Ultrathin cobalt nickel selenides (Co0.5Ni0.5Se2) nanosheet arrays anchoring on Ti3C2 MXene for high-performance Na+/K+ batteries

Facile synthesis of NiCoSe2@carbon anode for high-performance sodium-ion batteries

Sodium-ion batteries offer significant advantages in terms of low-temperature performance and safety. In this study, we present a straightforward synthetic approach to produce bimetallic selenide NiCoSe2 nanoparticles grown on a three-dimensional porous carbon framework for application as anode materials in sodium-ion batteries. This unique architecture enhances reaction kinetics and structural stability. The three-dimensional interconnected porous carbon network establishes a continuous pathway of electronic conductive, while increasing specific surface area and mitigating volume expansion. Consequently, these features expedite ion transfer and enhance electrolyte interaction. Notably, compared to CoSe, NiCoSe2 exhibits reduced ion transport distances and lower sodium diffusion barriers. Leveraging these attributes, NiCoSe2/N, Se co-doped carbon composite materials (NiCoSe2/NSC) demonstrate a high specific capacity of 320.8 mAh/g, even after 1000 cycles at 5.0 A/g, with a capacity retention rate of 85.1%. The study further delves into the revelation of the reaction mechanism and ion transport pathway through in-situ X-ray diffraction (XRD) analysis and theoretical calculations. The development of these anode materials is poised to pave the way for advancements in sodium-ion battery technology.

Architectural design of anode materials for superior alkali-ion (Li/Na/K) batteries storage

Developing high-performance anode materials remains a significant challenge for clean energy storage systems. Herein, we investigated the (MXene/MoSe2@C) heterostructure hybrid nanostructure as a superior anode material for application in lithium, sodium, and potassium ion batteries (LIBs, SIBs, and PIBs). Moreover, the anode structure's stability was examined via the open-source Large-scale atomic/molecular massively Parallel Simulator code. Our results indicated that the migration of SIBs toward the anode material is significantly greater than other ions during charge and discharge cycles. Therefore, SIBs systems can be competitive with PIBs and LIBs systems. In addition, the average values of the potential energies for the anode materials/ions complexes are about ~ - 713.65, ~  - 2030.41, and ~ - 912.36 kcal mol-1 in systems LIBs, SIBs, and PIBs, respectively. This study provides a rational design strategy to develop high-performance anode materials in SIBs/PIBs/LIBs systems, which can be developed for other transition metal chalcogenide-based composites as a superior anode of alkali metal ion battery storage systems.

Construction of 2D sandwich-like Na2V6O16·3H2O@MXene heterostructure for advanced aqueous zinc ion batteries

Aqueous zinc ion batteries (AZIBs) have attained enormous attention in the last few years. The cathode materials of aqueous zinc ion batteries play a vital effect in their electrochemical and battery properties. In this manuscript, Sandwich-like MXene@Na2V6O16·3H2O (NVO@MXene) heterostructure was successfully prepared by the combination and cooperation of the layer lattice structure of Na2V6O16·3H2O and the high conductivity of MXene. When used as the cathode material for AZIBs, NVO@MXene demonstrates preeminent rate capability and excellent reversible capacity of 175 mAh/g after 3000 cycles at 5 A/g with a retention rate of 88.9 % of initial discharge capacity. The outstanding battery performance can be attributed to the MXene layers with high conductivity for accelerating the ion diffusion rate and reducing the agglomeration of Na2V6O16·3H2O nanowires during the (dis)charge process. Meanwhile, the stable layered structure of Na16V6O6·3H2O with wide interlamellar spacing (d = 7.9 Å) is also favorable for the s fast intercalation/deintercalation of Zn2+. Finally, ex-situ X-ray diffraction and X-ray photoelectron spectroscopy were applied to study and reveal the energy storage mechanism of this novel material for aqueous zinc ion batteries.

Synergetic Sn Incorporation-Zn Substitution in Copper-Based Sulfides Enabling Superior Na-Ion Storage

Transition-metal sulfides have been regarded as perspective anode candidates for high-energy Na-ion batteries. Their application, however, is precluded severely by either low charge storage or huge volumetric change along with sluggish reaction kinetics. Herein, an effective synergetic Sn incorporation-Zn substitution strategy is proposed based on copper-based sulfides. First, Na-ion storage capability of copper sulfide is significantly improved via incorporating an alloy-based Sn element. However, this process is accompanied by sacrifice of structural stability due to the high Na-ion uptake. Subsequently, to maintain the high Na-ion storage capacity, and concurrently improve cycling and rate capabilities, a Zn substitution strategy (taking partial Sn sites) is carried out, which could significantly promote Na-ion diffusion/reaction kinetics and relieve mechanical strain-stress within the crystal framework. The synergetic Sn incorporation and Zn substitution endow copper-based sulfides with high specific capacity (≈560 mAh g-1 at 0.5 A g-1 ), ultrastable cyclability (80 k cycles with ≈100% capacity retention), superior rate capability up to 200 A g-1 , and ultrafast charging feature (≈4 s per charging with ≈190 mAh g-1 input). This work provides in-depth insights for developing superior anode materials via synergetic multi-cation incorporation/substitution, aiming at solving their intrinsic issues of either low specific capacity or poor cyclability.

Recent advances and promise of MXene-based composites as electrode materials for sodium-ion and potassium-ion batteries

With the increasing demand for sustainable energy and concerns about the scarcity of lithium resources, sodium and potassium ion batteries have emerged as promising alternative energy storage technologies. MXene, as a novel two-dimensional material, possesses exceptional electrical conductivity, high surface area, and tunable structural features that make it an ideal candidate for high-performance electrode materials. However, its limited theoretical capacity hinders its widespread application. To overcome this limitation, MXene has been combined with other materials through synergistic effects between different components to enhance the overall electrochemical performance and expand its application in sodium/potassium ion batteries. Recently, substantial advancements have been realized in the exploration of MXene-based composites as energy storage materials, encompassing their synthesis, design, and the comprehension of charge storage mechanisms. This paper aims to propose a comprehensive summary of the latest developments in MXene-based composites as electrode materials for sodium ion batteries and potassium ion batteries, with a particular emphasis on the enhanced physicochemical properties resulting from composite formation. Moreover, the challenges faced by MXene materials in sodium ion batteries and potassium ion batteries are thoroughly discussed, and future research directions to further advance this field are proposed.

Interface ion-exchange strategy of MXene@FeIn2S4 hetero-structure for super sodium ion half/full batteries

Herein, a well-designed hierarchical architecture of bimetallic transition sulfide FeIn2S4 nanoparticles anchoring on the Ti3C2 MXene flakes has been prepared by cation exchange and subsequent high-temperature sulfidation processes. The introduction of MXene substrate with excellent conductivity not only accelerates the migration rate of Na+ to achieve fast reaction dynamics but provides abundant deposition sites for the FeIn2S4 nanoparticles. In addition, this hierarchical structure of MXene@FeIn2S4 can effectively restrain the accumulation of MXene to guarantee the maximized exposure of redox active sites into the electrolyte, and simultaneously relieve the volume expansion in the repeated discharging/charging processes. The MXene@FeIn2S4 displays outstanding rate capability (448.2 mAh g-1 at 5 A g-1) and stable long cycling performance (428.1 mAh g-1 at 2 A g-1 after 200 cycles). Moreover, the Nay-In6S7 phase detected by ex-situ XRD and XPS characterization may be regarded as a "buffer" to maintain the stability of the Fe-based components and enhance the reversibility of the electrochemical reaction. This work confirms the practicability of constructing the hierarchical structure bimetallic sulfides with the promising electrochemical performance.

Hetero-structural and hetero-interfacial engineering of MXene@Bi2S3/Mo7S8 hybrid for advanced sodium/potassium-ion batteries

Herein, heterogeneous bimetallic sulfides Bi2S3/Mo7S8 nanoparticles anchored on MXene (Ti3C2Tx) nanosheets (MXene@Bi2S3/Mo7S8) were prepared through a solvothermal process and subsequent chemical vapor deposition process. Benefiting from the heterogeneous structure between Bi2S3 and Mo7S8 and the high conductivity of the Ti3C2Tx nanosheets, the Na+ diffusion barrier and charge transfer resistance of this electrode are effectively decreased. Simultaneously, the hierarchical architectures of Bi2S3/Mo7S8 and Ti3C2Tx not only effectively inhibit the re-stacking of MXene and the agglomeration of bimetallic sulfides nanoparticles, but also dramatically relieve the volume expansion during the periodic charge/discharge processes. As a result, the MXene@Bi2S3/Mo7S8 heterostructure demonstrated remarkable rate capability (474.9 mAh/g at 5.0 A/g) and outstanding cycling stability (427.3 mAh/g after 1400 cycles at 1.0 A/g) for sodium ion battery. The Na+ storage mechanism and the multiple-step phase transition in the heterostructures are further clarified by the ex-situ XRD and XPS characterizations. This study paves a new way to design and exploit conversion/alloying type anodes of sodium ion batteries with hierarchical heterogeneous architecture and high-performance electrochemical properties.

Topochemical and phase transformation induced Co9S8/NC nanosheets for high-performance sodium-ion batteries

In this paper, a cobalt-based sulfide nanosheet structure (Co9S8/NC) was successfully synthesized by topochemical and phase transformation processes from a dodecahedral cobalt-based imidazole skeleton (ZIF-67) as a self-template. The 2D sheet structure facilitates full contact of electrode materials with the electrolyte and shortens the diffusion distance for electrons and ions. In addition, the nitrogen-doped carbon framework derived from ZIF-67 promotes electron transfer and provides a reliable skeleton to buffer volume expansion during discharging and charging. Finally, Co9S8/NC exhibits excellent rate capability and stable cycling performance for the anode of a sodium ion battery, delivering a specific capacity remaining at 530 mA h g-1 after 130 cycles at a current density of 1 A g-1.

Synergistically enhanced sodium ion storage from encapsulating highly dispersed cobalt nanodots into N, P, S tri-doped hexapod carbon framework

Development of multitudinous heteroatoms co-doped carbon nanomaterials with pleasurable electrochemical behavior for sodium ion batteries is still an enormous challenge. Herein, high dispersion cobalt nanodots encapsulating into N, P, S tri-doped hexapod carbon (H-Co@NPSC) have been victoriously synthesized via H-ZIF67@polymer template strategy with using poly (hexachlorocyclophos-phazene and 4,4'-sulfonyldiphenol) as both carbon source and N, P, S multiple heteroatom doping sources. The uniform distribution of cobalt nanodots and the Co-N bonds are conducive to form a high conductive network, which synergistically increase a lot adsorption sites and lessens the diffusion energy barrier, thereby improving the fast Na⁺ ions diffusion kinetics. Consequently, H-Co@NPSC delivers the reversible capacity of 311.1 mAh g^-1 at 1 A g^-1 after 450 cycles with 70% capacity storage rate, while obtains the capacity of 237.1 mAh g^{- 1} after 200 cycles at the elevated current densities of 5 A g^-1 as an excellent anode material for SIBs. These interesting results pave a generous avenue for the exploitation of promising carbon anode materials for Na⁺ storage.

Multilayer structure covalent organic frameworks (COFs) linking by double functional groups for advanced K+ batteries

Covalent organic frameworks (COFs) are regarded as the potential and promising anode materials for potassium ion batteries (PIBs) on account of their robust and porous crystalline structure. In this work, multilayer structural COF connected by double functional groups, including imine and amidogent through a simple solvothermalprocess, have been successfully synthesized. The multilayer structure of COF can provide fast charge transfer and combine the merits of imine (the restraint of irreversible dissolution) and amidogent (the supply of more active sites). It presents superior potassium storage performance, including the high reversible capacity of 229.5 mAh g^-1 at 0.2 A g^-1 and outstanding cycling stability of 106.1 mAh g^-1 at the high current density of 5.0 A g^-1 after 2000 cycles, which is superior to the individual COF. The structural advantages of the covalent organic framework linking by double functional groups (d-COF) can develop a new road for that COF anode material for PIBs in further research.

Recent Advances in Porous Carbon Materials as Electrodes for Supercapacitors

Porous carbon materials have demonstrated exceptional performance in various energy and environment-related applications. Recently, research on supercapacitors has been steadily increasing, and porous carbon materials have emerged as the most significant electrode material for supercapacitors. Nonetheless, the high cost and potential for environmental pollution associated with the preparation process of porous carbon materials remain significant issues. This paper presents an overview of common methods for preparing porous carbon materials, including the carbon-activation method, hard-templating method, soft-templating method, sacrificial-templating method, and self-templating method. Additionally, we also review several emerging methods for the preparation of porous carbon materials, such as copolymer pyrolysis, carbohydrate self-activation, and laser scribing. We then categorise porous carbons based on their pore sizes and the presence or absence of heteroatom doping. Finally, we provide an overview of recent applications of porous carbon materials as electrodes for supercapacitors.

Heterostructure and doping dual strategies engineering of MoS1.5Se0.5@VS2 nanosheets aggregated nano-roses for super sodium-ion batteries

Herein, selenium (Se)-doped MoS_1.5Se_0.5@VS₂ nanosheets aggregated nano-roses were successfully prepared from a simple hydrothermal process and the subsequent selenium doping process. The hetero-interfaces between MoS_1.5Se_0.5 and VS₂ phase can effectively promote the charge transfer. Meanwhile, the different redox potentials of MoS_1.5Se_0.5 and VS₂ alleviate volume expansion during the repeated sodiation/desodiation processes, which improves the electrochemical reaction kinetics and structural stability of electrode material. Besides, Se doping can induce charge reconstruction and improve the conductivity of electrode materials, resulting in improved diffusion reaction kinetics by expanding interlayer spacing and exposing more active sites. When used as anode material for sodium ion batteries (SIBs), the MoS_1.5Se_0.5@VS₂ heterostructure exhibits excellent rate capability and long-term cycling stability with the capacity of 533.9 mAh g^-1 at 0.5 A g^-1 and a reversible capacity of 424.5 mAh g^-1 after 1000 cycles at 5 A g^-1, demonstrating potential application as anode material for SIBs.

Selenide-doped bismuth sulfides (Bi2S3-xSex) and their hierarchical heterostructure with ReS2for sodium/potassium-ion batteries

In this work, selenide-doped bismuth sulfides (Bi₂S_3-xSe_x) was successfully prepared through Se doping Bi₂S₃ Se to improve the electronic conductivity and increase the interlayer spacing. Then the anisotropic ReS₂ nanosheet arrays were grown on the surface of Bi₂S_3-xSe_x to form a hierarchical heterostructure (Bi₂S_3-xSe_x@ReS₂). The doping and construction of heterostructure processes can greatly improve the electrochemical conductivity of electrode materials and relieve the volume expansion during the continuous charge/discharge processes. While applied as SIBs anode, the specific capacity of 330 mAh g^-1 was maintained after 450 cycles at the current density of 1.0 A g^-1. It can also keep 200 mAh g^-1 specific capacity after 900 cycles at 1.0 A g^-1 for the anode of PIBs. This heterogeneous engineering and doping dual strategies could provide a good idea for the synthesis of new bimetallic sulfides with outstanding battery performance for SIBs and PIBs.

Metal-organic framework derived bimetallic selenide embedded in nitrogen-doped carbon hierarchical nanosphere for highly reversible sodium-ion storage

Bimetallic selenides with various valence transitions and high theoretical capacities are extensively studied as anodes for sodium-ion-batteries (SIBs), but their huge volume changes and poor capacity retention limit their practicality. Herein, a facile and controllable strategy using a binary Ni-Co metal-organic framework (MOF) precursors followed by the selenization process, which produced a cobalt nickel selenide/N-doped carbon composite ((CoNi)Se₂/NC) that maintained the hierarchical nanospheres structure. Such a distinctive structure affords both Na⁺ and electron diffusion pathways in the electrochemical reactions as well as high electrical conductivity, thus leading to superior electrochemical performance when the designed composite is utilized as an anode in SIBs. The resulting nanospheres-like (CoNi)Se₂/NC hierarchical structure exhibits a high specific capacity of 526.8 mA h g^-1 at 0.2 A/g over 100 cycles, a stable cycle life with no obvious capacities loss at 1.0 and 3.0 A/g after 500 cycles, and exceptional rate capability of 322.9 mA h g^-1 at 10.0 A/g.

MOF derived cobalt-nickel bimetallic phosphide (CoNiP) modified separator to enhance the polysulfide adsorption-catalysis for superior lithium-sulfur batteries

Lithium-sulfur batteries (LSBs) have aroused great research interest due to their high theoretical capacity and high energy density. To further develop lithium-sulfur batteries, it has become more and more important to put more efforts in promoting the adsorption and rapid catalytic conversion of lithium polysulfides (LiPSs). Herein, Ni/Co bimetallic phosphides were encapsulated into nitrogen-doped dual carbon conductive network (NiCoP@NC) by annealing and phosphorizing Ni-ZIF-67 precursor at high temperature. Due to their numerous co-adsorption/catalytic sites and high conductivity of carbon skeleton, the encapsulated Ni/Co phosphides particles could significantly enhance the anchoring and catalytic conversion of LiPSs and provide ultrafast channels for Li⁺ transport. When used as a modified separator for LSBs, the cells displayed superior performance with an initial capacity of 1083.4 m Ah g^-1 at 0.5 C and outstanding cycle stability with a capacity decay rate of only 0.09% per cycle for 300 cycles. Besides, even at high sulfur loading (3.2 mg cm^-2), they still present satisfactory performance. Therefore, this study presents a novel strategy on how to use MOF derived bimetallic phosphides with chemical adsorption and catalytic conversion of polysulfides for high-power advanced lithium-sulfur batteries.

Cobalt-nickel bimetallic sulfide (NiS2/CoS2) based dual-carbon framework for super sodium ion storage

Design hybrid metal sulfides-based anode materials is one of the most effective approaches to improve the performance of sodium-ion batteries (SIBs). However, owing to the huge volume expansion, the capacity of sulfide-based anode will decay significantly after repeated charge/discharge processes. Herein, we reported the successful demonstration of anode material based on concaved NiS₂@CoS₂ nanocube (NCSC) via a chemical etching strategy, which was derived from etching and sulfidation of Ni-Co coordination polymers (NiCoCP) precursor. The obtained NCSC anode materials deliver a high specific sodium storage capacity of 848 mAh g^-1 at 0.1 A g^-1 and a stable cyclability of 572 mAh g^-1 at 5 A g^-1 after 830 cycles. This special etching strategy exploit a novel way for the design and preparation of high-performance anode materials for SIBs.

Defect engineering of molybdenum disulfide nanosheets boosting super Zn2+ storage from polyaniline intercalation

In this work, peony-like structured MoS₂ with intercalation of polyaniline and crystal defects was prepared by a simple hydrothermal method. The defect-rich structure and broad interlayer distance can effectively provide vast ion transport paths to enhance the ion diffusion rate. PA-MoS₂ can maintain 157.7 mA h g^-1 at 0.1 A g^-1 after 80 cycles and 77.8 mA h g^-1 at 1 A g^-1 after 750 cycles.

Zeolite Imidazolate Frameworks (ZIFs) Derived Nanomaterials and their Hybrids for Advanced Secondary Batteries and Electrocatalysis

Zeolite imidazolate frameworks (ZIFs), as a typical class of metal-organic frameworks (MOFs), have attracted a great deal of attention in the field of energy storage and conversation due to their chemical structure stability, facile synthesis and environmental friendliness. Among of ZIFs family, the zinc-based imidazolate framework (ZIF-8) and cobalt-based imidazolate framework (ZIF-67) have considered as promising ZIFs materials, which attributed to their tunable porosity, stable structure, and desirable electrical conductivity. To date, various ZIF-8 and ZIF67 derived materials, including carbon materials, metal oxides, sulfides, selenides, carbides and phosphides, have been successfully synthesized using ZIFs as templates and evaluated as promising electrode materials for secondary batteries and electrocatalysis. This review provides an effective guide for the comprehension of the performance optimization and application prospects of ZIFs derivatives, specifically focusing on the optimization of structure and their application in secondary batteries and electrocatalysis. In detail, we present recent advances in the improvement of electrochemical performance of ZIF-8, ZIF-67 and ZIF-8@ZIF-67 derived nanomaterials and their hybrids, including carbon materials, metal oxides, carbides, oxides, sulfides, selenides, and phosphides for high-performance secondary batteries and electrocatalysis.