of *HCOO is the rate‐determining step toward formic acid generation. DFT demonstrated the coexistence of Bi and Sn optimized the energy barrier for the production of HCOOH, thereby improving the catalytic activity. [ABSTRACT FROM AUTHOR]

The continuously increasing CO2 released from human activities poses a great threat to human survival by fluctuating global climate and disturbing carbon balance among the four reservoirs of the biosphere, earth, air, and water. Converting CO2 to value-added feedstocks via electrocatalysis of the CO2 reduction reaction (CO2RR) has been regarded as one of the most attractive routes to re-balance the carbon cycle, thanks to its multiple advantages of mild operating conditions, easy handling, tunable products and the potential of synergy with the rapidly increasing renewable energy (i.e., solar, wind). Instead of focusing on a special topic of electrocatalysts for the CO2RR that have been extensively reviewed elsewhere, we herein present a rather comprehensive review of the recent research progress, in the view of associated value-added products upon selective electrocatalytic CO2 conversion. We initially provide an overview of the history and the fundamental science regarding the electrocatalytic CO2RR, with a special introduction to the design, preparation, and performance evaluation of electrocatalysts, the factors influencing the CO2RR, and the associated theoretical calculations. Emphasis will then be given to the emerging trends of selective electrocatalytic conversion of CO2 into a variety of value-added products. The structure-performance relationship and mechanism will also be discussed and investigated. The outlooks for CO2 electrocatalysis, including the challenges and opportunities in the development of new electrocatalysts, electrolyzers, the recently rising operando fundamental studies, and the feasibility of industrial applications are finally summarized. [ABSTRACT FROM AUTHOR]

Flexible and wearable sensors have shown great potential in tremendous applications such as human health monitoring, smart robots, and human–machine interfaces, yet the lack of suitable flexible power supply devices remains a great challenge hindering their practical applications. To this end, it is essential to develop novel flexible power supply devices that are highly flexible, lightweight, miniaturized, stable, and adaptable for the integration of a self-powered wearable system. Synthesizing intrinsically flexible materials and providing rigid materials good flexibility by a rational architectural design represent the most straightforward approaches to prepare flexible electrode and electrolyte materials, which lay the foundation for the assembly of flexible power devices. Besides, device configuration design and system integration are also essential steps to pave the way for flexible power devices towards real wearable applications. Herein, the main fabrication strategies including material synthesis, architecture design, device configuration design, and system integration for fabricating flexible power devices are overviewed. In addition, the existing challenges and future directions for the development of flexible power supply devices towards self-powered wearable systems will be discussed. [ABSTRACT FROM AUTHOR]

Electrocatalytic nitrogen reduction reaction (NRR) plays a vital role for next‐generation electrochemical energy conversion technologies. However, the NRR kinetics is still limited by the sluggish hydrogenation process on noble‐metal‐free electrocatalyst. Herein, we report the rational design and synthesis of a hybrid catalyst with atomic iron sites anchored on a N,O‐doped porous carbon (FeSA‐NO‐C) matrix of an inverse opal structure, leading to a remarkably high NH3 yield rate of 31.9 μgNH3 h−1 mg−1cat. and Faradaic efficiency of 11.8 % at −0.4 V for NRR electrocatalysis, outperformed almost all previously reported atomically dispersed metal‐nitrogen‐carbon catalysts. Theoretical calculations revealed that the observed high NRR catalytic activity for the FeSA‐NO‐C catalyst stemmed mainly from the optimized charge‐transfer between the adjacent O and Fe atoms homogenously distributed on the porous carbon support, which could not only significantly facilitate the transportation of N2 and ions but also effectively decrease the binding energy between the isolated Fe atom and *N2 intermediate and the thermodynamic Gibbs free energy of the rate‐determining step (*N2 → *NNH). [ABSTRACT FROM AUTHOR]

Multi‐dimensional hierarchical nanostructures can efficiently promote the mass transportation and electron transfer of electrocatalysts, which can boost the electrocatalytic performance. In this study, we report the design of a hierarchical carbon/metal nanostructure (Co@CNFs) with the combination of 0D cobalt metal nanoparticles, 1D carbon nanofibers, and 2D carbon nanosheets as a bifunctional oxygen reduction/evolution reaction (ORR/OER) catalyst. The Co@CNF catalysts are prepared by using a facile approach of combining electrospinning, impregnation growth of ZIF‐67 nanosheets, and high‐temperature carbonization. Through rationally optimizing the synthesis conditions, including the chemical concentration and carbonization temperature, the optimal catalyst of Co@CNFs‐50‐800 features a hierarchical structure of continuous carbon nanofibers (CNFs)‐anchored carbon nanosheets wrapping Co nanoparticles, which holds decent catalytic activities in term of a half‐wave potential of 0.8 V for the ORR and a potential of 1.54 V for the OER at 10 mA cm−2. A rechargeable Zn‐air battery is set up using the catalyst as the air cathode, which exhibits a high specific capacity of 809 mAh g−1 and a peak power density of 165.5 mW cm−2, as well as a good durability up to 1000 charging‐discharging cycles (>160 h), which is even better than the benchmark Pt/C+RuO2 catalyst. This study provides a rational strategy to design hierarchically nanostructural catalysts to boost the mass transportation and electron transfer of electrocatalytic reactions. [ABSTRACT FROM AUTHOR]

The rise of portable and wearable electronics has largely stimulated the development of flexible energy storage and conversion devices. As one of the essential parts, the electrode plays critical role in determining the device performance, which required to be highly flexible, light‐weight, and conformable for flexible and wearable applications. However, it remains a formidable challenge in the design of appropriate flexible electrodes. Thus, considerable effort has been making to develop various flexible materials/substrates to fabricate flexible energy devices. Here, this review aims to provide a comprehensive survey on the recently developed free‐standing and flexible electrode materials/substrates for flexible electrochemical energy storage devices, which are categorized into four different types including metal‐based, carbon‐based, polymer‐based, and micro‐patterned flexible electrodes. The specific characteristics, fabrication methods, properties, and pros and cons of each type of materials are thoroughly analysed. Furthermore, challenges and future directions for designing flexible electrode materials are also discussed. [ABSTRACT FROM AUTHOR]

Aqueous electrochemical devices such as batteries and electrolytic cells have emerged as promising energy storage and conversion systems owing to their environmental friendliness, low cost, and high safety characteristics. However, grand challenges are faced to address some critical issues, including how to enhance the potential window and energy density of electrochemical power devices (e.g. fuel cells, batteries, and supercapacitors), and how to minimize the energy consumption in electrolysis. The use of decoupled acid–base asymmetric electrolytes shows great potential in improving the performance of aqueous devices by electrochemically converting the conventional thermal energy of acid–base neutralization into electricity, i.e., electrochemical neutralization energy (ENE). This review aims to introduce the little-known concept of the ENE, including its development history, thermodynamic fundamentals, operating principles, device configurations, and applications. The recent progress made in ENE-assisted electrochemical energy devices emphasizing fuel cells, batteries, supercapacitors, and electrolytic cells is summarized specifically. Finally, the challenges and future perspectives of ENE associated technology are discussed. It is believed that this tutorial review will give a better understanding of the mechanism and operating principles of the ENE to newcomers, which would shed light on the innovative design and fabrication of ENE-assisted devices and thus pave the way for the development of high-performance aqueous electrochemical energy devices. [ABSTRACT FROM AUTHOR]