Sodium-ion batteries (SIBs) are an attractive battery system because of similar characteristics to lithium-ion batteries (LIBs) and large Na element abundance. Nevertheless, exploring stable, high-capacity and high-rate anode materials for SIBs is still challenging now. Herein, diethylenetriamine (DETA) molecular template derived ultrathin N-doped carbon (NC) layer decorated CoSe₂ nanobelts (CoSe₂/NC) are prepared by solvothermal reaction followed by calcination process. The CoSe₂/NC exhibits large potential as an anode for SIBs. Experiments and theoretical calculations reveal that the in situ formed conductive ultrathin NC layer can not only relieve the volume change of CoSe₂ but also accelerate electron and ion transport. In addition, the nanobelt structure of CoSe₂/NC with abundant exposed active sites can obviously accelerate the electrochemical kinetics. Under the synergistic effect of special nanobelt structure and NC layer, the rate as well as cycling performances of CoSe₂/NC are obviously improved. A superior capacity retention of 94.8% is achieved at 2 A·g⁻¹ after 2000 cycles. When using Na₃V₂(PO₄)₃ cathodes, the pouch full batteries can work steadily at 0.5 C, verifying the application ability. CoSe₂/NC anodes also exhibit impressive performances in LIBs and potassium-ion batteries (PIBs).

The application of light-weight current collectors is preferred because of the increased energy density of the batteries. Bearing it in mind, the cathode is designed with self-made paperlike memberane as current collector coupled with another interlayer to enable the high-energy-density lithium-sulfur batteries. Via a facile and green step-by-step methodology, the hybrid membrane is finalized successfully, consisting of reduced graphene oxide sheets covering paper-derived carbon (GPC) bearing Fe@Fe₂O₃ and Fe_1−xS@Fe₂O₃ core–shell nanoparticles (FeFeO/FeSFeO@GPC). The film works as the current collector and interlayer simultaneously considering the porous and conductive features. As demonstrated by the electrochemical testing, the FeFeO/FeSFeO@GPC hybrid cell exhibits attractive cycling stability and superior rate capability. The cell configuration and structural/composition merits of FeFeO/FeSFeO@GPC film facilitate the faster reaction kinetics, conducive to the improvement of capacity retention. In view of the effective cathode design, the areal sulfur loading is increased to 10.46 mg·cm⁻² and a reversible capacity of 6.67 mAh·cm⁻² can be retained after 60 cycles at 0.1 C.

Engineering the structure and composition of electrode materials is one of the essential means for achieving excellent electrochemical performance. The rational design of Na⁺ host materials is still a massive challenge for sodium ion batteries (SIBs). Herein, MoSe₂/TiO₂ heterostructure is integrated with N-doped carbon nanosheets to assemble into hierarchical flower-like porous core–shell microspheres (MoSe₂/TiO₂@N-C), which is firstly reported by room-temperature stirring coupled with vulcanization treatment. The cavity of the core–shell structure could provide enough storage space for Na⁺ and alleviate the volume expansion during charge/discharge processes. The apertures between nanosheets provide a guarantee for the rapid penetration of electrolyte to enhance the utilization rate of electrode materials. Furthermore, building heterostructures by combining different phase structures can facilitate electron transfer and accelerate reaction kinetics. Benefiting from the synergistic contributions of structure and composition, MoSe₂/TiO₂@N-C as SIBs anode material shows better reversible capacities of 302.5 mAh·g⁻¹ at 1 A·g⁻¹ for 400 cycles and 217.4 mAh·g⁻¹ at 4 A·g⁻¹ for 900 cycles. Strikingly, the reversible capacities can be restored entirely to the initial level after a high current density cycle.

Cost-effectively, eco-friendly rechargeable aqueous zinc-ion batteries (AZIBs) have reserved widespread concerns and become outstanding candidate in energy storage systems. However, the progress pace of AZIBs suffers from limitation of suitable and affordable cathode materials. Herein, a double-effect strategy is realized in a one-step hydrothermal treatment to prepare V₂O₅ nanoribbons with intercalation of Ce and introduction of abundant oxygen defects (O_d-Ce@V₂O₅) to enhance electrochemical performance synergistically. Coupled with the theoretical calculation results, the introduction of Ce ions intercalation and oxygen vacancies in V₂O₅ structure enhances the electrical conductivity, reduces the adsorption energy of zinc ions, enlarges the interlayer distance, renders the structure more stable, and facilitates rapid diffusion kinetics. As expected, the desirable cathode delivers the reversible capacity of 444 mAh·g⁻¹ at 0.5 A·g⁻¹ and shows excellent Coulombic efficiency, as well as an extraordinary energy density of 304.9 Wh·kg⁻¹. The strategy proposed here may aid in the further development of cathode materials with stable performance for AZIBs.

Lithium-sulfur (Li-S) batteries have been widely investigated attributed to their advantages of high energy density and cost effectiveness. However, it is still limited by the uncontrolled shuttle effect of the sulfur cathode and the promiscuous dendrite growth over the lithium anode. To handle the above issues, the highly conductive CoTe catalyst is precisely loaded onto nitrogen-doped nanotube and graphene-like carbon (CoTe $\subset$NCGs), which is employed as a bi-functionally integrated host. On the lithium anode, the CoTe $\subset$NCGs with excellent lithiophilic property effectively regulate the uniform deposition of lithium and achieve the effect of suppressing the disorderly growth of lithium dendrites. On the sulfur cathode, the electrochemical conversion of lithium polysulfides (LiPSs) is catalyzed to mitigate the notorious shuttle effect. In view of the bifunctionality of CoTe $\subset$NCGs, the assembled full cell can be steadily stable even for 800 cycles at a high rate of 2 C, and the capacity decay rate is only 0.05% per cycle. The areal capacity of 6.0 mAh·cm⁻² is well retained after 50 cycles under the conditions of high sulfur loading, poor electrolyte (a low electrolyte-to-sulfur ratio, E/S = 4.2), and low negative to positive capacity ratio (N/P=1.6:1).

Silicon-based materials has attracted attention as a promising candidate for lithium-ion batteries (LIBs) with high energy density. However, severe volume variation, pulverization, and poor conductivity hindered the development of Si based materials. In this study, porous Si microparticles supported by carbon nanotubes (p-Si/CNT) are fabricated through simple molten salt assisted dealloying process at low temperature followed by acid treatment. The ZnCl₂ molten salt not only provides the liquid environment to enhance the reaction, but also participates the dealloying process and works as template for porous structure when removes by acid treatment. Additionally, distribution of defect sites in CNTs also increases after molten salt process. Density function theory (DFT) calculations further prove the defects could improve the adsorption of Li⁺. The participation of CNTs can also contribute to the reaction kinetics and retain the integrity of the electrode. As expected, the p-Si/CNT anode manifests enhanced lithium-storage performance in terms of superior cycling stability and good rate capability. The p-Si/CNT//LiCoO₂ full cell assembly further demonstrates its potential as a prospective anode for high-performance LIBs.

Designing hybrid transition metal compounds with optimized electronic structure and firmly dispersing them on a matrix to avoid aggregation and shedding is of great significance for achieving high electrocatalytic performances. Herein, an adsorption-complexation-calcination strategy based on channel confining effect is explored to obtain CoN-CoO_x hybrid nanoparticles uniformly dispersed in mesoporous carbon. The CoN-CoO_x/C composite exhibits excellent electrocatalytic behavior for oxygen reduction reaction (ORR). The half-wave potential and durability are comparable or superior to those of Pt/C. When applying as cathode catalyst for a primary zinc-air battery, the open-circuit voltage and peak power density reach up to 1.394 V and 109.8 mW·cm⁻², respectively. A high gravimetric energy density of 950.3 Wh·kg_Zn⁻¹ is delivered at 10 mA·cm⁻² with good rate capability and stability. Density functional theory (DFT) calculation demonstrates the favorable ORR intermediate adsorbability and metallic characteristics of CoN grains with oxide hybridization to optimize the electronic structure. This work provides a facile adjustable approach for obtaining highly dispersed nanoparticles with controllable hybrid composition on a substrate, which is important for future design and optimization of high-performance electrocatalysts.

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.

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.

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.