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Sodium‐carbon dioxide (Na‐CO2) batteries are regarded as promising energy storage technologies because of their impressive theoretical energy density and CO2 reutilization, but their practical applications are restricted by uncontrollable sodium dendrite growth and poor electrochemical kinetics of CO2 cathode. Constructing suitable multifunctional electrodes for dendrite‐free anodes and kinetics‐enhanced CO2 cathodes is considered one of the most important ways to advance the practical application of Na‐CO2 batteries. Herein, RuO2 nanoparticles encapsulated in carbon paper (RuCP) are rationally designed and employed as both Na anode host and CO2 cathode in Na‐CO2 batteries. The outstanding sodiophilicity and high catalytic activity of RuCP electrodes can simultaneously contribute to homogenous Na+ distribution and dendrite‐free sodium structure at the anode, as well as strengthen discharge and charge kinetics at the cathode. The morphological evolution confirmed the uniform deposition of Na on RuCP anode with dense and flat interfaces, delivering enhanced Coulombic efficiency of 99.5% and cycling stability near 1500 cycles. Meanwhile, Na‐CO2 batteries with RuCP cathode demonstrated excellent cycling stability (>350 cycles). Significantly, implementation of a dendrite‐free RuCP@Na anode and catalytic‐site‐rich RuCP cathode allowed for the construction of a symmetric Na‐CO2 battery with long‐duration cyclability, offering inspiration for extensive practical uses of Na‐CO2 batteries. [ABSTRACT FROM AUTHOR]

Potassium‐ion hybrid capacitors (PIHCs) have attracted considerable attention as emerging electrochemical energy storage devices for simultaneously achieving high energy and power density, which the key to success is the development of compatible electrode materials for both battery‐type anode and capacitive cathode. Among numerous electrode materials, transition metal compounds (including oxides, chalcogenide, carbides, and nitrides) show great potential owing to their high theoretical capacity to achieve high energy density, but their sluggish reaction kinetics restrict the attainable power density. Hence, in the last few years, different strategies are proposed to improve the performance of transition metal compounds as electrode materials for PIHCs, and significant progress is achieved. Herein, this review outlines recent advances of employing transition metal compounds as electrode materials for PIHCs. The performance and challenges of different transition metal compounds are discussed in detail. Finally, the future prospects of practical applications of transition metal compounds in PIHCs are briefly discussed. [ABSTRACT FROM AUTHOR]

Owing to high power density and long cycle life, micro‐supercapacitors (MSCs) are regarded as a prevalent energy storage unit for miniaturized electronics in modern life. A major bottleneck is achieving enhanced energy density without sacrificing both power density and cycle life. To this end, designing electrodes in a "smart" way has emerged as an effective strategy to achieve a trade‐off between the energy and power densities of MSCs. In the past few years, considerable research efforts have been devoted to exploring new electrode materials for high capacitance, but designing clever configurations for electrodes has rarely been investigated from a structural point of view, which is also important for MSCs within a limited footprint area, in particular. This review article categorizes and arranges these "smart" design strategies of electrodes into three design concepts: layer‐by‐layer, scaffold‐assisted and rolling origami. The corresponding strengths and challenges are comprehensively summarized, and the potential solutions to resolve these challenges are pointed out. Finally, the smart design principle of the electrodes of MSCs and key perspectives for future research in this field are outlined. [ABSTRACT FROM AUTHOR]

Sodium‐ion battery (SIB) is significant for grid‐scale energy storage. However, a large radius of Na ions raises the difficulties of ion intercalation, hindering the electrochemical performance during fast charge/discharge. Conventional strategies to promote rate performance focus on the optimization of ion diffusion. Improving interface capacitive‐like storage by tuning the electrical conductivity of electrodes is also expected to combine the features of the high energy density of batteries and the high power density of capacitors. Inspired by this concept, an oxide‐metal sandwich 3D‐ordered macroporous architecture (3DOM) stands out as a superior anode candidate for high‐rate SIBs. Taking Ni‐TiO2 sandwich 3DOM as a proof‐of‐concept, anatase TiO2 delivers a reversible capacity of 233.3 mAh g−1 in half‐cells and 210.1 mAh g−1 in full‐cells after 100 cycles at 50 mA g−1. At the high charge/discharge rate of 5000 mA g−1, 104.4 mAh g−1 in half‐cells and 68 mAh g−1 in full‐cells can also be obtained with satisfying stability. In‐depth analysis of electrochemical kinetics evidence that the dominated interface capacitive‐like storage enables ultrafast uptaking and releasing of Na‐ions. This understanding between electrical conductivity and rate performance of SIBs is expected to guild future design to realize effective energy storage. [ABSTRACT FROM AUTHOR]

In response to the increased demands of available energy storage, sodium ion batteries (SIBs) appear as promising alternatives to widely used lithium ion batteries. However, because of large radius of Na ions, more complex requirements for the intrinsic properties raise the difficulties in finding a suitable material, in particularly for electrodes with intercalation mechanism. Concerning the principle of designing effective electrodes, the ordering of atomic arrangements should be at the heart in SIBs due to its significant influences on various electrochemical processes, such as ion absorption, ion diffusion, electron diffusion, etc. As proof-of-concept, the state-of-the art TiO2 electrodes with different orderliness of atomic arrangement are achieved through colloidal crystal template method assisted by low-temperature atomic layer deposition and post-heating treatment. The disordering at the surface is benefit for the contribution from surface processes, which is particularly significant to the electrode materials with poorer affinity of transporting ions. Meanwhile, the disordering in bulk results in better ion diffusion, but worse electron transport. Understanding this relationship between atomic orderliness and battery performance is of importance for extending the design principle to some traditional electrodes for highly effective energy storage. [ABSTRACT FROM AUTHOR]

Rechargeable ion batteries have contributed immensely to shaping the modern world and been seriously considered for the efficient storage and utilization of intermittent renewable energies. To fulfill their potential in the future market, superior battery performance of high capacity, great rate capability, and long lifespan is undoubtedly required. In the past decade, along with discovering new electrode materials, the focus has been shifting more and more toward rational electrode designs because the performance is intimately connected to the electrode architectures, particularly their designs at the nanoscale that can alleviate the reliance on the materials' intrinsic nature. The utilization of nanoarchitectured arrays in the design of electrodes has been proven to significantly improve the battery performance. A comprehensive summary of the structural features and fabrications of the nanoarchitectured array electrodes is provided, and some of the latest achievements in the area of both lithium- and sodium-ion batteries are highlighted. Finally, future challenges and opportunities that would allow further development of such advanced electrode configuration are discussed. [ABSTRACT FROM AUTHOR]

Previous studies have shown that gastric tone is inhibited by the electrical stimulation of some parts of the gut. The aims of this study were to investigate the effects of gastric electrical stimulation (GES), duodenal electrical stimulation (DES), ileal electrical stimulation (IES), and colonic electrical stimulation (CES) on gastric tone and the possible mechanism of electrical stimulation on gastric tone. Experiments were performed to study: (1) the effects of the four stimulations (GES, DES, IES, CES) on gastric tone; (2) the role of the nitrergic pathway's involvement in the effect of IES on gastric tone. Each dog was implanted with one pair of gastric, duodenal, ileal, and colonic electrodes and a gastric cannula. A computerized barostat was used to assess gastric tone by measuring the gastric intra-balloon volume. We found that: (1) all methods of stimulation significantly inhibited gastric tone; (2) the percentage of increase in gastric volume was highest with CES and lowest with DES; however, there was no significant difference in the percentage of inhibition among the four stimulations; (3) the inhibitory effect of IES on gastric tone was abolished by intravenous nitric oxide synthase inhibitor. It was concluded that electrical stimulation of the stomach, intestine, or colon with long pulses has an inhibitory effect on gastric tone, and the most effective stimulation is CES. The inhibitory effect is not organ-specific and is unrelated to the distance between the stimulation site and the affected organ. The inhibitory effect of IES on gastric tone is mediated by the nitrergic pathway. [ABSTRACT FROM AUTHOR]

In article number 1502514, Yong Lei and co‐workers present a comprehensive update on the fabrication and utilization of nanoarchitectured array electrodes for rechargeable lithium‐ and sodium‐ion batteries. This advanced electrode design can enhance the battery performances by rapid ion transport in electrolytes, short ion diffusion in electrodes, directional electron transport pathways, large surface area, and high electrode stability. [ABSTRACT FROM AUTHOR]

Attributed to its environmental friendliness, high theoretical energy density, and abundant sodium resource, rechargeable hybrid sodium-air batteries (HSABs) are expected to become a promising pioneer of the new-generation green energy storage device. However, HSABs suffer from the high voltage gap, low energy conversion efficiency, and poor cycle stability due to the low catalytic activity of catalysts caused by the degradation of polymer binders. Herein, hierarchical mesoporous NiO nanosheet arrays grown on carbon papers (CP) (NiO NA@CP) were synthesized by a facile and efficient hydrothermal route and calcination process, which acts as an integrated electrode for HSABs. Compared with traditional air electrodes that contain a polymer binder and conductive carbon, the integrated NiO NA@CP electrode prevents the aggregation of catalysts, improves the electronic conductivity by good electric contact and ensures its robust mechanical stability. In addition, NiO NA@CP electrode with the abundant porosity and large specific area offers plenty of active sites and shortens ion transfer length and rapid mass transport in ORR/OER process, leading to excellent oxygen catalytic activities. HSABs with NiO NA@CP electrode show a low overpotential of 0.65 V, a state-of-the-art power density (7.53 mW cm−2), as well as an excellent cyclability of 170 cycles (over 170 h) at a current density of 0.1 mA cm−2. [ABSTRACT FROM AUTHOR]

The mechanically alloyed (MA) Mg35Ti10−xCrxNi55 (x=5, 7, 9) electrode alloys were investigated for their electrochemical performance. It was found that when the Cr content was low, with the increase of Cr, the maximum discharge capacity decreased gradually, while the cycling capacity retention was improved significantly. X-ray photoelectron spectroscopy (XPS) surface analysis revealed that the Cr content in alloys effectively depressed the oxidation of metallic elements behind the passivation layer, which was built up during corrosion at the surface. Further XPS and Auger electron spectroscopy (AES) studies revealed that on the external side of the surface of Mg35Ti5Cr5Ni55 a multi-component (Cr2O3)k(TiO2)l(NiO)m(Mg(OH)2)n composite passivation layer was formed, which was much thinner (nearly 150 nm) and more compact than the layer formed on the surface of Mg35Ti10Ni55. The corrosion current density Icorr of the alloys decreased also with the augmentation of Cr content. However, Cr in the alloy was found to cause an increase of the reaction resistance at the surface and at the same time a reduction in the surface reaction activty. For the optimum performance of the alloy, the amount of Cr substitution was suggested to be around 5 at.%. At this level of Cr substitution, Icorr is still too high for practical usage. The formation a more compact, less pervious to OH− and electrochemically less active surface passivation layer due to the introduction of Cr is believed to be the main cause for the improvement of the cycling stability, the reduction of exchange current density and the deterioration of surface reaction activity. [Copyright &y& Elsevier]

Graphical abstract Highlights • Novel hybrid nanoporous electrodes were fabricated for efficient hydrogen evolution. • Hydrogen evolution activity was improved though dual-step surface engineering strategy. • Overpotential of 29 mV and Tafel slope of 42 mV per decade were achieved. • DFT theoretical simulations identified the hydrogen evolution mechanism. Abstract The hydrogen evolution reaction (HER) from electrocatalytic water splitting represents an important approach for efficient hydrogen production, in which the HER feasibility relies on electrocatalysts as well as the art of electrode design. Herein, a considerate surface engineering strategy is developed for promoting HER process taking place on nanoporous HER electrodes. Cobalt nanopore arrays (CoNPA) are fabricated as the representative nanoporous HER electrode. Then an ultrathin titanium dioxide (TiO 2) with optimized thickness is conformally coated onto CoNPA for improving the wettability in order to expose more active sites, followed by a well-dispersed platinum (Pt) nanoparticles with an ultralow mass loading (ca. 54 μg cm−2) anchored on TiO 2 layer for enhancing the HER activity. The advanced features of nanoporous architecture in combination with the synergistic contribution from ultrathin TiO 2 layer and well-dispersed Pt nanoparticles enable CoNPA@TiO 2 @Pt electrode exhibit outstanding HER performance in alkaline conditions, i.e. , an overpotential of 29 mV needed to reach the catalytic current density of 10 mA cm−2 and long-termed performance as well as structure stability. Not limited to the HER electrodes, the similar strategy is also expected to be further applied to the rational design and nanoengineering of electrodes for other electrochemical energy conversion and storage devices. [ABSTRACT FROM AUTHOR]

Abstract An original electrode, 3D TiO 2 @C core/shell nanobelt arrays with controllable carbon coating thickness, was successfully constructed in this work. The 3D TiO 2 nanobelts were directly grown on Ti foil, and then were coated with a layer of metal-organic framework (MOF). After thermal annealing, a porous carbon layer with tunable thickness was coated onto the 3D TiO 2 nanobelts through changing the MOF thickness. The as-prepared TiO 2 @C-2 h with 5-nm-thick carbon layer presented an excellent discharge capacity of 210.5 mAh g−1 after 100 cycles at a current density of 50 mA g−1, which is 38% higher than that of pure TiO 2 electrode without carbon coating. Moreover, it can maintain a reversible capacity of 141 mAh g−1 after 1000 cycles at a current density of 200 mA g−1, and a good rate performance with 33% of capacity retention when the current density increasing from 50 to 5000 mA g−1. All the results indicate that the TiO 2 @C core/shell nanobelt array is a promising anode for sodium-ion batteries. Highlights • 3D TiO 2 nanobelt arrays possess short ion transport distance. • Coating of porous carbon layer can solve low rate capability and poor stability. • Carbon coating can be tuned by MOF thickness to get optimal performance. • Ideal 3D TiO 2 @C nanobelt-SIB exhibit superior reversible capacity and rate capability. [ABSTRACT FROM AUTHOR]