A Solid‐State Fibriform Supercapacitor Boosted by Host–Guest Hybridization between the Carbon Nanotube Scaffold and MXene Nanosheets

Fiber‐shaped supercapacitors with improved specific capacitance and high rate capability are a promising candidate as power supply for smart textiles. However, the synergistic interaction between conductive filaments and active nanomaterials remains a crucial challenge, especially when hydrothermal or electrochemical deposition is used to produce a core (fiber)–shell (active materials) fibrous structure. On the other hand, although 2D pseudocapacitive materials, e.g., Ti₃C₂T _x (MXene), have demonstrated high volumetric capacitance, high electrical conductivity, and hydrophilic characteristics, MXene‐based electrodes normally suffer from poor rate capability owing to the sheet restacking especially when the loading level is high and solid‐state gel is used as electrolyte. Herein, by hosting MXene nanosheets (Ti₃C₂T _x ) in the corridor of a scrolled carbon nanotube (CNT) scaffold, a MXene/CNT fiber with helical structure is successfully fabricated. These features offer open spaces for rapid ion diffusion and guarantee fast electron transport. The solid‐state supercapacitor based on such hybrid fibers with gel electrolyte coating exhibits a volumetric capacitance of 22.7 F cm⁻³ at 0.1 A cm⁻³ with capacitance retention of 84% at current density of 1.0 A cm⁻³ (19.1 F cm⁻³), improved volumetric energy density of 2.55 mWh cm⁻³ at the power density of 45.9 mW cm⁻³, and excellent mechanical robustness.     

Highly Enhanced Pseudocapacitive Performance of Vanadium‐Doped MXenes in Neutral Electrolytes

2D titanium carbide (Ti₃C₂T_x MXene) is recognized as a promising material for pseudocapacitor electrodes in acidic solutions, while the current studies in neutral electrolytes show much poorer performances. By a simple hydrothermal method, vanadium‐doped Ti₃C₂T_x 2D nanosheets are prepared to tune the interaction between MXene and alkali metal adsorbates (Li⁺, Na⁺, and K⁺) in the neutral electrolyte. Maintaining the 2D morphology of MXene, the coexisting V³⁺ and V⁴⁺ are confirmed to form surface V–C and V–O species. At a medium doping level of V:Ti = 0.17:1, the V‐doped MXene exhibits the highest capacitance of 365.9 F g^?1 in 2 m KCl (10 mV s^?1) and excellent stability (5% loss after 5000 cycles), compared to only 115.7 F g^?1 of pristine MXene. Density functional theory calculations reveal the stronger alkali metal ion–O interaction on V‐doped MXene surface than unmodified MXene and a further capacitance boost to 404.9 F g^?1 using Li⁺‐containing neutral electrolyte is reported, which is comparable to the performance under acidic conditions.     

Functional Tailoring of Multi-Dimensional Pure MXene Nanostructures for Significantly Accelerated Electromagnetic Wave Absorption

Transition metal carbide (Ti₃C₂T_x MXene), with a large specific surface area and abundant surface functional groups, is a promising candidate in the family of electromagnetic wave (EMW) absorption. However, the high conductivity of MXene limits its EMW absorption ability, so it remains a challenge to obtain outstanding EMW attenuation ability in pure MXene. Herein, by integrating HF etching, KOH shearing, and high-temperature molten salt strategies, layered MXene (L-MXene), network-like MXene nanoribbons (N-MXene NRs), porous MXene monolayer (P-MXene ML), and porous MXene layer (P-MXene L) are rationally constructed with favorable microstructures and surface states for EMW absorption. HF, KOH, and KCl/LiCl are used to functionalize MXene to tune its microstructure and surface state (F⁻, OH⁻, and Cl⁻ terminals), thereby improving the EMW absorption capacity of MXene-based nanostructures. Impressively, with the unique structure, proper electrical conductivity, large specific surface area, and abundant porous defects, MXene-based nanostructures achieve good impedance matching, dipole polarization, and conduction loss, thus inheriting excellent EMW absorption performance. Consequently, L-MXene, N-MXene NRs, P-MXene ML, and P-MXene L enable a reflection loss (R_L) value of −43.14, −63.01, −60.45, and −56.50 dB with a matching thickness of 0.95, 1.51, 3.83, and 4.65 mm, respectively.     

Additive-Free Aqueous MXene Inks for Thermal Inkjet Printing on Textiles

Direct printing of functional inks onto flexible substrates allows for scalable fabrication of wearable electronics. However, existing ink formulations for inkjet printing require toxic solvents and additives, which make device fabrication more complex, limit substrate compatibility, and hinder device performance. Even water-based carbon or metal nanoparticle inks require supplemental surfactants, binders, and cosolvents to produce jettable colloidal suspensions. Here, a general approach is demonstrated for formulating conductive inkjet printable, additive-free aqueous Ti₃C₂T_x MXene inks for direct printing on various substrates. The rheological properties of the MXene inks are tuned by controlling the Ti₃C₂T_x flake size and concentration. Ti₃C₂T_x-based electrical conduits and microsupercapacitors (MSCs) are printed on textile and paper substrates by optimizing the nozzle geometry for high-resolution inkjet printing. The chemical stability and electrical properties of the printed devices are also studied after storing the devices for six months under ambient conditions. Current collector-free, textile-based MSCs show areal capacitance values up to 294 mF cm⁻² (2 mV s⁻¹) in poly(vinyl alcohol)/sulfuric acid gel electrolyte, surpassing reported printed MXene-based MSCs and inkjet-printed MSCs using other 2D nanomaterials. This work is an important step toward increasing the functional capacity of conductive inks and simplifying the fabrication of wearable textile-based electronics.     

Architecting the High-Entropy Oxides on 2D MXene Nanosheets by Rapid Microwave-Heating Strategy with Robust Photoelectrochemical Oxygen Evolution Performance

High-entropy oxides (HEO) have recently concerned interest as the most promising electrocatalytic materials for oxygen evolution reactions (OER). In this work, a new strategy to the synthesis of HEO nanostructures on Ti₃C₂T_x MXene via rapid microwave heating and subsequent calcination at a low temperature is reported. Furthermore, the influence of HEO loading on Ti₃C₂T_x MXene is investigated toward OER performance with and without visible-light illumination in an alkaline medium. The obtained HEO/Ti₃C₂T_x-0.5 hybrid exhibited an outstanding photoelectrochemical OER ability with a low overpotential of 331 mV at 10 mA cm⁻² and a small Tafel slope of 71 mV dec⁻¹, which exceeded that of a commercial IrO₂ catalyst (340 mV at 10 mA cm⁻²). In particular, the fabricated water electrolyzer with the HEO/Ti₃C₂T_x-0.5 hybrid as anode required a less potential of 1.62 V at 10 mA cm⁻² under visible-light illumination. Owing to the strong synergistic interaction between the HEO and Ti₃C₂T_x MXene, the HEO/Ti₃C₂T_x hybrid has a great electrochemical surface area, many metal active sites, high conductivity, and fast reaction kinetics, resulting in an excellent OER performance. This study offers an efficient strategy for synthesizing HEO-based materials with high OER performance to produce high-value hydrogen fuel.     

Stabilizing the MXenes by Carbon Nanoplating for Developing Hierarchical Nanohybrids with Efficient Lithium Storage and Hydrogen Evolution Capability

The MXenes combining hydrophilic surface, metallic conductivity and rich surface chemistries represent a new family of 2D materials with widespread applications. However, their poor oxygen resistance causes a great loss of electronic properties and surface reactivity, which significantly inhibits the fabrication, the understanding of the chemical nature and full exploitation of the potential of MXene‐based materials. Herein we report a facile carbon nanoplating strategy for efficiently stabilizing the MXenes against structural degradation caused by spontaneous oxidation, which provides a material platform for developing MXene‐based materials with attractive structure and properties. Hierarchical MoS₂/Ti₃C₂‐MXene@C nanohybrids with excellent structural stability, electrical properties and strong interfacial coupling are fabricated by assembling carbon coated few‐layered MoS₂ nanoplates on carbon‐stabilized Ti₃C₂ MXene, exhibiting exceptional performance for Li storage and hydrogen evolution reaction (HER). Remarkably, ultra‐long cycle life of 3000 cycles with high capacities but extremely slow capacity loss of 0.0016% per cycle is achieved for Li storage at a very high rate of 20 A g^?1. They are also highly active HER electrocatalyst with very positive onset potential, low overpotential and long‐term stability in acidic solution. Superb properties highlight the great promise of MXene‐based materials in cornerstone applications of energy storage and conversion.     

Interfacial and Electronic Modulation via Localized Sulfurization for Boosting Lithium Storage Kinetics

Structural modulation endows electrochemical hybrids with promising energy storage properties owing to their adjustable interfacial and/or electronic characteristics. For MXene-based materials, however, the facile but effective strategies for tuning their structural properties at nanoscale are still lacking. Herein, 3D crumpled S-functionalized Ti₃C₂T_x substrate is rationally integrated with Fe₃O₄/FeS heterostructures via coprecipitation and subsequent partial sulfurization to induce a highly active and stable electrode architecture. The unique heterostructures with tuned electronic properties can induce improved kinetics and structural stability. The surface engineering by S terminations on the MXene further unlocks extra (pseudo)capacitive lithium storage. Serving as anode for lithium storage, the optimized electrode delivers an excellent long-term cycling stability (913.9 mAh g⁻¹ after 1000 cycles at 1 A g⁻¹) and superior rate capability (490.4 mAh g⁻¹ at 10 A g⁻¹). Moreover, the (de)lithiation pathways associated with energy storage mechanisms are further revealed by operando X-ray diffraction, in situ electroanalytical techniques, and first-principles calculations. The hybrid electrode is proved to undergo stepwise phase transformations during discharging but a relatively uniform reconversion during charging, suggesting an asymmetric conversion mechanism. This work provides a novel strategy for designing high-performance hybrids and paves the way for in-depth understanding of complex lithium intercalation and conversion reactions.     

Terminal Group-Oriented Self-Assembly to Controllably Synthesize a Layer-by-Layer SnSe2 and MXene Heterostructure for Ultrastable Lithium Storage

Heterostructured materials integrate the advantages of adjustable electronic structure, fast electron/ions transfer kinetics, and robust architectures, which have attracted considerable interest in the fields of rechargeable batteries, photo/electrocatalysis, and supercapacitors. However, the construction of heterostructures still faces some severe problems, such as inferior random packing of components and serious agglomeration. Herein, a terminal group-oriented self-assembly strategy to controllably synthesize a homogeneous layer-by-layer SnSe₂ and MXene heterostructure (LBL-SnSe₂@MXene) is designed. Benefitting from the abundant polar terminal groups on the MXene surface, Sn²⁺ is induced into the interlayer of MXene with large interlayer spacing, which is selenized in situ to obtain LBL-SnSe₂@MXene. In the heterostructure, SnSe₂ layers and MXene layers are uniformly intercalated in each other, superior to other heterostructures formed by random stacking. As an anode for lithium-ion batteries, the LBL-SnSe₂@MXene is revealed to possess strong lithium adsorption ability, the small activation energy for lithium diffusion, and excellent structure stability, thus achieving outstanding electrochemical performance, especially with high specific capacities (1311 and 839 mAh g⁻¹ for initial discharge and charge respectively) and ultralong cycling stability (410 mAh g⁻¹ at 5C even after 16 000 cycles). This work conveys an inspiration for the controllable design and construction of homogeneous layered heterostructures.     

Electrostatically Assembling 2D Nanosheets of MXene and MOF‐Derivatives into 3D Hollow Frameworks for Enhanced Lithium Storage

As an essential member of 2D materials, MXene (e.g., Ti₃C₂T_x) is highly preferred for energy storage owing to a high surface‐to‐volume ratio, shortened ion diffusion pathway, superior electronic conductivity, and neglectable volume change, which are beneficial for electrochemical kinetics. However, the low theoretical capacitance and restacking issues of MXene severely limit its practical application in lithium‐ion batteries (LIBs). Herein, a facile and controllable method is developed to engineer 2D nanosheets of negatively charged MXene and positively charged layered double hydroxides derived from ZIF‐67 polyhedrons into 3D hollow frameworks via electrostatic self‐assembling. After thermal annealing, transition metal oxides (TMOs)@MXene (CoO/Co₂Mo₃O₈@MXene) hollow frameworks are obtained and used as anode materials for LIBs. CoO/Co₂Mo₃O₈ nanosheets prevent MXene from aggregation and contribute remarkable lithium storage capacity, while MXene nanosheets provide a 3D conductive network and mechanical robustness to facilitate rapid charge transfer at the interface, and accommodate the volume expansion of the internal CoO/Co₂Mo₃O₈. Such hollow frameworks present a high reversible capacity of 947.4 mAh g^?1 at 0.1 A g^?1, an impressive rate behavior with 435.8 mAh g^?1 retained at 5 A g^?1, and good stability over 1200 cycles (545 mAh g^?1 at 2 A g^?1).     

Multicomponent Hybridization Transition Metal Oxide Electrode Enriched with Oxygen Vacancy for Ultralong-Life Supercapacitor

Transition metal oxide electrode materials for supercapacitors suffer from poor electrical conductivity and stability, which are the research focus of the energy storage field. Herein, multicomponent hybridization Ni-Cu oxide (NCO-Ar/H₂-10) electrode enriched with oxygen vacancy and high electrical conductivity including the Cu_0.2Ni_0.8O, Cu₂O and CuO is prepared by introducing Cu element into Ni metal oxide with hydrothermal, annealing, and plasma treatment. The NCO-Ar/H₂-10 electrode exhibits high specific capacity (1524 F g⁻¹ at 3 A g⁻¹), good rate performance (72%) and outstanding cyclic stability (109% after 40,000 cycles). The NCO-Ar/H₂-10//AC asymmetric supercapacitor (ASC) achieves high energy density of 48.6 Wh kg⁻¹ at 799.6 W kg⁻¹ while exhibiting good cycle life (117.5% after 10,000 cycles). The excellent electrochemical performance mainly comes from the round-trip valence change of Cu⁺/Cu²⁺ in the multicomponent hybridization enhance the surface capacitance during the redox process, and the change of electronic microstructure triggered by a large number of oxygen vacancies reduce the adsorption energy of OH⁻ ions of thin nanosheet with crack of surface edge, ensuring electron and ion-transport processes and remitting the structural collapse of material. This work provides a new strategy for improving the cycling stability of transition metal oxide electrode materials.     

Highly Conductive Ti3C2Tx MXene Hybrid Fibers for Flexible and Elastic Fiber‐Shaped Supercapacitors

Fiber‐shaped supercapacitors (FSCs) are promising energy storage solutions for powering miniaturized or wearable electronics. However, the scalable fabrication of fiber electrodes with high electrical conductivity and excellent energy storage performance for use in FSCs remains a challenge. Here, an easily scalable one‐step wet‐spinning approach is reported to fabricate highly conductive fibers using hybrid formulations of Ti₃C₂T_x MXene nanosheets and poly(3,4‐ethylenedioxythiophene):polystyrene sulfonate. This approach produces fibers with a record conductivity of ≈1489 S cm^?1, which is about five times higher than other reported Ti₃C₂T_x MXene‐based fibers (up to ≈290 S cm^?1). The hybrid fiber at ≈70 wt% MXene shows a high volumetric capacitance (≈614.5 F cm^?3 at 5 mV s^?1) and an excellent rate performance (≈375.2 F cm^?3 at 1000 mV s^?1). When assembled into a free‐standing FSC, the energy and power densities of the device reach ≈7.13 Wh cm^?3 and ≈8249 mW cm^?3, respectively. The excellent strength and flexibility of the hybrid fibers allow them to be wrapped on a silicone elastomer fiber to achieve an elastic FSC with 96% capacitance retention when cyclically stretched to 100% strain. This work demonstrates the potential of MXene‐based fiber electrodes and their scalable production for fiber‐based energy storage applications.     

Effect of vanadium doping on MXene-based supercapacitor

The two-dimensional titanium carbide MXene (Ti₃C₂T_x) acts as a promising pseudocapacitive material for supercapacitor electrodes. In this paper, the properties of vanadium-doped titanium carbide MXene (Ti₃C₂T_x) are tuned using a simple hydrothermal method to intercalate the alkali metal adsorbates (K⁺) into the electrode material. The synthesis of the supercapacitor device is carried on glass substrate as well as on a flexible graphite sheet. The X-ray diffraction and scanning electron microscopy are conducted to observe the change in structural properties of vanadium-doped MXene. The cyclic voltammetry and galvanostatic charge–discharge are carried out on Metrohm autolab workstation. The ratio of ammonium vanadate and MXene has been varied from 0.025:0.1 to 0.1:0.1 with a step size of 0.025 to obtain the capacitance results. The results depict that the ratio of 0.025:1 shows the highest capacitance of 258.07 mF/cm² and 1107 mF/cm² in 6 M KOH (20 mV/s) on glass and graphite substrate, respectively. This is mainly because the ratio of 0.025:1 provides the maximum exfoliation which allows electrolyte ions to penetrate in the active material and thus, facilitates fast electron transport resulting in high-performance supercapacitors. Further, this paper also discusses the successful fabrication of the supercapacitor devices on a flexible graphite sheet for the first time. The results show that the capacitance value on flexible substrate is at par with that of the glass substrate. To further understand the increased capacitive properties of vanadium-doped MXene, the processes involving charge transfer and mass transport are investigated by performing electrochemical impedance spectroscopy (EIS). The radius on the EIS plot of vanadium-doped MXene is smaller than that of the undoped DMSO MXene, which indicates that the vanadium doping made the charge transfer easier. Moreover, the capacitance retention of 92.7% and 82.2% is achieved on graphite as well as glass substrate after 3000 cycles.

     

Bath Electrospinning of Continuous and Scalable Multifunctional MXene‐Infiltrated Nanoyarns

Electroactive yarns that are stretchable are desired for many electronic textile applications, including energy storage, soft robotics, and sensing. However, using current methods to produce these yarns, achieving high loadings of electroactive materials and simultaneously demonstrating stretchability is a critical challenge. Here, a one‐step bath electrospinning technique is developed to effectively capture Ti₃C₂T_x MXene flakes throughout continuous nylon and polyurethane (PU) nanofiber yarns (nanoyarns). With up to ≈90 wt% MXene loading, the resulting MXene/nylon nanoyarns demonstrate high electrical conductivity (up to 1195 S cm^?1). By varying the flake size and MXene concentration, nanoyarns achieve stretchability of up to 43% (MXene/nylon) and 263% (MXene/PU). MXene/nylon nanoyarn electrodes offer high specific capacitance in saturated LiClO₄ electrolyte (440 F cm^?3 at 5 mV s^?1), with a wide voltage window of 1.25 V and high rate capability (72% between 5 and 500 mV s^?1). As strain sensors, MXene/PU yarns demonstrate a wide sensing range (60% under cyclic stretching), high sensitivity (gauge factor of ≈17 in the range of 20–50% strain), and low drift. Utilizing the stretchability of polymer nanofibers and the electrical and electrochemical properties of MXene, MXene‐based nanoyarns demonstrate potential in a wide range of applications, including stretchable electronics and body movement monitoring.     

Dual-Defect Engineering of Bidirectional Catalyst for High-Performing Lithium-Sulfur Batteries

Practical applications of lithium-sulfur (Li-S) batteries have been hindered by sluggish reaction kinetics and severe capacity decay during charge-discharge cycling due to the notorious shuttle effect of polysulfide and the unfavored deposition and dissolution of Li₂S. Herein, to address these issues, a double-defect engineering strategy is developed for preparing Co-doped FeP catalyst containing P vacancies on MXene, which effectively improves the bidirectional redox of Li₂S. Mechanism analysis indicates that P vacancy accelerates Li₂S nucleation via increased unsaturated sites, and Co doping generates local electric field to reduce the reaction energy barrier and accelerate Li₂S dissolution. MXene provides highly conductive channels for electron transport, and effectively captures polysulfide. The double-defect catalyst enables an impressive reversible specific capacity of 1297.9 mAh g⁻¹ at 0.2 C, and excellent rate capability of 726.5 mAh g⁻¹ at 4 C. Remarkably, it demonstrates excellent cycling stability with capacity retention of 533.3 mAh g⁻¹ after 500 cycles at 2 C. The results can unlock the double-defect engineering of vacancy induction and heteroatomic doping towards practical Li-S batteries.     

Mott–Schottky Effect in Core–Shell W@WxC Heterostructure: Boosting Both Electronic/Ionic Kinetics for Lithium Storage

The dynamics rate of traditional metal carbides (TMCs) is relatively slow, severely limiting its fast-charging capacity for lithium-ion batteries (LIBs). Herein, the core–shell W@W_xC heterostructure is developed to form Mott–Schottky heterostructure, thereby simultaneously accelerating the electronic and ionic transport kinetics during the charging/discharging process. The W nanoparticles are partially reduced into W_xC to form a particular core–shell structure with abundant heterogeneous interfaces. Benefiting from the Mott–Schottky effect, the electrons at the metal/semiconductor heterointerface can migrate spontaneously to realize an equal work function on both sides. In addition, the independent nanoparticle as well as the unique core–shell structure facilitate the ionic diffusion kinetics. As expected, the W@W_xC electrode exhibits excellent electrochemical stability for LIBs, whose capacity can be maintained at 173.8 mA h g⁻¹ after 1600 cycles at a high current density of 5 A g⁻¹. When assembled into a full cell, it can achieve an energy density of 360.2 Wh kg⁻¹. This work presents a new avenue to promote the electronic and ionic kinetics for LIBs anodes by constructing the unique Mott–Schottky heterostructure.     

Engineering Interfacial Built-in Electric Field in Polymetallic Phosphide Heterostructures for Superior Supercapacitors and Electrocatalytic Hydrogen Evolution

Herein, a patterned rod-like CoP@NiCoP core-shell heterostructure is designed to consist of CoP nanowires cross-linked with NiCoP nanosheets in tight strings. The interfacial interaction within the heterojunction between the two components generates a built-in electric field that adjusts the interfacial charge state and create more active sites, accelerating the charge transfer and improving supercapacitor and electrocatalytic performance. The unique core-shell structure suppresses the volume expansion during charging and discharging, achieving excellent stability. As a result, CoP@NiCoP exhibits a high specific capacitance of 2.9 F cm⁻² at a current density of 3 mA cm⁻² and a high ion diffusion rate (D_ion is 2.95 × 10⁻¹⁴ cm² s⁻¹) during charging/discharging. The assembled asymmetric supercapacitor CoP@NiCoP//AC exhibits a high energy density of 42.2 Wh kg⁻¹ at a power density of 126.5 W kg⁻¹ and excellent stability with a capacitance retention rate of 83.8% after 10 000 cycles. Furthermore, the modulated effect induced by the interfacial interaction also endows the self-supported electrode with excellent electrocatalytic HER performance with an overpotential of 71 mV at 10 mA cm⁻². This research may provide a new perspective on the generation of built-in electric field through the rational design of heterogeneous structures for improving the electrochemical and electrocatalytical performance.     

Self-assembled Ti3C2Tx-MXene/PTh composite electrodes for electrochemical capacitors

Recently, MXene are being extensively utilized as an electrode material for electrochemical capacitors owing to its excellent electrochemical performance. Furthermore, its excellent properties are enhanced by compounding it with other materials as the electrode material of electrochemical capacitor. In this study, MXene has been obtained by selective etching, Polythiophene (PTh) was prepared by chemical oxidative polymerization, and MXene/PTh composites with different mass ratios have been synthesized by the vacuum filtration self-assembly method. MXene nanosheets have the comprehensive function of combining PTh nanoparticles, and acting as flexible substrates. PTh nanoparticles can provide high pseudo-capacitance and inhibit the stacking of MXene, thus achieving a good synergistic effect. The results demonstrate that the M/PTh-3 composite has the best capacitance with a maximum value of 265.96 F g^?1. The specific capacitance remains at 91.5% even after 500 cycles, which demonstrates that the composite electrode is a promising material for the high-performance electrochemical capacitor applications.

     

Multifunctional MoSe2@MXene Heterostructure-Decorated Cellulose Fabric for Wearable Thermal Therapy

A booming demand for wearable electronic devices urges the development of multifunctional smart fabrics. However, it is still facing a challenge to fabricate multifunctional smart fabrics with satisfactory mechanical property, excellent Joule heating performance, highly efficient photothermal conversion, outstanding electromagnetic shielding effectiveness, and superior anti-bacterial capability. Here, a MoSe₂@MXene heterostructure-based multifunctional cellulose fabric is fabricated by depositing MXene nanosheets onto cellulose fabric followed by a facile hydrothermal method to grow MoSe₂ nanoflakes on MXene layers. A low-voltage Joule heating therapy platform with rapid Joule heating response (up to 230 °C in 25 s at a supplied voltage of 4 V) and stable performance under repeated bending cycles (up to 1000 cycles) is realized. Besides, the multifunctional fabric also exhibits excellent photothermal performance (up to 130 °C upon irradiation for 25 s with a light intensity of 400 mW cm⁻²), outstanding electromagnetic interference shielding effectiveness (37 dB), and excellent antibacterial performances (>90% anti-bacterial rate toward Escherichia coli, Bacillus subtilis, and Staphylococcus aureus). This work offers an efficient avenue to fabricate multifunctional wearable thermal therapy devices for mobile healthcare and personal thermal management.     

Reconfiguring the Electronic Structure of Heteroatom Doped Carbon Supported Bimetallic Oxide@Metal Sulfide Core–Shell Heterostructure via In Situ Nb Incorporation toward Extrinsic Pseudocapacitor

High-energy-density battery-type materials have sparked considerable interest as supercapacitors electrode; however, their sluggish charge kinetics limits utilization of redox-active sites, resulting in poor electrochemical performance. Here, the unique core–shell architecture of metal organic framework derived N–S codoped carbon@Co_xS_y micropetals decorated with Nb-incorporated cobalt molybdate nanosheets (Nb-CMO₄@C_xS_yNC) is demonstrated. Coordination bonding across interfaces and π–π stacking interactions between CMO₄@C_xS_y and N and, S–C can prevent volume expansion during cycling. Density functional theory analysis reveals that the excellent interlayer and the interparticle conductivity imparted by Nb doping in heteroatoms synergistically alter the electronic states and offer more accessible species, leading to increased electrical conductivity with lower band gaps. Consequently, the optimized electrode has a high specific capacity of 276.3 mAh g⁻¹ at 1 A g⁻¹ and retains 98.7% of its capacity after 10 000 charge–discharge cycles. A flexible quasi-solid-state SC with a layer-by-layer deposited reduced graphene oxide /Ti₃C₂T_X anode achieves a specific energy of 75.5 Wh kg⁻¹ (volumetric energy of 1.58 mWh cm⁻³) at a specific power of 1.875 kWh kg⁻¹ with 96.2% capacity retention over 10 000 charge–discharge cycles.     

Electronic Structure Engineered Heteroatom Doped All Transition Metal Sulfide Carbon Confined Heterostructure for Extrinsic Pseudocapacitor

Ultra-high energy density battery-type materials are promising candidates for supercapacitors (SCs); however, slow ion kinetics and significant volume expansion remain major barriers to their practical applications. To address these issues, hierarchical lattice distorted α-/γ-MnS@Co_xS_y core-shell heterostructure constrained in the sulphur (S), nitrogen (N) co-doped carbon (C) metal-organic frameworks (MOFs) derived nanosheets (α-/γ-MnS@Co_xS_y@N, S C) have been developed. The coordination bonding among Co_xS_y, and α-/γ-MnS nanoparticles at the interfaces and the π–π stacking interactions developed across α-/γ-MnS@Co_xS_y and N, S C restrict volume expansion during cycling. Furthermore, the porous lattice distorted heteroatom-enriched nanosheets contain a sufficient number of active sites to allow for efficient electron transportation. Density functional theory (DFT) confirms the significant change in electronic states caused by heteroatom doping and the formation of core-shell structures, which provide more accessible species with excellent interlayer and interparticle conductivity, resulting in increased electrical conductivity. . The α-/γ-MnS@Co_xS_y@N, S C electrode exhibits an excellent specific capacity of 277 mA hg⁻¹ and cycling stability over 23 600 cycles. A quasi-solid-state flexible extrinsic pseudocapacitor (QFEPs) assembled using layer-by-layer deposited multi-walled carbon nanotube/Ti₃C₂T_X nanocomposite negative electrode. QFEPs deliver specific energy of 64.8 Wh kg⁻¹ (1.62 mWh cm⁻³) at a power of 933 W kg⁻¹ and 92% capacitance retention over 5000 cycles.