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In both the manufacturing and chemical industries, benzoquinone is a crucial chemical product. A perfect and economical method for making benzoquinone is the electrochemical oxidation of phenol, thanks to the traditional thermal catalytic oxidation of phenol process requires high cost, serious pollution and harsh reaction conditions. Here, a unique heterostructure electrocatalyst on nickel foam (NF) consisting of nickel sulfide and nickel oxide (Ni9S8‐Ni15O16/NF) was produced, and this catalyst exhibited a low overpotential (1.35 V vs. RHE) and prominent selectivity (99 %) for electrochemical phenol oxidation reaction (EOP). Ni9S8‐Ni15O16/NF is beneficial for lowering the reaction energy barrier and boosting reactivity in the EOP process according to density functional theory (DFT) calculations. Additionally, an alkali/acid hybrid flow cell was successfully established by connecting Ni9S8‐Ni15O16/NF and commercial RuIr/Ti in series to catalyze phenol oxidation in an alkaline medium and hydrogen evolution in an acid medium, respectively. A cell voltage of only 0.60 V was applied to produce a current density of 10 mA cm−2. Meanwhile, the system continued to operate at 0.90 V for 12 days, showing remarkable long‐term stability. The unique configuration of the acid‐base hybrid flow cell electrolyzer provides valuable guidance for the efficient and environmentally friendly electrooxidation of phenol to benzoquinone. [ABSTRACT FROM AUTHOR]

The electrochemical desalination technique is recognized as a promising solution to alleviate freshwater shortages, challenges yet persists in achieving optimal energy efficiency and cost‐effectiveness. Herein, a hybrid acid/alkali zinc air desalination battery (hAA‐ZADB) capable of concurrent desalination and high‐power density is reported. To improve cathodic efficiency and cost‐effectiveness, an electrocatalyst with dual atomic Fe–Mn sites on porous dodecahedral carbon (Mn‐Fe/p‐DC) is fabricated through a simple direct pyrolysis strategy for oxygen reduction reaction (ORR). The Mn–Fe/p‐DC‐900 electrocatalyst demonstrates exceptional electrocatalytic activity (E1/2 = 0.8 V in 0.5 m H2SO4) for ORR. This innovative hybrid acid/alkali cell design, coupled with advanced electrocatalysts, empowers the hAA‐ZADB system to achieve outstanding performance benchmarks with a high open circuit voltage of 2.22 V, an impressive power density of 375 mW cm−2, and notably elevated energy output of 106.9 kJ mol−1 even at a current density of 100 mA cm−2 during desalination. Distinguishing this work is its additional functionality, evident in a rapid salt removal rate of 3.64 mg cm−2 min−1 during desalination, achieving an impressive 88.67% removal of 0.6 M NaCl. This study highlights the promising potential of employing metallic air batteries for a self‐powered desalination technique applicable to specific scenarios. [ABSTRACT FROM AUTHOR]

Rechargeable Zn–air batteries (ZABs) are considered highly competitive technologies for meeting the energy demands of the next generation, whether for energy storage or portable power. However, their practical application is hindered by critical challenges such as low voltage, CO2 poisoning at the cathode, low power density, and poor charging efficiency Herein, a rechargeable hybrid alkali/acid Zn–air battery (h‐RZAB) that effectively separates the discharge process in an acidic environment from the charging process in an alkaline environment, utilizing oxygen reduction reaction (ORR) and glycerol oxidation reaction (GOR) respectively is reported. Compared to previously reported ZABs, this proof‐of‐concept device demonstrates impressive performance, exhibiting a high power density of 562.7 mW cm−2 and a high operating voltage during discharging. Moreover, the battery requires a significantly reduced charging voltage due to the concurrent utilization of biomass‐derived glycerol, resulting in practical and cost‐effective advantages. The decoupled system offers great flexibility for intermittently generated renewable power sources and presents cost advantages over traditional ZABs. As a result, this technology holds significant promise in opening avenues for the future development of renewable energy‐compatible electrochemical devices. [ABSTRACT FROM AUTHOR]

Aqueous zinc (Zn) based batteries show great promise as energy storage devices, cost‐effectiveness, and intrinsic safety. However, the development of Zn‐based batteries faces significant challenges, primarily stemming from poor electrochemical reversibility caused by dendrite growth, hydrogen generation, and byproduct formation on the Zn anode. In this study, valine (Val) is investigated as an electrolyte additive to finely tune the interface microenvironment, resulting in enhanced electrochemical stability of the Zn anode across a wide pH range, marking the first time such an approach has been explored. Val ions preferably adsorb onto the active sites of the Zn anode surface, enabling efficient isolation of water and SO42− from the desolvated shell layer and thus effectively inhibiting dendrite growth. The Zn||Zn symmetric cells are demonstrated with Val electrolyte additives present a remarkable cycling performance of 5400 h. Furthermore, Zn||MnO2 full cells exhibit stable operation for 5000 cycles at 3 A g−1. Notably, the Val additive also functions effectively in rechargeable alkaline cells, enabling the alkaline symmetric cells and Zn||Ni0.8Co0.1Mn0.1O2 full cells to operate durably across a wide temperature range. This work offers unique insights into electrolyte engineering for aqueous rechargeable batteries, especially in terms of their compatibility with a wide pH range. [ABSTRACT FROM AUTHOR]

Alloying‐type antimony (Sb) with high theoretical capacity is a promising anode candidate for both lithium‐ion batteries (LIBs) and sodium‐ion batteries (SIBs). Given the larger radius of Na+ (1.02 Å) than Li+ (0.76 Å), it was generally believed that the Sb anode would experience even worse capacity degradation in SIBs due to more substantial volumetric variations during cycling when compared to LIBs. However, the Sb anode in SIBs unexpectedly exhibited both better electrochemical and structural stability than in LIBs, and the mechanistic reasons that underlie this performance discrepancy remain undiscovered. Here, using substantial in situ transmission electron microscopy, X‐ray diffraction, and Raman techniques complemented by theoretical simulations, we explicitly reveal that compared to the lithiation/delithiation process, sodiation/desodiation process of Sb anode displays a previously unexplored two‐stage alloying/dealloying mechanism with polycrystalline and amorphous phases as the intermediates featuring improved resilience to mechanical damage, contributing to superior cycling stability in SIBs. Additionally, the better mechanical properties and weaker atomic interaction of Na−Sb alloys than Li−Sb alloys favor enabling mitigated mechanical stress, accounting for enhanced structural stability as unveiled by theoretical simulations. Our finding delineates the mechanistic origins of enhanced cycling stability of Sb anode in SIBs with potential implications for other large‐volume‐change electrode materials. [ABSTRACT FROM AUTHOR]

Sodium borohydride (NaBH4) has earned recognition as a promising hydrogen carrier, attributed to its exceptional hydrogen storage capacity, boasting a high theoretical storage capacity of 10.8 wt %. Nonetheless, the utilization of traditional pyrolysis and hydrolysis methods still presents a formidable challenge in achieving controlled hydrogen generation especially under ambient conditions. In this work, we report an innovative electrochemical strategy for production H2 by coupling NaBH4 electrooxidation reaction (BOR) at anode in alkaline media with hydrogen evolution reaction (HER) at cathode in acidic media. To implement this, we have developed a bifunctional electrocatalyst denoted as Pd‐Mo2C@CNTs, wherein Pd nanoparticles are grown in situ on Mo2C embedded within N‐doped carbon nanotubes. This electrocatalyst demonstrates exceptional performance in catalyzing both alkaline BOR and acidic HER. We have developed a hybrid acid/alkali cell, utilizing Pd/Mo2C@CNTs as the anode and cathode electrocatalysts. This configuration showcases remarkable capabilities for self‐sustained, precise, and uninterrupted indirect release of H2 stored in NaBH4, even at high current densities of 100 mA cm−2 with a Faraday efficiency approaching 100 %. Additionally, this electrochemical device exhibits significant promise as a fuel cell, with the ability to deliver a maximum power density of 20 mW cm−2. [ABSTRACT FROM AUTHOR]

Transition metal single atoms anchored on nitrogen‐doped carbon (M‐N‐C) matrix with M‐N‐C active sites have shown to be promising catalysts for both hydrogen evolution reaction (HER) and oxygen reduction reaction (ORR). Herein, a hybrid catalyst with low‐level loading of atomic Pt and Co species encapsulated in nitrogen‐doped graphene (Pt@CoN4‐G) is developed. The Pt@CoN4‐G shows low overpotential for HER in wide‐pH electrolyte and manifests improved mass activity with almost eight times greater than that of Pt/C at an overpotential of 50 mV. The Pt@CoN4‐G also exhibits a top‐level ORR activity (half‐wave potential, E1/2 = 0.893 V) and robust stability (>200 h) in alkaline medium. Using theoretical calculations and comprehensive characterizations , the strong metal–support interactions between Pt species and CoN4‐G support and synergistical cooperation of multiple active sites are clarified. A flow alkali‐Al/acid hybrid fuel cell using Pt@CoN4‐G as cathode catalyst delivers a large power density of 222 mW cm−2 with excellent stability to achieve simultaneously hydrogen evolution and electricity generation. In addition, Pt@CoN4‐G endows a flow Zn‐air battery with high power density (316 mW cm−2), good stability under large current density (>100 h at 100 mA cm−2), and long cycle life (over 600 h at 5 mA cm−2). [ABSTRACT FROM AUTHOR]

The development of high‐performance sodium ion batteries (SIBs) is heavily relied on the exploration of the appropriate electrode material for Na+ storage, which ought to feature merits of high capacity, easy‐to‐handle synthesis, high conductivity, expedite mass transportation, and stable structure upon charging–discharging cycle. Herein, a universal source‐template method is reported to synthesize a variety of transition metal (e.g., V, Sb, W, Zn, Fe, Co, Ni, and Cu) selenides implanting on N doped 3D carbon nanoarchitecture hybrids (MmSen@3D‐CN) with powerful SeC bonding rivet. Benefiting from the superior architecture and potent SeC bonding between Cu2−xSe and N‐doped 3D carbon (3D‐CN), the Cu2−xSe@3D‐CN nanohybrids, as anode of SIBs, show high capacity, high‐rate capability, and long‐cycle durability, which can deliver a reversible capacity of as high as 386 mAh g−1, retain 219 mAh g−1 even at 10 A g−1, and run durably over thousands of charging–discharging cycles. The Cu2−xSe@3D‐CN as anode is also evaluated by developing a full SIB by coupling with the Na3V2(PO4)3 cathode, which can deliver high energy density and show excellent stability, shedding light on its potential in practical application. [ABSTRACT FROM AUTHOR]

Electrosynthesis of H2O2 has great potential for directly converting O2 into disinfectant, yet it is still a big challenge to develop effective electrocatalysts for medical‐level H2O2 production. Herein, we report the design and fabrication of electrocatalysts with biomimetic active centers, consisting of single atomic iron asymmetrically coordinated with both nitrogen and sulfur, dispersed on hierarchically porous carbon (FeSA‐NS/C). The newly‐developed FeSA‐NS/C catalyst exhibited a high catalytic activity and selectivity for oxygen reduction to produce H2O2 at a high current of 100 mA cm−2 with a record high H2O2 selectivity of 90 %. An accumulated H2O2 concentration of 5.8 wt.% is obtained for the electrocatalysis process, which is sufficient for medical disinfection. Combined theoretical calculations and experimental characterizations verified the rationally‐designed catalytic active center with the atomic Fe site stabilized by three‐coordinated nitrogen atoms and one‐sulfur atom (Fe‐N3S‐C). It was further found that the replacement of one N atom with S atom in the classical Fe‐N4‐C active center could induce an asymmetric charge distribution over N atoms surrounding the Fe reactive center to accelerate proton spillover for a rapid formation of the OOH* intermediate, thus speeding up the whole reaction kinetics of oxygen reduction for H2O2 electrosynthesis. [ABSTRACT FROM AUTHOR]

Aqueous zinc‐based batteries with high energy density are highly sought after to satisfy the increasing demands on the electrochemical energy device thanks to the advantages of high safety, low cost, and fast kinetics. In this work, a high‐performance hybrid Zn–S battery (h‐ZnSB) is reported by coupling an alkali Zn anode with an acidic sulfur electrode. To this end, atomic Zn–N4 dispersed on nitrogen‐doped hollow porous carbon (Zn–NHPC) is developed as the host of sulfur that enhances efficiency due to the higher affinity of Zn–N4 to CuS than N‐doped graphene, which can reduce the vulcanization reaction barrier that is too high on N‐doped graphene. The hybrid Zn–S battery shows desired electrochemical properties, including a high open‐circuit voltage of 1.81 V, high specific capacities of 2250 mAh g−1 at 1 A g−1 and 1500 mAh g−1 at 10 A g−1, as well as a high energy density of 2372 Wh kg−1 at 10 A g−1 based on the total mass of S/C composites. The present work may provide a promising route for the development of high‐energy and high‐safety aqueous batteries. [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]

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‐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]

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 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]

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]

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]

Glycerol, as the major by‐product of biodiesel, can be oxidized into diverse value‐added chemical products via either traditional chemical methods or electrochemical routes. Electrocatalytic glycerol oxidation reaction (GOR) driven by renewable‐derived electricity (e.g., wind and solar) is a promising pathway for fine chemicals production. In an electrochemical cell, GOR can be coupled with various cathodic reactions, including hydrogen evolution reaction (HER), CO2 reduction reaction (CO2RR), and oxygen reduction reaction (ORR); in this manner, different benefits of either energy effectiveness or additional value‐added products can be obtained depending on the cathode reduction reaction selected. Comprehensively understanding of electrocatalytic GOR and the associated processes is of great significance to promote its industrial application. Herein, recent progress of GOR is focused on. The background of biomass‐derived glycerol valorization to energy and value‐added chemicals as well as the electrochemical conversion techniques via GOR is introduced. Then, the electrocatalytic reaction pathways, the potential application of GOR, and the measurement method for products are also discussed and summarized. Special emphasis is put on the design and the development of high‐selectivity and high‐activity electrocatalysts for GOR. Finally, the challenges and the future prospects in the fields of GOR are highlighted. [ABSTRACT FROM AUTHOR]

Aqueous rechargeable batteries have attracted attention owning to their advantages of safety, low cost, and sustainability, while the limited electrochemical stability window (1.23 V) of water leads to their failure in competition with organic‐based lithium‐ion batteries. Herein, we report an alkali–acid Zn–PbO2 hybrid aqueous battery obtained by coupling an alkaline Zn anode with an acidic PbO2 cathode. It shows the capability to deliver an impressively high open‐circuit voltage (Voc) of 3.09 V and an operate voltage of 2.95 V at 5 mA cm−2, thanks to the contribution of expanding the voltage window and the electrochemical neutralization energy from the alkali–acid asymmetric‐electrolyte hybrid cell. The hybrid battery can potentially deliver a large area capacity over 2 mAh cm−2 or a high energy density of 252.39 Wh kg−1 and shows almost no fading in area capacity over 250 charge–discharge cycles. [ABSTRACT FROM AUTHOR]

Two‐dimensional (2D) monometallic pnictogens (antimony or Sb, and bismuth or Bi) nanosheets demonstrate potential in a variety of fields, including quantum devices, catalysis, biomedicine and energy, because of their unique physical, chemical, electronic and optical properties. However, the development of general and high‐efficiency preparative routes toward high‐quality pnictogen nanosheets is challenging. A general method involving a molten‐salt‐assisted aluminothermic reduction process is reported for the synthesis of Sb and Bi nanosheets in high yields (>90 %). Electrocatalytic CO2 reduction was investigated on the Bi nanosheets, and high catalytic selectively to formate was demonstrated with a considerable current density at a low overpotential and an impressive stability. Bi nanosheets continuously convert CO2 into formate in a flow cell operating for one month, with a yield rate of 787.5 mmol cm−2 h−1. Theoretical results suggest that the edge sites of Bi are far more active than the terrace sites. [ABSTRACT FROM AUTHOR]

Development of low cost electrocatalysts with outstanding catalytic activity and stability for oxygen evolution reaction (OER) in acid is a major challenge to produce hydrogen energy from water splitting. Herein, a novel metal‐free electrocatalyst consisting of a oxygen‐functionalized electrochemically exfoliated graphene (OEEG) nanosheets array is reported. Benefitting from a vertically aligned arrays structure and introducing oxygen functional groups, the metal‐free OEEG nanosheets array exhibits superior electrocatalytic activity and stability toward OER with a low overpotential of 334 mV at 10 mA cm−2 in acidic electrolyte. Such a high OER performance is thus far the best among all previously reported metal‐free carbon‐based materials, and even superior to commercial Ir/C catalysts (420 mV at 10 mA cm−2) in acid. Characterization results and electrochemical measurements identify the COOH species in the OEEG acting as active sites for acidic OER, which is further supported by atomic‐scale scanning transmission electron microscopy imaging and electron energy‐loss spectroscopy. Density functional theory calculations reveal that the reaction pathway of dual sites that is mixed by zigzag and armchair edges (COOH‐zig‐corner) is better than the pathway of single site. [ABSTRACT FROM AUTHOR]

Charge carriers separation and surface catalytic reactions are two crucial steps in photocatalytic processes; the rational design of photocatalysts by taking these two factors into consideration is thus of great importance to advance the associated performance. Herein, a self‐sacrificial strategy is developed to fabricate a ternary nanostructure photocatalyst, forming a hierarchical architecture of In(OH)3 nanocube decorated NiS‐ZnIn2S4 (ZIS) hybrid nanosheets (ZIS/In(OH)3‐NiS). Such a unique structure provides the hybrid photocatalyst with a facilitated path for efficiently separating the charge carrier and abundant sites for catalytic reactions. Systematic characterizations that reveal the strong electronic interactions in the ternary ZIS/In(OH)3‐NiS leads to fast electron transfer from excited ZnIn2S4 to NiS nanosheets, which provide catalytic sites for hydrogen evolution reaction. The comprehensive photocatalysis studies demonstrate that ZnIn2S4/In(OH)3‐NiS exhibits ultrahigh photocatalytic activity toward hydrogen generation with a high rate of 7010 μmol g−1 h−1, which ranks as one of the highest among ZnIn2S4‐based photocatalysts reported so far. This work provides an attractive and effective way to develop high‐activity photocatalysts without using precious metal cocatalysts. The investigation brings us one step closer to understanding the structure‐determining properties of nanohybrid architecture, and provides a valuable reference to develop cost‐effective and practical photocatalysts for a variety of applications. [ABSTRACT FROM AUTHOR]

Conversing CO2 into value‐added chemicals endows electrochemical CO2 reduction reaction (CO2RR) with the potential to tackle over issues induced by the increased CO2 level in the atmosphere. The associated technological viability of this process is highly dependent on exploring efficient electrocatalysts. In this work, we successfully synthesized nitrogen and sulfur co‐doped carbon nanosheets (NS‐CNSs), which are comprehensively characterized by a variety of characterization techniques. When used as the catalyst for CO2RR, the NS‐CNSs exhibit remarkably high catalytic activity and selectivity with a Faradaic efficiency of ∼85.4 % for CO production and long‐term durability. The superior performance of this material majorly originates from the unique nanosheets structure with large porosity and the co‐doped S and N in the nanosheets, which exposed larger electrochemical activity surface areas and more active sites for promoting CO2 reduction. [ABSTRACT FROM AUTHOR]

It remains great challenge to develop precious‐metal‐free electrocatalysts to implement high‐activity electrochemical conversion of O2 into value‐added hydroperoxide species (HO2−), which are vulnerable when exposed to various transition‐metal‐based catalysts. A strategy based on steric hindrance and layered nickel‐based layered double hydroxide (Ni‐LDH) induction has been developed for one‐pot inlaying high‐density ultrathin 2 D Ni‐LDH chips on in situ‐grown carbon nanosheets (Ni‐LDH C/CNSs). The resulting material exhibits high electrocatalytic selectivity with a faradaic efficiency up to 95 % for oxygen reduction into peroxide and attains a fairly high mass activity of approximately 22.2 A g−1, outperforming most metal‐based catalysts reported previously. Systematic studies demonstrate that the greatly increased defect concentration at Ni edge sites of Ni‐LDH chips results in more active sites, which contributes a favorable thermodynamically neutral adsorption of OOH* and adsorbed H2O2 molecules relatively weakly. Additionally, the modified CNSs effectively suppress H2O2 decomposition and avoid O−O bond cleavage to produce H2O by steric effects. The synergistic effect of CNSs and Ni‐LDH chips therefore leads to high activity and high selectivity in a two‐electron pathway. A proof‐of‐concept zinc–air fuel cell is proposed and set up to demonstrate the feasibility of green synthesis of peroxide, generating an impressive H2O2 production rate of 5239.67 mmol h−1 gcat.−1. [ABSTRACT FROM AUTHOR]

We report a straightforward strategy to design efficient N doped porous carbon (NPC) electrocatalyst that has a high concentration of easily accessible active sites for the CO2 reduction reaction (CO2RR). The NPC with large amounts of active N (pyridinic and graphitic N) and highly porous structure is prepared by using an oxygen‐rich metal–organic framework (Zn‐MOF‐74) precursor. The amount of active N species can be tuned by optimizing the calcination temperature and time. Owing to the large pore sizes, the active sites are well exposed to electrolyte for CO2RR. The NPC exhibits superior CO2RR activity with a small onset potential of −0.35 V and a high faradaic efficiency (FE) of 98.4 % towards CO at −0.55 V vs. RHE, one of the highest values among NPC‐based CO2RR electrocatalysts. This work advances an effective and facile way towards highly active and cost‐effective alternatives to noble‐metal CO2RR electrocatalysts for practical applications. [ABSTRACT FROM AUTHOR]

Development of cost‐effective and highly efficient oxygen evolution reaction (OER) electrocatalysts has become a vital project of renewable energy technologies. The OER is critical for a variety of electrochemical energy devices such as water electrolyzers, metal‐air batteries, CO2 reduction, and electrosynthesis of ammonia. Compared to extensively studied metal oxide catalysts, graphitized carbon catalysts have been newly emerged as promising OER catalysts especially in less corrosive alkaline media, due to their low cost, high electrical conductivity, unique physicochemical properties, and excellent electrocatalytic performances. In this review, we discussed recent advances in nanostructured carbon electrocatalysts. At first, metal‐free OER carbon electrocatalysts including single‐ and multi‐heteroatom doping and edge‐ and defect‐rich defects are introduced. Then, transition metal and heteroatom co‐doped nanocarbons are summarized including Co−N−C, Ni−N−C, and Fe‐N−C. In addition, carbon based hybrid electrocatalysts are highlighted, which include carbon based transition metal nitrides (TMNx), sulfides (TMSx), and selenides (TMSex), and phosphides (TMPx). Finally, current challenges and perspective for future research on carbon‐based OER catalysts are outlined. [ABSTRACT FROM AUTHOR]

It is highly attractive to develop efficient water electrolysis route to implement hydrogen generation in a low‐cost way, which while requires excess energy to surmount the activation barriers majorly limited by oxygen evolution reaction at anode side. Herein, we report an acid‐alkali asymmetric‐electrolyte electrolyzer (AAAE) that can achieve substantial energy saving for electrolysis hydrogen generation, thanks to the assistance of electrochemical neutralization energy (ENE) and urea oxidation reaction (UOR). To this end, free‐standing Ni(OH)2 nanosheets on carbon cloth (Ni(OH)2−NSs/CC) is fabricated as catalytic anode for alkaline UOR, which manifests impressively high catalytic activity with delivering 10 mA cm−2 at 1.32 V and long‐term durability. The as‐developed AAAE only requires an applied voltage of 0.66 V to release the electrolysis current of 10 mA cm−2, yielding the H2 Faraday efficiency close to 100 % along with H2 production rate of 183.8 μmol h−1. [ABSTRACT FROM AUTHOR]

Developing efficient and low‐cost catalysts with excellent catalytic activities for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is of significance for large‐scale commercial applications in rechargeable Zn−air batteries and fuel cells. Herein, we develop a simple, mild and efficient method to synthesize a hybrid of N‐doped carbon nanosheets encapsulating cobalt nanoparticles (Co@NCNSs), which shows favorable catalytic properties toward both ORR and OER with high activity and good stability. The optimized hybrids (Co@NCNSs‐900) exhibit an onset potential of 0.95 V vs. reversible hydrogen electrode (RHE) and a half‐wave potential of 0.85 V vs. RHE for the ORR, and an onset potential of 1.51 V vs. RHE, a potential of 1.59 V vs. RHE at 10 mA cm−2 for the OER, as well as an oxygen electrode activity parameter (ΔE) of 0.802 V in alkaline electrolyte. Moreover, the Zn−air battery with the Co@NCNSs‐900 as the cathode catalyst outperforms that with the commercial Pt/C as cathode catalyst in terms of the maximum power density and stability, showing great prospects in renewable energy applications. [ABSTRACT FROM AUTHOR]

The oxygen reduction reaction (ORR), as one of the most critical but promising reactions for energy conversion, has attracted increasing research interest. Recent reports have evidenced that carbonization of heteroatoms doped porous organic polymers (POPs) is an effective approach toward highly efficient ORR electrocatalysts. We herein report a versatile ternary copolymerization strategy to synthesize stable POPs gel with tunable doping of heteroatoms (N, S, F) and Fe species, leading to significant enhancement in surface area and porosity. Carbonization of these POPs afford efficient ORR electrocatalyst with optimized composition, hierarchical porous structure and prominent catalytic activities in both alkaline and neutral conditions. The optimized catalyst (TF‐C‐900) exhibited an onset potential (Eonset) of 1.01 V and half‐wave potential (E1/2) of 0.88 V in 0.1 M KOH solution. These performance metrics are even comparable to those of the Pt/C (0.99 and 0.85). In addition, the TF‐C‐900 also showed superior stability and advantage of methanol tolerance, enabling them to be a competitive cathode electrocatalysts for alkaline fuel cell. Porous organic polymer gels synthesized via ternary polymerization were used to fabricate heteroatom‐doped catalysts for the oxygen reduction reaction and as cathode material in Zn‐air batteries. The porous structure showed prominent catalytic activity under both alkaline and neutral conditions, superior stability and advantage of methanol tolerance, enabling them to be a competitive cathode electrocatalysts for alkaline fuel cell. [ABSTRACT FROM AUTHOR]

Abstract: Developing cost‐effective electrocatalysts for high‐selectivity CO2 electroreduction remains challenging. We herein report a perfluorinated covalent triazine framework (CTF) electrocatalyst that displays very high selectivity in the electroreduction of CO2 to CH4 with a faradaic efficiency of 99.3 % in aqueous electrolyte. Systematic characterization and electrochemical studies, in combination with density functional theory calculations, demonstrate that the presence of both nitrogen and fluorine in the CTF provides a unique pathway that is inaccessible with the individual components for CO2 electroreduction. [ABSTRACT FROM AUTHOR]

Abstract: Sodium‐ion batteries (SIBs) have recently attracted increasing attention as the promising alternative to lithium‐ion batteries due to their multiple advantages of abundant reserves and low cost. However, the development of highly desirable anode materials suitable for SIBs is still hampered by a rather low capacity, poor rate capability, and cycling stability. Herein, a deliberate design to implement reliable and simple fabrication of an inverse opal structured nanohybrid of carbon‐confined various transition metal sulfides quantum dots (QDs) is presented. Comprehensive characterizations demonstrate that the hybrids hold a 3D architecture with uniform dispersion of QDs in a conductive carbon matrix that in turn encapsulates these quantum dots. With Co9S8 as an example, such a unique architecture, when applied as the anode of SIBs, endows the hybrids with multiple advantages including a high reversible specific capacity, extraordinary high rate capability, and excellent durability over 2000 cycles charging–discharging process. [ABSTRACT FROM AUTHOR]