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Aqueous zinc-ion batteries (AZIBs) have been extensively recognized as the most viable large-scale energy storage devices due to their low cost, ecofriendliness, and high safety. Nevertheless, zinc anodes in conventional aqueous electrolytes suffer from harmful reactions, including zinc dendrites, hydrogen evolution reaction, and corrosion, resulting in a short cycle life of AZIBs. In recent years, versatile strategies have been performed to address these problems, among which engineering the electrolyte additive is regarded as a promising approach thanks to its advantages of simplicity and operability. Up to now, a great deal of work on electrolyte additives has been published; therefore, an in-depth and fundamental understanding of the mechanisms of additives is urgently needed. In this review, we comprehensively overview the functional role of the electrolyte additive in AZIBs, including regulating the solvation structure, altering the H-bond network, forming an adsorption layer, generating an electrostatic shielding effect, and constructing a solid electrolyte interphase. Lastly, some prospects for the future development of additives for advanced AZIBs are also suggested in this review.

Unraveling the catalyst surface structure and behavior during reactions is essential for both mechanistic understanding and performance optimization. Here we report a phenomenon of facet-dependent surface restructuring intrinsic to β-Ni(OH)2catalysts during oxygen evolution reaction (OER), discovered by the correlative ex situand operandocharacterization. The ex situstudy after OER reveals β-Ni(OH)2restructuring at the edge facets to form nanoporous Ni1–xO, which is Ni deficient containing Ni3+species. Operandoliquid transmission electron microscopy (TEM) and Raman spectroscopy further identify the active role of the intermediate β-NiOOH phase in both the OER catalysis and Ni1–xO formation, pinpointing the complete surface restructuring pathway. Such surface restructuring is shown to effectively increase the exposed active sites, accelerate Ni oxidation kinetics, and optimize *OH intermediate bonding energy toward fast OER kinetics, which leads to an extraordinary activity enhancement of ∼16-fold. Facilitated by such a self-activation process, the specially prepared β-Ni(OH)2with larger edge facets exhibits a 470-fold current enhancement than that of the benchmark IrO2, demonstrating a promising way to optimize metal-(oxy)hydroxide-based catalysts.

Intermetallic compounds, featuring atomically ordered structures, have emerged as a class of promising electrocatalysts for fuel cells. However, it remains a formidable challenge to controllably synthesize Pt-based intermetallics during the essential high-temperature annealing process as well as stabilize the nanoparticles (NPs) during the electrocatalytic process. Herein, we demonstrated a Ketjen black supported intermetallic Pt3Ti nanocatalyst coupled with amorphous TiOxspecies (Pt3Ti-TiOx/KB). The TiOxcan not only confine Pt3Ti NPs during the synthesis and electrocatalytic process by a strong metal–oxide interaction but also promote the water dissociation for generating more OH species, thus facilitating the conversion of COad. The Pt3Ti-TiOx/KB showed a significantly enhanced mass activity (2.15 A mgPt–1) for the methanol oxidation reaction, compared with Pt3Ti/KB and Pt/C, and presented an impressively high mass activity retention (∼71%) after the durability test. This work provides an effective strategy of coupling Pt-based intermetallics with functional oxides for developing highly performed electrocatalysts.

Intermetallic compounds have emerged as a class of promising electrocatalysts for fuel cells; however, it is still a great challenge to synthesize monodisperse and small intermetallic phases by an economical and scalable method. Herein, we demonstrate a generally applicable solid-phase seed-mediated diffusion strategy for controllable synthesis of ordered L10-PtM (M = Mn, Fe, Co, and Zn) nanoparticles, where the preprepared monodispersed Pt seeds are used as the growth sites. The freeze-drying procedure produces monodisperse metal precursors on Pt/C, and the subsequent annealing process in a H2/Ar atmosphere obtains highly dispersed and ultrasmall PtM intermetallic nanocrystals (∼3 nm) on carbon supports. More importantly, such a strategy is also applicable to the preparation of a high-loaded PtMn intermetallic catalyst (50 wt %). Taking PtMn/C catalysts as examples, we illustrate their synthetic details and formation mechanism of the desired ordered phases. This approach eliminates the need for energy-consuming filtering and washing procedures, which makes it very promising for large-scale production.

Aqueous zinc-ion batteries (AZIBs) have attracted attention for their low cost and environmental friendliness. Unfortunately, commercialization has been hampered by several problems with dendrite growth and side reactions. Herein, we select sodium tartrate (TA-Na) as a dual-functional electrolyte additive to enhance the reversibility of AZIBs. The tartrate anions are preferentially adsorbed on the Zn surface, and then the highly nucleophilic carboxylate will coordinate with Zn2+to promote the desolvation of [Zn(H2O)6]2+, leading to uniform Zn deposition on the beneficial (002) plane and inhibiting side reactions and dendrite growth. Consequently, the Zn|Zn cells show a long-term cycling stability of over 1500 cycles at 0.5 mA cm–2. Moreover, the Ta-Na additive improves the performance of Zn||MnO2full cells, evidenced by a cycling life of 1000 cycles at 1 A g–1under practical conditions with a limited Zn anode (negative/positive capacity ratio of 10/1) and controlled electrolyte (electrolyte/capacity ratio of 20 μL mAh–1).

The fuel cell hybrid powertrain is a potential power supply system for fuel cell vehicles. The underlying problem is that the fuel cell vehicles encounter exhaustive hydrogen consumption. To effectively manage hydrogen consumption, the aim is to propose fuel cell city bus power and control system. The underlying idea is to determine the target power of fuel cell through simulation study on fuel cell and battery energy management strategy and road test verifications. A half-power prediction energy management strategy is implemented to predict the target power of the fuel cell in the current time step based on the demand power of the vehicle and the state of charge (SOC) of the battery in the previous time steps. This offers better understanding of the correlation between fuel cell power and vehicle drive cycle for enabling effective power supply management. The research results show that the half-power prediction energy management strategy effectively reduces the hydrogen consumption of the vehicle by 7.1% and the number of battery cycle by 6.0%, compared to the stepped management strategy of battery SOC. When applied to a 12-m fuel cell city bus—F12, specially designed and manufactured for the Winter Olympic Games in 2022—the fuel economy of 3.7 kg/100 km is achieved in urban road conditions. This study lays a foundation for providing the powertrain configuration and energy management strategy of fuel cell city bus.

The development of the electrocatalyst-integrated electrodes with HER/OER bifunctional activity is desirable to reduce the cost and simplify the system of the practical water electrolyzers. Herein, we construct a new type of Ni3Fe1–xCrx(0 ≤ x< 0.3) intermetallic integrated electrodes for overall water splitting via an ultrafast carbothermal shock method. The obtained Ni3Fe0.9Cr0.1/CACC electrode exhibits the optimum performance among all developed electrocatalyst electrodes in this work, and the overpotential is merely 239 mV for OER and 128 mV for HER at 10 mA cm–2. In addition, the Ni3Fe0.9Cr0.1/CACC electrode shows excellent durability during both OER and HER stability tests at a high current density of 100 mA cm–2. An electrolyzer, which was assembled with Ni3Fe0.9Cr0.1/CACC electrodes as both the anode and cathode, operates with a low cell voltage of 1.59 V at 10 mA cm–2. It has been found that the impressive OER activity of Ni3Fe0.9Cr0.1nanoparticles (NPs) can be ascribed to the stimulative formation of the OER-active Ni3+/Fe3+species by the substituted Cr, while the enhanced HER activity is caused by the Cr substitution, which decreases the water dissociation energy barrier. This work provides an ultrafast and facile strategy to develop electrocatalyst-integrated electrodes with low cost and impressive HER/OER bifunctional performance for overall water splitting.

The development of efficient and cost-effective metal-free electrocatalysts for oxygen reduction reaction (ORR) has become crucial for electrochemical energy systems. However, reasonably validating and precisely regulating the active sites for designing optimized materials are still challenging. Herein, we report a precise and controllable tandem strategy to boost the ORR activity based on metal-free covalent organic frameworks (MFCOFs) comprising imine-N, thiophene-S, or triazine-N. Among these MFCOFs, post-tandem BTT-TAT-COF structure displayed a more positive catalytic capability and excellent electrochemical stability, indicating that the synergistic catalysis of multiple active sites induced the ORR catalytic activity through the conjugated skeleton of the structure. Density-functional theory calculations suggest that the series-connected backbone contained highly effective electrocatalytic active centers and provided synergistic catalysis. More importantly, this strategy highlights new opportunities for the advancement of efficient COF-based metal-free ORR catalysts.

The accurate assessment of battery health is crucial for maximizing the performance and lifespan of lithium-ion batteries. In this paper, an ensemble model based on a two-dimensional multi-channel convolutional neural network is proposed to predict the maximum usable capacity of lithium-ion batteries. First, based on the charge–discharge process, the characteristic-derived lines of the capacity–voltage (Q–V) curve are extracted. Next, the Gramian angular summation field (GASF) is employed to convert one-dimensional time series data into image matrices, with the aim of preserving temporal characteristics. Finally, the paper discusses the impact of 2D matrix size on prediction results and introduces the use of a 2D multi-channel ensemble model for the unsupervised recognition and extraction of battery decline information from images, marking the first time this approach has been utilized. The experimental results demonstrate that the proposed method effectively captures battery degradation patterns from multiple perspectives. The average mean absolute percentage error of 1.95% and root mean square error of 1.41% on the verified batteries indicate the robustness and generalizability of the approach.

Organic material holds immense potential for Li-ion batteries (LIBs) due to their eco-friendly nature, high structural designability, abundant sources, and high theoretical capacity. However, the limited redox-active sites, low electronic conductivity, sluggish ionic diffusion, and high solubility hinder their practical application. Here, we reported the use of a linear polymer called poly(naphthalenetetracarboxylic dianhydride-pyrene-4,5,9,10-tetraone)-coated graphene nanosheets (NPT/rGO) as a cathode material for LIBs. The NPT polymer has a rotation angle of approximately 63° between each plane, which helps in exposing the active sites and preventing structural pulverization during cycling. The highly conjugated skeleton of the polymer, along with graphene, forms a synergistic effect through a π–π interaction. This combination enhances the conductivity and restricts solubility. Additionally, the linear structure of NPT and the two-dimensional rGO substrates work together to enhance charge transfer and ion diffusion rates, resulting in faster reaction kinetics. Consequently, NPT/rGO exhibits excellent electrochemical performance in terms of high capacity, superior cyclic stability, and good rate capability for LIBs. Moreover, through the combination of experimental investigations and theoretical simulations, a multiple electron reaction mechanism, an efficient Li-ion storage behavior, and a reversible dynamic evolution have been revealed. This study introduces a rational molecular design approach to enhance the electrochemical performance of polyimide derivatives, thereby contributing to the advancement of cutting-edge organic electrode materials for LIBs.

Aqueous aluminum-ion batteries (AAIBs) are considered as a promising alternative to lithium-ion batteries due to their large theoretical capacity, high safety, and low cost. However, the uneven deposition, hydrogen evolution reaction (HER), and corrosion during cycling impede the development of AAIBs, especially under a harsh environment. Here, a hydrated eutectic electrolyte (AATH40) composed of Al(OTf)3, acetonitrile (AN), triethyl phosphate (TEP), and H2O was designed to improve the electrochemical performance of AAIBs in a wide temperature range. The combination of molecular dynamics simulations and spectroscopy analysis reveals that AATH40 has a less-water-solvated structure [Al(AN)2(TEP)(OTf)2(H2O)]3+, which effectively inhibits side reactions, decreases the freezing point, and extends the electrochemical window of the electrolyte. Furthermore, the formation of a solid electrolyte interface, which effectively inhibits HER and corrosion, has been demonstrated by X-ray photoelectron spectroscopy, X-ray diffraction tests, and in situ differential electrochemical mass spectrometry. Additionally, operandosynchrotron Fourier transform infrared spectroscopy and electrochemical quartz crystal microbalance with dissipation monitoring reveal a three-electron storage mechanism for the Al//polyaniline full cells. Consequently, AAIBs with this electrolyte exhibit improved cycling stability within the temperature range of −10–50 °C. This present study introduces a promising methodology for designing electrolytes suitable for low-cost, safe, and stable AAIBs over a wide temperature range.

Perovskite oxides have attracted much attention for enabling the oxygen-evolution reaction (OER) over the past decades. Nevertheless, their poor conductivity is still a barrier hindering their use. Herein, we report a catalyst prototype of Co-based antiperovskite nitrides CuNCo3–xVx(0 ≤ x≤ 1) to be a highly effective OER electrocatalyst. The synthesized CuNCo3–xVxexhibits greatly enhanced activity and stability toward the OER in alkaline medium. The CuNCo2.4V0.6shows a mere 235 mV of overpotential to reach 10 mA cm–2, which is comparable to that of Ir/C (232 mV). More importantly, the CuNCo2.4V0.6is more durable than the conventional Ir/C catalyst. The CuNCo2.4V0.6catalyst enabled a Zn–air battery to exhibit a cycle life of 143 h with a much higher cell efficiency. The V-substituted CuNCo2.4V0.6provides a higher content of the desirable Co3+species in the post-OER catalyst, which ensures a high activity over a long-term operation. With these enhanced effects enabled by the compositional flexibility of CuNCo3–xVxantiperovskite nitride, a feasible strategy for optimizing an electrocatalyst with tunable properties is provided.

There are crucial demands for high power density and long-term cycling performance of Li-ion batteries (LIBs), and the development of stable electrode material operating at high current densities still remains a challenge. Here we develop a novel strategy for the synthesis of flexible N-doped carbon nanofiber/CoFe2O4film (CoFe2O4@N-CNF) with a double-layer carbon protection by electrospinning, which possesses stable carbon shell and honeycomb-like core with CoFe2O4nanosheets embedded into conductive and interconnected carbon nanosheets. The unique structure is beneficial for providing robust structural stability upon long-term cycling, and offering nitrogen-rich interconnected mesoporous and conductive carbon matrix for fast charge and ion transport. As a consequence, the optimized CoFe2O4@N-CNF exhibits a high reversible capacity of 858 mAh g−1at 0.1 A g−1, excellent rate capability (306 mAh g−1at 30 A g−1), and superior cycling stability up to 10,000 cycles with almost no capacity loss at 10 A g−1. We believe that this proposed methodology has a profound impact on drastic improvements of various flexible energy storage devices.

Organic compounds exhibit great potential as sustainable, tailorable, and environmentally friendly electrode materials for rechargeable batteries. However, the intrinsic defects of organic electrodes, including solubility, low ionic conductivity, and restricted electroactivity sites, will inevitably decrease the cycling life and capacity. We herein designed and prepared nanostructured porous polymers (NPP) with a simple one-pot method to overcome the above defects. Theoretical calculations and experimental results demonstrate that the as-synthesized NPP exhibited low volume expansion, molecular–structural distortion, and a gradual function activation process during cycling, thus exhibiting superior, high, and durable lithium storage. The gradual molecular distortion during the lithium storage processes provides more redox-active sites for Li storage, increasing the Li-storage capacity. Ex situ spectrum studies reveal the redox reaction mechanism of Li storage and demonstrate a gradual activation process during the repeated charging/discharging until the full storage of 18 Li ions is achieved. Additionally, a real-time observation on the NPP anode by in situ transmission electron microscope reveals a slight volume expansion during the repeating lithiation and delithiation processes, ensuring its structural integrity during cycling. This quantitative work for high-durability lithium storage could be of immediate benefit for designing organic electrode materials.

The rapid detection and accurate identification of the safety state of lithium-ion battery systems have become the main bottleneck of the large-scale deployment of electric vehicles. To solve this problem, an intelligent fault diagnosis method based on deep learning is proposed. In order to avoid the influence of noise signals on fault identification, firstly, the high-frequency noise signal is filtered by the empirical mode decomposition algorithm and Pearson correlation coefficient. Secondly, an improved voltage data processing method is proposed for the first time, which can expand the relative voltage difference between the monomer voltages in the system, facilitate CNN to quickly extract the characteristic parameters of voltage data. Thirdly, in order to meet the requirements that the training model of CNN needs a large number of samples, the method of expanding the number of samples by using a sliding window is proposed. Finally, samples are input into the trained CNN model for fault type identification, and the results show that the method has high accuracy and timeliness. In summary, the proposed method is feasible, which provides the theoretical basis for the battery system's future fault hierarchical management strategy.

Decaborane (B10H14) obtains a high energy density, attaining approximately 11455 Wh kg-1. Herein, we studied the fuel cell power source based on B10H14. A proof-of-concept fuel cell feeding on B10H14obtains a peak power density of 110.82 mW cm-2, which is comparable to the common Direct Methanol Fuel Cells (DMFCs). Besides, the new fuel cell exhibits an open circuit voltage (OCV) of 1.098V, much higher than that of DMFCs and Direct Liquid Fuel Cells (DLFCs) feeding on N2H4, CH3OCH3, HCOOH, etc. It implies that the common Nafion membrane is good enough to effectively suppress the fuel crossover, which is a long pending problem for DMFCs and other DLFCs. It opens a new way in utilizing the chemical energy of B10H14, and develops a new type of fuel cell, which is promising for application in high specific energy mobile power, long endurance unmanned aerial vehicles, etc.

While substantial electrocatalysts have been proposed and efficiently catalyze CO2to multiple products, mass transport is becoming a major constraint to further improve the performance of CO2electrochemical reduction reaction (CO2ERR). Gas diffusion electrode (GDE) technique has been identified as an effective way to overcome the confined mass transfer of CO2. While many research efforts have focused on the catalyst layer (CL), considerably fewer efforts have focused on the gas diffusion layer (GDL), the support and substrate of GDE. Herein, we studied the effect of the GDL on the performance of phthalocyanine cobalt (CoPc)-based GDE to catalyze CO2to CO with a special emphasis on the hydrophilicity, porosity, and wettability. We demonstrate a facile and reproducible method of PTFE impregnation to tune the hydrophobicity and pore characteristics of GDL, to enhance CO2ERR. Using a proper designed GDL as the substrate, the CoPc-based GDE achieves a high current density of 321.7 mA cm−2and Faradaic efficiency for CO of 98.4% at a cathode potential of −1.2 V (vs RHE), representing the highest performance of CoPc-based GDEs reported in the literature.

Antimony-based materials are considered as promising anodes for potassium ion batteries due to their high theoretical capacity and low electrode potential. However, the aggregation and bulk expansion of Sb particles in cycling will cause capacity attenuation and poor rate performance. In this paper, Sb nanoplates were designed to be embedded in flexible porous N-dopped carbon nanofibers (Sb@PCNFs) by a simple electrospinning deposition (ESD) method. In this structural design, Sb nanoplates of high capacity were employed as active materials, N-dopped carbon nanofibers were used to improve conductivity and structural stability. The introduction of pore-forming agent enables the nanofibers to possess porous structure, thus buffering the huge volume change and promoting the transfer of electrolyte/ions. More importantly, the freestanding film can be directly used as a working electrode, reducing the redundancy in the battery and the cost. Benefitting from the favorable structure, the freestanding flexible Sb@PCNFs electrode shows excellent potassium storage performance with a capacity of 314 mAh/g after 2000 cycles at 500 mA/g. This strategy of employing active material with high capacity in porous and conductive flexible nanofibers represents an effective method of achieving binder-free electrode with good electrochemical performance towards wearable energy storage devices.

High volumetric capacity and durability anode materials for sodium ion batteries have been urgently required for practical applications. Herein, we reported a Sn-pillared pyknotic graphene conductive network with high-level N-doping. This densely stacked block offers high volumetric Na-ion storage capacity, rapid electrochemical reaction kinetics, and robust structural stability during cycling owing to the high capacity component (metallic Sn ≈847 mAh g–1), high tap density (≈2.63 g cm–3), high conductivity (N doping ≈5 at. %), and strong spatially confined and pillared structure. Moreover, theoretical simulations have indicated that the charge accumulation around the N-doped region is more pronounced compared to the pristine one, and electrons accumulate around the N atom while loss occurs at the Na atom. These studies also suggest that it might possibly contribute to higher conductivity and stronger electrophilic reactivity, thereby resulting in enhanced Na-ion storage performance. As a result, the as-obtained electrode material exhibits competitive volumetric capacity (1462 mAh cm–3at 0.1 A g–1), cycling performance (1207 mAh cm–3after 100 cycles), and promising rate behavior simultaneously.

Direct liquid fuel cells (DLFCs) are promising candidates for portable applications, because they have high energy density which means long runtime, high energy efficiency, and don't require time-consuming recharging. At present, several types of DLFCs have been invented such as Direct Methanol Fuel Cells (DMFCs), Direct Formic Acid Fuel Cells (DFAFCs), Direct Sodium Borohydride Fuel Cells (DSBFCs), Direct Hydrazine Fuel Cells (DHFCs) and so on. In this work, we propose a novel direct liquid fuel cell feeding on oxalyl dihydrazide which presents as solid power at room temperature and can be easily dissolved in alkali solution, without any emitting toxic gases. Several potential anode catalysts such as Pt/C, PtRu/C and Au/C are evaluated using a three-electrode cell. The results show that Pt/C is more suitable for the electrochemical oxidation of oxalyl dihydrazide than PtRu/C and Au/C. Using Pt/C as anode catalyst, we designed and fabricated two types of Membrane Electrode Assemblies (MEAs) of different structure, one-catalyst-layer MEA (MEA-1CL) and two-catalyst-layer MEA (MEA-2CL). The single cell tests show MEA-2CL obtain higher I-V performance.

Hierarchical hybrid heteroarchitectures possess attractive structural/compositional merits for lithium‐ion batteries (LIBs). Herein, a facile yet in situ growth strategy is proposed to scalably synthesize hierarchical porous ZnO/ZnFe2O4hybrid nanofibers (NFs) with robust core/shell heterostructure toward LIBs. In such hybrids, 2D ZnFe2O4nanosheets (NSs) are uniformly decorated on single‐crystalline ZnO core NFs, thereby affording more exposed active sites, a fast ion diffusion kinetic, and structural stability of electrodes during repeated cycling. As a result, benefiting from the unique hierarchical porous core/shell architecture and synergistic effects between the stable substrate of ZnO NFs and high‐capacity promoter of ZnFe2O4NSs, the optimized ZnO/ZnFe2O4hybrid as an anode for LIBs delivers a large reversible capacity of ≈688 mAh g−1at 0.1 A g−1, high rate capability (≈288 mAh g−1at 2.0 A g−1), and remarkable cyclability (≈491 mAh g−1even over 250 cycles at 0.5 A g−1) for efficient lithium storage. This work highlights the rational design of a hierarchical architecture with a stable substrate and high‐capacity phases for next‐generation energy storage applications. Hierarchical porous ZnO/ZnFe2O4hybrid nanofibers (NFs) with robust core/shell heterostructure are smartly designed and exhibit efficient lithium storage in terms of reversible apacity, rate property, and cyclability as competitive anodes for advanced Li‐ion batteries.

Organic compounds are promising electrode materials because of their resource sustainability, environmental friendliness, and highly tailorable properties. The porous conjugated polymer shows great potential as an electrode material for its tunable redox nature, conjugated skeleton, and porous structure. Herein, a novel conjugated porous polymer, polydiaminophenylsulfone–triazine, was synthesized by a simple nucleophilic substitution reaction. The conjugated structure and triazine ring can improve the conductivity, charge-transfer efficiency, and physicochemical stability. Also, the porous polymeric framework shows a large specific surface area and high porosity, providing a large contact area with electrolytes and reducing diffusion distance. The polymer demonstrates highly stable cycling performance and good rate capability as an anode for lithium-ion batteries, suggesting a promising strategy to design a competitive electrode material.

In this work, a novel bamboo-like carbon nanotubes@Sn4P3@carbon (BLCNTs@Sn4P3@C) coaxial nanotubes are designed and prepared using a newly developed hydrothermal method followed by a phophidation process. The prepared Sn4P3nanoparticles are uniformly coated and wrapped on the one-dimensional (1D) bamboo-like CNTs, which is covered by a uniform carbon layer to form a sandwich-like structure with Sn4P3in between. The inner CNT and outer carbon can effectively maintain the structural stability and serve as the good electron conductors. Additionally, the outer carbon coating layer can effectively keep BLCNTs@Sn4P3@C nanotubes separate each other, preventing aggregation of Sn4P3during charge/discharge when this material is used as anode for sodium ion batteries. The anode of BLCNTs@Sn4P3@C shows excellent reversible capacity and a long cycling of over 2000 cycles. The unique design of coaxial nanotubes is greatly beneficial to the electrochemical performance of Sn4P3for sodium ion storage.

N, O co-doped graphene layered block (NOGB) was prepared as sulfur host for lithium–sulfur batteries.The NOGB/S shows good rate performance due to robust electrochemical kinetics.The strong physicochemical confinement leads to an improved cycling stability.