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An integrated composite architecture composed of N/P codoped porous carbon sheets and embedded Ni2P NPs (Ni2P⊂N/P-CNS) was synthesized by a self-template strategy and demonstrated superior electrochemical performance as alkali ion battery anode.

Immobilizing primary electroactive nanomaterials in porous carbon matrix is an effective approach for boosting the electrochemical performance of potassium-ion batteries (PIBs) because of the synergy among functional components. Herein, an integrated hybrid architecture composed of ultrathin Cu3P nanoparticles (~20 nm) confined in porous carbon nanosheets (Cu3P⊂NPCSs) as a new anode material for PIBs is synthesized through a rational self-designed self-templating strategy. Benefiting from the unique structural advantages including more active heterointerfacial sites, intimate and stable electrical contact, effectively relieved volume change, and rapid K+ ion migration, the Cu3P⊂NPCSs indicate excellent potassium-storage performance involving high reversible capacity, exceptional rate capability, and cycling stability. Moreover, the strong adsorption of K+ ions and fast potassium-ion reaction kinetics in Cu3P⊂NPCSs is verified by the theoretical calculation investigation. Noted, the intercalation mechanism of Cu3P to store potassium ions is, for the first time, clearly confirmed during the electrochemical process by a series of advanced characterization techniques.

Hybrid architectures composed of NiSe2/FeSe2 heterostructured nanoparticles supported on rGO were synthesized through a facile self-templating strategy, and exhibited excellent electrocatalytic performance for overall water splitting.

The practical application of lithium-sulfur (Li-S) batteries is greatly hindered by the shuttle effect of dissolved polysulfides in the sulfur cathode and the severe dendritic growth in the lithium anode. Adopting one type of effective host with dual-functions including both inhibiting polysulfide dissolution and regulating Li plating/stripping, is recently an emerging research highlight in Li-S battery. This review focuses on such dual-functional hosts and systematically summarizes the recent research progress and application scenarios. Firstly, this review briefly describes the stubborn issues in Li-S battery operations and the sophisticated counter measurements over the challenges by dual-functional behaviors. Then, the latest advances on dual-functional hosts for both cathode and anode in Li-S full cells are catalogued as species, including metal chalcogenides, metal carbides, metal nitrides, heterojunctions, and the possible mechanisms during the process. Besides, we also outlined the theoretical calculation tools for the dual-functional host based on the first principles. Finally, several sound perspectives are also rationally proposed for fundamental research and practical development as guidelines.

Toward the well-explored lithium-sulfur (Li-S) catalytic chemistry, the slow adsorption-migration-conversion kinetics of lithium polysulfides on catalytic materials and Li

The exploitation of new sulfiphilic and catalytic materials is considered as the promising strategy to overcome severe shuttle effect and sluggish kinetics conversion of lithium polysulfides within lithium-sulfur batteries. Herein, we design and fabricate monodisperse VN ultrafine nanocrystals immobilized on nitrogen-doped carbon hybrid nanosheets (VN@NCSs) via an one-step in-situ self-template and self-reduction strategy, which simultaneously promotes the interaction with polysulfides and the kinetics of the sulfur conversion reactions demonstrated by experimental and theoretical results. By virtue of the multifunctional structural features of VN@NCSs, the cell with ultrathin VN@NCSs (only 5 µm thickness) modified separator indicates improved electrochemical performances with long cycling stability over 1,000 cycles at 2 C with only 0.041% capacity decay per cycle and excellent rate capability (787.6 mAh·g−1 at 10 C). Importantly, it delivers an areal reversible capacity of 3.71 mAh·cm−2 accompanied by robust cycling life.

The employment of catalytic materials is regarded as the most desirable strategy to cope with sluggish kinetics of lithium polysulfides (LiPSs) transformation and severe shuttle effect within lithium-sulfur batteries (LSBs). Single-atom catalysts (SACs) with 100% atom-utilization possess competitive advantages to serve as both anchoring and electrocatalytic centers for LiPSs. However, it's still a great challenge due to the insufficiency of facile synthetic strategy and ambiguity of the structure-property relationships. Herein, a novel kind of tungsten (W) SAC immobilized on nitrogen-doped graphene (W/NG) with a unique W-O2N2-C coordination configuration and a high W loading of 8.6 wt% is first proposed via a self-template and self-reduction strategy. The special local coordination environment of W atom endows the W/NG with elevated LiPSs adsorption ability and catalytic activity evidenced by combination of experimental and theoretical studies. Impressively, LSBs equipped with W/NG modified separator manifest greatly improved electrochemical performances with high cycling stability over 1000 cycles and ultrahigh rate capability. Moreover, it indicates high areal capacity of 6.24 mAh cm-2 with robust cycling life at a high sulfur mass loading of 8.3 mg cm-2 .

Rechargeable aqueous zinc-ion batteries (AZIBs) have captured a surge of interest in recent years as a promising alternative for scalable energy storage applications owing to the intrinsic safety, affordability, environmental benignity, and impressive electrochemical performance. Despite the facilitated development of this technology by many investigations, however, its smooth implementation is still plagued by inadequate energy density and undesirable life span, which calls for an efficient and controllable cathode storage chemistry. Here, this review focuses on the key bottlenecks by offering a comprehensive summary of representative cathode materials and comparatively analyzing their structural features and electrochemical properties. Then, we critically present several feasible electrode design strategies to guide future research activities from a fundamental perspective for high-energy-density and durable cathode materials mainly in terms of interlayer regulation, defect engineering, multiple redox reactions, activated two-electron reactions, and electrochemical activation and conversion. Finally, we outline the remaining challenges and future perspectives of developing high-performance AZIBs.

Lithium (Li) metal is a “superstar” among all the anode materials for lithium-ion batteries (LIBs) owing to its low electrochemical potential, high theoretical specific capacity, low density, etc. The inherent issues of Li-metal anodes including high chemical activity, uncontrollable growth of Li dendrites, large volume changes, and unstable solid electrolyte interphase (SEI) have been gradually improved in the past several years. However, most of the previous study on Li-metal anodes is performed at room temperature under inert atmosphere. The stability and behavior of Li-metal anode in extreme conditions such as air, water, and high/low temperatures are easy to be ignored. Improving the stability of Li-metal anodes in extreme conditions is meaningful for constructing safe, long-cycling, low-cost, and high-energy Li-metal batteries in all working conditions. Tremendous work has been conducted to enable stable Li-metal anodes in extreme conditions recently. Here we carefully present a review for stable Li-metal anodes in extreme conditions. The backgrounds of Li-metal anodes and strategies for achieving stable Li-metal anodes in extreme conditions are carefully summarized. Meanwhile, we proposed some outlooks and perspectives. We hope this review can make more researchers pay attention to Li-metal anodes in extreme conditions.

Transition−metal oxides are considered to be a promising anode material for lithium−ion batteries (LIBs) due to their high capacities, low cost, and ease of synthesis. Herein, a hybrid nanosheet composed of uniform MoO2 nanoparticles (NPs) homogeneously immobilized on the reduced graphene oxide nanosheets (MoO2 NP@rGO) is first synthesized by a self-templating and subsequent calcination treatment. The unique two-dimensional hybridnanosheets provides several merits. rGO can be used as a favorable support for the loading of electrochemically active MoO2 NPs. Meanwhile, MoO2 NPs can effectively prevent the stacking of the rGO. The effective combination of MoO2 NPs and rGO nanosheets furnish additional electrochemically interfacial active sites for extra lithium ion storage. Noticeably, the as-fabricated hybrid nanosheets deliver a reversible capacity of 641 mAh/g after 350 cycles at a current density of 1000 mA/g with a good rate capability. The greatly enhanced lithium storage properties of MoO2 NP@rGO indicate the importance of elaborate construction of novel hybrid hierarchical structures.

Developing cost-effective, efficient and bifunctional electrocatalysts is vital for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) application. The catalytic activity of electrocatalysts could be optimized by reasonable electronic structure regulation and increasing active sites. Herein, we report the design and fabrication of Mo-doped nickel sulfide/hydroxide heterostructures (Mo-NiS/Ni(OH)2) as a multisite water splitting catalyst via straightforward solvothermal and in-situ growth strategy. Based on foreign metal doping and interface interaction, the electronic conductivity of heterostructures is improved and the charge transfer kinetics across the interface is promoted, which are demonstrated by the theoretical calculations. Mo-NiS/Ni(OH)2 electrocatalyst is endowed with high electrocatalytic performance for water splitting and remarkable durability in alkaline electrolyte. It exhibits the low overpotential of 186 and 74 mV at 10 mA·cm−2 for OER and HER, respectively. Importantly, after continuously working for 50 h, the current densities of HER and OER both show negligible degeneration. Even, the resulting Mo-NiS/Ni(OH)2 better catalyzes water splitting, yielding a current density of 10 mA·cm−2 at a cell voltage of 1.5 V and outperforming Pt/C-IrO2 couple (1.53 V). This result demonstrates that transition metal doping and heterogeneous interface engineering are useful means for conventional catalyst design.

Titanium dioxide (TiO2) has been investigated broadly as a stable, safe, and cheap anode material for sodium-ion batteries in recent years. However, the poor electronic conductivity and inherent sluggish sodium ion diffusion hinder its practical applications. Herein, a self-template and in situ vulcanization strategy is developed to synthesize self-supported hybrid nanotube arrays composed of nitrogen/sulfur-codoped carbon coated sulfur-doped TiO2 nanotubes (S-TiO2@NS-C) starting from H2Ti2O5·H2O nanoarrays. The S-TiO2@NS-C composite with one-dimensional nano-sized subunits integrates several merits. Specifically, sulfur doping strongly improves the Na+ storage ability of TiO2@C-N nanotubes by narrowing the bandgap of original TiO2. Originating from the nanoarrays structures built from hollow nanotubes, carbon layer and sulfur doping, the sluggish Na+ insertion/extraction kinetics is effectively improved and the volume variation of the electrode material is significantly alleviated. As a result, the S-TiO2@NS-C nanoarrays present efficient sodium storage properties. The greatly improved sodium storage performances of S-TiO2@NS-C nanoarrays confirm the importance of rational engineering and synthesis of hollow array architectures with higher complexity.

Lithium–sulfur batteries (LSBs) are regarded as a competitive next-generation energy storage device. However, their practical performance is seriously restricted due to the undesired polysulfides shuttling. Herein, a multifunctional interlayer composed of paper-derived carbon (PC) scaffold, Fe3O4 nanoparticles, graphene, and graphite sheets is designed for applications in LSBs. The porous PC skeleton formed by the interweaving long-fibers not only facilitates fast transfer of Li ions and electrons but also provides a physical barrier for the polysulfide shuttling. The secondary Fe3O4@graphene component can reduce the polarization, boost the attachment of polysulfides, and promote the charging-discharging kinetics. The outer graphitic sheets layers benefit the interfacial electrochemistry and the utilization of S-containing species. The efficient obstruction of polysulfides diffusion is further witnessed via in situ ultraviolet-visible characterization and first-principles simulations. When 73% sulfur/commercial acetylene black is used as the cathode, the cell exhibits excellent capacity retention with high capacities at 0.5 C for 1000 cycles and even up to 10 C for 500 cycles, an ultrahigh rate capability up to 10 C (478 mAh g−1), and a high areal-sulfur loading of 8.05 mg cm−2. The strategy paves the way for developing multifunctional composites for LSBs with superior performance.

The oxygen evolution reaction (OER) is considered an imperative step in the electrocatalytic water splitting process to obtain clean hydrogen fuel. The scarcity of noble metals impedes the practice of such technology at a commercial scale. To replace noble metal electrocatalysts with non-expensive and abundant materials is critical for the practical application of this technology. Herein, we report a novel approach to fabricate 1D nitrogen-doped carbon coated ternary NiCo2O4 nanorods (NiCo2O4@NC) derived from metal–organic frameworks (MOFs), which display a low overpotential (η ≈ 296 mV @10 mA cm−2), a small Tafel slope (53 mV dec−1) and excellent durability for OER in an alkaline medium, which is higher than for a commercially available Ir/C electrocatalyst (η ≈ 350 mV @10 mA cm−2). Such higher electrochemical properties can be primarily attributed to the high electrochemical surface area, the synergistic effect from chemical compositions and the unique mesoporous architecture with a support of nitrogen-doped carbon species. The proposed strategy for the controlled design and fine-tuning of MOF derived functional materials provides projections for producing remarkably active and stable electrocatalysts in electrochemical energy devices. This work presents a meaningful approach to understanding the effect of morphological engineering on electrocatalytic OER activity.

SiO based materials have attracted attention as promising anodes for lithium-ion batteries (LIBs) with high energy density. However, severe volume variation and poor conductivity limit the development of SiO based materials. In this study, carbon coated SiO nanoparticles embedded in N-doped carbon nanosheets (SiO@C/CNSs) have been fabricated through simple ball milling followed by annealing treatment, which is facile and scalable. The g-C3N4 precursor plays a multifunctional role as a sacrificial template, nitrogen source for doping, and minor carbon source. The presence of N-doped porous carbon nanosheets could minimize the volume expansion, enhance the reaction kinetics and retain the integrity of the electrode. The SiO@C/CNS anode exhibits a stable reversible capacity of 690 mA h g−1 up to 400 cycles at 1 A g−1 and excellent rate capability. The SiO@C/CNS//LiFePO4 full cell further confirms its potential as a promising anode for high capacity LIBs.

Herein, nickel@nitrogen-doped carbon nanotubes (Ni@NCNTs) are prepared by a simple and reliable method with Ni-based complex as single-source precursor. Significantly, the formation of CNTs is not susceptible to the calcination temperature and ramping rate and Ni@NCNTs can be attained from 430 to 900 °C in an inert atmosphere. Then they are the first time to be applied as the anode material for sodium–ion batteries. The presence of Ni nanoparticles (NPs) facilitates the solid electrolyte interface film over the anode surface and improves the capacity retention of the host material, especially at the high rates. Furthermore, Na+ diffusion is reinforced after the introduction of Ni NPs. Ni@NCNTs obtained at 500 °C (Ni@NCNTs-500) exhibit the best capacity retention and rate capability. Kinetics analyses demonstrate the faster electron transportation and ion diffusion than others prepared at other temperatures. The surficial capacitance storage favors the fast electrochemistry kinetics. It delivers a high specific capacity (192 mA h g−1 at 0.5 A g−1), excellent cycling stability (103 mA h g−1 after 10,000 cycles at 10 A g−1), and outstanding high-rate capability up to 20 A g−1 (118 mA h g −1). The related full cells confirm a high energy density of 140 Wh kg−1 at 38.16 W kg−1 and 44.27 W h kg−1 at 762 W kg−1.

Organic electrode materials have shown potential for rechargeable batteries because they are environmentally friendly, earth-abundant sources, recyclable, high sustainable, designable, flexible, and lightweight. However, low electrical conductivity and dissolution in organic liquid electrolytes hinder their further development. Herein, MXene/organics heterostructures are designed to address the problems of organic electrodes via a scalable and simple electrostatic self-assembly strategy. Under the effect of the electrostatic interaction, organic cathode material, 3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA), is tightly attached to MXene nanosheets. Owing to the high electronic conductivity and special two-dimensional (2D) structure of MXene nanosheets, the issues of PTCDA cathode are effectively relieved. When applied in lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs), the MXene@PTCDA heterostructure exhibits significantly enhanced rate capability and cycling performance than bare PTCDA. The heterostructures proposed here can be applied to other (K, Zn, Al, Mg, Ca, etc.) battery systems. In addition to energy storage and conversion, the heterostructures can be also extended to many fields such as catalysis, sensors, electronics, optics, membranes, semiconductors, biomedicines, etc.

Amorphous MoS

In spite of the valuable advancements in the fabrication of transition-metal selenides (TMSs)-based hybrid structures, only single-metal selenides have been obtained through most of the present methods. Herein, a facile room-temperature self-polymerization and subsequent selenization strategy is proposed for the synthesis of bimetallic Mox W1-x Se2 nanosheets with expanded interlayers decorated with N-doped carbon-matrix assembled flowerlike hierarchical microspheres (Mox W1-x Se2 /NC). Depending on the excellent coordination ability of dopamine with metal ions, self-formed flowerlike single precursors are harvested. The unique hybrid architecture benefits the penetration of the electrolyte, accelerates Na+ insertion/extraction kinetics, enhances electron-transfer ability, and alleviates the volume expansion and aggregation during cycling processes. Therefore, the bimetallic Mox W1-x Se2 /NC electrode delivers high reversible capacities of 264 mA h g-1 at 1 A g-1 for 700 cycles, 204.4 mA h g-1 at 4 A g-1 for 1400 cycles, and 153.3 mA h g-1 at 8 A g-1 for 2000 cycles, as well as an excellent rate capability up to 10 A g-1 with a capacity of 188.9 mA h g-1 . Our study offers an effective strategy to boost sodium storage performance through elaborate structural engineering.

Lithium-sulfur batteries have been attracting considerable research attention due to their high energy densities and low costs. However, one of their main challenges is the undesired shuttling of polysulfides, causing rapid capacity degradation. Herein, we report the first example of sulfiphilic VSe2 ultrafine nanocrystals immobilized on nitrogen-doped graphene to modify the battery separator for alleviating the shuttling problem. VSe2 nanocrystals provide numerous active sites for chemisorption of polysulfides as well as benefit the nucleation and growth of Li2S. Furthermore, the kinetic reactions are accelerated which is confirmed by higher exchange current density and higher lithium ion diffusion coefficient. And the first-principles calculations further show that the exposed sulfiphilic planes of VSe2 boost the redox of Li2S. When used as separators within the lithium sulfur batteries, the cell indicates greatly enhanced electrochemical performances with excellent long cycling stability and exceptional rate capability up to 8 C. Moreover, it delivers a higher areal capacity of 4.04 mAh·cm−2 as well as superior cycling stability with sulfur areal loading up to 6.1 mg·cm−2. The present strategy can encourage us in engineering novel multifunctional separators for energy-storage devices.

Rechargeable aqueous zinc-ion batteries have become an emerging candidate for large-scale energy storage due to their low cost and high safety, the lack of suitable advanced cathode materials with ...

High-performance cathodes are essential for all kinds of rechargeable batteries, and vanadium pentoxide (V2O5) has wide applications as a cathode in various batteries because of its high theoretica...

Vanadium-based compounds with an open framework structure have become the subject of much recent investigation into aqueous zinc-ion batteries (AZIBs) due to high specific capacity. However, there are some issues with vanadium dissolution from a cathode framework as well as the generation of byproducts during discharge that should not be ignored, which could cause severe capacity deterioration and inadequate cycle life. Herein, we report several barium vanadate nanobelt cathodes constructed of two sorts of architectures, i.e., Ba1.2V6O16·3H2O and BaV6O16·3H2O (V3O8-type) and BaxV2O5·nH2O (V2O5-type), which are controllably synthesized by tuning the amount of barium precursor. Benefiting from the robust architecture, layered BaxV3O8-type nanobelts (Ba1.2V6O16·3H2O) exhibit superior rate capability and long-term cyclability owing to fast zinc-ion kinetics, enabled by efficiently suppressing cathode dissolution as well as greatly eliminating the generation of byproduct Zn4SO4(OH)6·xH2O, which provides a reasonable strategy to engineer cathode materials with robust architectures to improve the electrochemical performance of AZIBs.

Z-scheme photocatalytic systems, consisting of semiconductor/semiconductor heterostructures, mimic the natural photosynthesis and enhance the photocatalytic activity dramatically. Herein, we have for the first time synthesized unique all-solid-state Z-scheme ternary heterostructures by growing CdS nano-hemispheres radially assembled with nanorods as the core and CoS hexagonal nanoflakes as the shell on graphene sheets (CdS/Co9S8-RGO) through a facile one-pot hydrothermal method and subsequent annealing treatment. Furthermore, the growth mechanism is explored and analyzed by monitoring the intermediates in terms of structure and composition. The heterostructures form three paths available for charge carrier transfer and separation, wherein a redox-mediator-free Z-scheme constitutes CdS and Co9S8 and upgrades to an all-solid-state Z-scheme system by combination with RGO. Moreover, due to the excellent photon capture capability and electric conductivity, RGO also made great contribution to the effective separation and transfer of photogenerated carriers. Benefiting from efficient charge transfer and separation, CdS/Co9S8-RGO exhibits a H2 evolution rate up to 4.82 mmol h−1 g−1 and remarkable activity stability even after 20 h of photocatalytic reaction. We believe that the design philosophy via the plain synthesis merges multiple structural interfaces and transfer paths in a system reported here, shedding an insight into the design of other photocatalysts.

Lithium–sulfur batteries (LSBs) have been regarded as potential energy storage devices by virtue of their high theoretical capacity, natural abundance of materials and low cost. However, the notorious shuttle effect and sluggish reaction kinetics are still significant challenges for further development. Herein, Ni12P5 nanoparticles are devised and grown on a reduced graphene oxide (Ni12P5@rGO) framework via a self-template and recrystallization–self-assembly strategy, as the modifier for separators in LSBs for the first time. The support of rGO for Ni12P5 nanoparticles could solve the self-aggregation problem. Ni12P5 nanoparticles not only effectively adsorb polysulfides by polar interaction, but also supply active sites to ameliorate the kinetics of the redox reaction of sulfur. Consequently, when a sulfur-containing commercial acetylene black material (70 wt% sulfur content) is used as the cathode composite without complicated fabrication or surface modification, an LSB with Ni12P5@rGO modified separator shows excellent cycling stability and a capacity degradation of 0.074% per cycle at the current density of 1 C for 500 cycles. When the areal mass of sulfur further increases to 3.5 mg cm−2, the capacity degradation is only 0.071% per cycle at 150 cycles. This study could accelerate the application of phosphides in LSBs.

Lithium–sulfur (Li–S) batteries have attracted much attention due to their ultrahigh theoretical specific capacity. However, serious capacity attenuation caused by shuttle effect still inhibits the performance improvement. Herein, a modified separator consists of the few-layer graphene as a highly conductive network and stable scaffold to support P-doped boron nitride (denoted as BN-P@GO) as the functional interlayer of Li–S batteries. The cell with the interlayer provides an initial discharge capacity as high as 1045.3 mAh g−1, and retains a high reversible capacity of 728.7 mAh g−1 at 1 C after 500 cycles with a capacity decay of 0.061% per cycle. Moreover, the rate capability is also superior to cells with BN@GO or BN-P interlayers, i.e. reversible capcity of 457.9 mAh g−1 even at 3 C. The excellent electrochemical performance is ascribed to the synergistic effect of physical barrier and chemical adsorption for dissolved polysulfides provided by the modified layer. Furhtermore, it also mitigates the polarization and promotes kinetic reactions of the cells. This work provides a concise and effective method for commercialization of lithium–sulfur batteries.