Intercalation of Metal Ions into Ti3C2Tx MXene Electrodes for High‐Areal‐Capacitance Microsupercapacitors with Neutral Multivalent Electrolytes

Microsupercapacitors (MSCs) with neutral multivalent electrolytes are safer, cheaper, and exhibit higher theoretical energy densities compared with the MSCs with acidic and alkaline electrolytes. Multivalent charge carriers (e.g., Mg²⁺, Zn²⁺) in the MSCs with Ti₃C₂T_x MXene electrodes have not been demonstrated, which could theoretically achieve higher specific capacitances and energy densities. However, because of the larger size of multivalent charge carriers, the MXene electrodes require further modifications to facilitate reversible electrochemical reactions. Herein, through spontaneous intercalation of various metal ions into MXene multilayers, twelve metal ion intercalated MXene electrodes (Mⁿ⁺‐MXene) are fabricated and demonstrate improved electrochemical performance. Different nanopillar effects are observed between divalent Be²⁺ and trivalent Al³⁺ intercalants, which are systematically investigated by electrochemical impedance spectroscopy and molecular dynamics simulation. Among all Mⁿ⁺‐MXene electrodes, the Be²⁺‐MXene electrode largely facilitates the charge‐transfer process with minimal disturbance of electrolyte diffusion rates, showing improved specific capacitances and high rate performance in univalent (Li₂SO₄, Na₂SO₄, K₂SO₄) and multivalent electrolytes (BeSO₄, MgSO₄, ZnSO₄). Finally, flexible Be²⁺‐MXene MSCs with neural ZnSO₄ gel electrolytes are fabricated, demonstrating superior areal capacitances (77.2 mF cm^?2) and high energy density (3.86 μWh cm^?2 at 0.12 mW cm^?2) together with high user safety.     

Controllable Patterning of Porous MXene (Ti3C2) by Metal-Assisted Electro-Gelation Method

Since discovered in 2011, transition metal carbides or nitrides (MXenes) have attracted enormous attention due to their unique properties. Morphology regulation strategies assembling 2D MXene sheets into 3D architecture have endowed the as-formed porous MXene with a better performance in various fields. However, the direct patterning strategy for the porous MXene into integration with multifunctional and multichannel electronic devices still needs to be investigated. The metal-assisted electro-gelation method the authors propose can directly generate porous-structured MXene hydrogel with a tunable feature. By electrolyzing the sacrificial metal, the released metal cations initiate the electro-gelation process during which electrostatic interactions occur between cations and the MXene sheets. A high spatial resolution down to micro-meter level is achieved utilizing the method, enabling high-performance hydrogels with more complex architectures. Electronics prepared through this metal-assisted electro-gelation process have shown promising applications of the porous MXene in energy and biochemical sensing fields. Energy storage devices with a capacitance at 33.3 mF cm⁻² and biochemical sensors show prominent current responses towards metabolites (sensitivity of H₂O₂: 165.6  µ A mm ⁻¹ cm⁻²; sensitivity of DA: 212 nA  µ m ⁻¹ cm⁻²), suggesting that the metal-assisted electro-gelation method will become a prospective technique for advanced fabrication of MXene-based devices.     

Metal Single-Site Molecular Complex–MXene Heteroelectrocatalysts Interspersed Graphene Nanonetwork for Efficient Dual-Task of Water Splitting and Metal–Air Batteries

Development of multifunctional electrocatalysts with high efficiency and stability is of great interest in recent energy conversion technologies. Herein, a novel heteroelectrocatalyst of molecular iron complex (Fe_MC)-carbide MXene (Mo₂TiC₂T_x) uniformly embedded in a 3D graphene-based hierarchical network (GrH) is rationally designed. The coexistence of Fe_MC and MXene with their unique interactions triggers optimum electronic properties, rich multiple active sites, and favorite free adsorption energy for excellent trifunctional catalytic activities. Meanwhile, the highly porous GrH effectively promotes a multichannel architecture for charge transfer and gas/ion diffusion to improve stability. Therefore, the Fe_MC–MXene/GrH results in superb performances towards oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and hydrogen evolution reaction (HER) in alkaline medium. The practical tests indicate that Zn/Al–air batteries derived from Fe_MC–MXene/GrH cathodic electrodes produce high power densities of 165.6 and 172.7 mW cm⁻², respectively. Impressively, the liquid-state Zn–air battery delivers excellent cycling stability of over 1100 h. In addition, the alkaline water electrolyzer induces a low cell voltage of 1.55 V at 10 mA cm⁻² and 1.86 V at 0.4 A cm⁻² in 30 wt.% KOH at 80 °C, surpassing recent reports. The achievements suggest an exciting multifunctional electrocatalyst for electrochemical energy applications.     

Nature-Inspired Interconnected Macro/Meso/Micro-Porous MXene Electrode

The geometric multiplication development of MXene has promoted it to become a star material in numerous applications including, but not limited to, energy storage. It is found that pore structure modulation engineering can improve the inherent properties of MXene, in turn significantly enhancing its electrochemical performance. However, most of the current works have focused on exploring the structure-effective relationships of the single-scale pore structure regulation of MXene. Inspired by Murray's law from nature where a highly graded structure of the organisms is discovered and used to achieve effective diffusion and maximize mass transfer, a hierarchically interconnected porous MXene electrode across micro-meso-macroporous is constructed. This MXene-based electrode provides large amounts of active sites while greatly shortening the ion diffusion channel. Finally, the zinc ion microcapacitor based on this MXene electrode exhibits an ultrahigh area-specific capacitance up to 410 mF cm⁻² and an energy density up to 103 µWh cm⁻² at a power density of 2100 µW cm⁻². The areal energy density outperforms the currently reported zinc ion microcapacitors. This study supports an effective strategy for electrode materials (including but not limited to MXene) to achieve ultra-short ion diffusion channels and maximum transport efficiency for next-generation high-performance energy storage.     

Reassembly of MXene Hydrogels into Flexible Films towards Compact and Ultrafast Supercapacitors

The freestanding MXene films are promising for compact energy storage ascribing to their high pseudocapacitance and density, yet the sluggish ion transport caused by the most densely packed structure severely hinders their rate capability. Here, a reassembly strategy for constructing freestanding and flexible MXene-based film electrodes with a tunable porous structure is proposed, where the Ti₃C₂T_x microgels disassembled from 3D structured hydrogel are reassembled together with individual Ti₃C₂T_x nanosheets in different mass ratios to form a densely packed 3D network in microscale and a film morphology in macroscale. The space utilization of produced film can be maximized by a good balance of the density and porosity, resulting in a high volumetric capacitance of 736 F cm⁻³ at an ultrahigh scan rate of 2000 mV s⁻¹. The fabricated supercapacitor yields a superior energy density of 40 Wh L⁻¹ at a power density of 0.83 kW L⁻¹, and an energy density of 21 Wh L⁻¹ can be still maintained even when the power density reaches 41.5 kW L⁻¹, which are the highest values reported to date for symmetric supercapacitors in aqueous electrolytes. More promisingly, the reassembled films can be used as electrodes of flexible supercapacitors, showing excellent flexibility and integrability.     

Flexible Carbon Dots-Intercalated MXene Film Electrode with Outstanding Volumetric Performance for Supercapacitors

2D MXenes have emerged as promising supercapacitor electrode materials due to their metallic conductivity, pseudo-capacitive mechanism, and high density. However, layer-restacking is a bottleneck that restrains their ionic kinetics and active site exposure. Herein, a carbon dots-intercalated strategy is proposed to fabricate flexible MXene film electrodes with both large ion-accessible active surfaces and high density through gelation of calcium alginate (CA) within the MXene nanosheets followed by carbonization. The formation of CA hydrogel within the MXene nanosheets accompanied by evaporative drying endow the MXene/CA film with high density. In the carbonization process, the CA-derived carbon dots can intercalate into the MXene nanosheets, increasing the interlayer spacing and promoting the electrolytic diffusion inside the MXene film. Consequently, the carbon dots-intercalated MXene films exhibit high volumetric capacitance (1244.6 F cm⁻³ at 1 A g⁻¹), superior rate capability (662.5 F cm⁻³ at 1000 A g⁻¹), and excellent cycling stability (93.5% capacitance retention after 30 000 cycles) in 3 m H₂SO₄. Additionally, an all-solid-state symmetric supercapacitor based on the carbon dots-intercalated MXene film achieves a high volumetric energy density of 27.2 Wh L⁻¹. This study provides a simple yet efficient strategy to construct high-volumetric performance MXene film electrodes for advanced supercapacitors.     

Asymmetric Sandwich Janus Structure for High-Performance Textile-Based Thermo–Hydroelectric Generators Toward Human Health Monitoring

Textile-based generators that can convert low-grade energy from the human body or environment into sustainable electricity have generated immense scientific interest in self-powered wearable applications. However, their low power density and environmental suitability have extremely restricted their portable applications in complex and mutable environments. Herein, an asymmetric sandwich structure between molybdenum disulfide (MoS₂)-carbonized silks (MCs) and MoS₂/MXene–Cottons (MMCs) to construct efficient thermo–hydroelectric generators (THEGs) that synergistically harvest heat-moisture energy to generate considerable electricity is rationally designed. Notably, the large surface area of MoS₂/MXene van der Waals heterojunctions (vdWhs) enables efficient charge collection, and the vertical MoS₂ nanosheet arrays supply abundant nanochannels for a highly efficient hydration effect, generating an output power density of 32.26 µW cm⁻² after wetting with deionized water. Combined with the sensitive temperature recognition ability with a Seebeck coefficient of 23.5 µV K⁻¹, the application possibilities of these prepared THEGs in the mutual conversion of fingertip temperature/language, and the monitoring of the human physiological state is foresee.     

Multilevel Structure Engineered Lead-Free Piezoceramics Enabling Breakthrough in Energy Harvesting Performance for Bioelectronics

The prevalence of wearable/implantable medical electronics together with the rapid development of the Internet of Medicine Things call for the advancement of biocompatible, reliable, and high-efficiency energy harvesters. However, most current harvesters are based on toxic lead-based piezoelectric materials, raising biological safety concerns. What hinders the application of lead-free piezoelectric energy harvesters (PEHs) is the low power output, where the key challenge lies in obtaining a high piezoelectric voltage constant (g₃₃) and harvesting figure of merit (d₃₃ × g₃₃). Here, micron pores are introduced into phased boundary engineered high-performance (K, Na)NbO₃-based ceramic matrix, resulting in the state-of-the-art g₃₃ and the highest d₃₃ × g₃₃ values of 57.3 × 10⁻³ Vm N⁻¹ and 20887 × 10⁻¹⁵ m² N⁻¹ in lead-free piezoceramics, respectively. Concomitantly, ultrahigh energy harvesting performances are obtained in porous ceramic PEHs, with output voltage and power density of 200 V and 11.6 mW cm⁻² under instantaneous force impact and an average charging rate of 14.1 µW under high-frequency (1 MHz) ultrasound excitation, far outperforming previously reported PEHs. Porous ceramic PEHs are further developed into wearable and bio-implantable devices for human motion sensing and percutaneous ultrasound power transmission, opening avenues for the design of next-generation eco-friendly WIMEs.     

Active Site Implantation for Ni(OH)2 Nanowire Network Achieves Superior Hybrid Seawater Electrolysis at 1 A cm−2 with Record-Low Cell Voltage

Direct seawater electrolysis provides a grand blueprint for green hydrogen (H₂) technology, while the high energy consumption has severely hindered its industrialization. Herein, a promising active site implantation strategy is reported for Ni(OH)₂ nanowire network electrode on nickel foam substrate by Ru doping (denoted as Ru Ni(OH)₂ NW²/NF), which can act as a dual-function catalyst for hydrazine oxidation and hydrogen evolution, achieving an ultralow working potential of 114.6 mV to reach 1000 mA cm⁻² and a small overpotential of 30 mV at 10 mA cm⁻², respectively. Importantly, using the two-electrode hydrazine oxidation assisted seawater electrolysis, it can drive a large current density of 500 mA cm⁻² at 0.736 V with over 200 h stability. To demonstrate the practicability, a home-made flow electrolyzer is constructed, which can realize the industry-level rate of 1 A cm⁻² with a record-low voltage of 1.051 V. Theoretical calculations reveal that the Ru doping activates Ni(OH)₂ by upgrading d-band centers, which raises anti-bonding energy states and thus strengthens the interaction between adsorbates and catalysts. This study not only provides a novel rationale for catalyst design, but also proposes a feasible strategy for direct alkaline seawater splitting toward sustainable, yet energy-saving H₂ production.     

Flexible Transparent Bifunctional Capacitive Sensors with Superior Areal Capacitance and Sensing Capability based on PEDOT:PSS/MXene/Ag Grid Hybrid Electrodes

Flexible transparent supercapacitors (FTSs) have aroused considerable attention. Nonetheless, balancing energy storage capability and transparency remains challenging. Herein, a new type of FTSs with both excellent energy storage and superior transparency is developed based on PEDOT:PSS/MXene/Ag grid ternary hybrid electrodes. The hybrid electrodes can synergistically utilize the high optoelectronic properties of Ag grids, the excellent capacitive performance of MXenes, and the superior chemical stability of PEDOT:PSS, thus, simultaneously demonstrating excellent optoelectronic properties (T: ≈89%, R_s: ≈39 Ω sq⁻¹), high areal specific capacitance, superior mechanical softness, and excellent anti-oxidation capability. Due to the excellent comprehensive performances of the hybrid electrodes, the resulting FTSs exhibit both high optical transparency (≈71% and ≈60%) and large areal specific capacitance (≈3.7 and ≈12 mF cm⁻²) besides superior energy storage capacity (P: 200.93, E: 0.24 µWh cm⁻²). Notably, the FTSs show not only excellent energy storage but also exceptional sensing capability, viable for human activity recognition. This is the first time to achieve FTSs that combine high transparency, excellent energy storage and good sensing all-in-one, which make them stand out from conventional flexible supercapacitors and promising for next-generation smart flexible energy storage devices.     

Triple Interface Optimization of Ru-based Electrocatalyst with Enhanced Activity and Stability for Hydrogen Evolution Reaction

A challenging task is to promote Ru atom economy and simultaneously alleviate Ru dissolution during the hydrogen evolution reaction (HER) process. Herein, Ru nanograins (≈1.7 nm in size) uniformly grown on 1T-MoS₂ lace-decorated Ti₃C₂T_x MXene sheets (Ru@1T-MoS₂-MXene) are successfully synthesized with three types of interfaces (Ru/MoS₂, Ru/MXene, and MoS₂/MXene). It gives high mass activity of 0.79 mA µg_Ru⁻¹ at an overpotential of 100 mV, which is ≈36 times that of Ru NPs. It also has a much smaller Ru dissolution rate (9 ng h⁻¹), accounting for 22% of the rate for Ru NPs. Electrochemical tests, scanning electrochemical microscopy measurements combined with DFT calculations disclose the role of triple interface optimization in improved activity and stability. First, 2D MoS₂ and MXene can well disperse and stabilize Ru grains, giving larger electrochemical active area. Then, Ru/MoS₂ interfaces weakening H^* adsorption energy and Ru/MXene interfaces enhancing electrical conductivity, can efficiently improve the activity. Next, MoS₂/MXene interfaces can protect MXene sheet edges from oxidation and keep 1T-MoS₂ phase stability during the long-term catalytic process. Meanwhile, Ru@1T-MoS₂-MXene also displays superior activity and stability in neutral and alkaline media. This work provides a multiple-interface optimization route to develop high-efficiency and durable pH-universal Ru-based HER electrocatalysts.     

Floating Catalyst Chemical Vapor Deposition Patterning Nitrogen-Doped Single-Walled Carbon Nanotubes for Shape Tailorable and Flexible Micro-Supercapacitors

Micro-supercapacitors (MSCs) as high-power density energy storage units are designed to meet the booming development of flexible electronics, requiring simple and fast fabrication technology. Herein, a fast and direct solvent-free patterning method is reported to fabricate shape-tailorable and flexible MSCs by floating catalyst chemical vapor deposition (FCCVD). The nitrogen-doped single-walled carbon nanotubes (N-SWCNTs) are directly deposited on a patterned filter by FCCVD with designable patterns and facilely dry-transferred on versatile substrates. The obtained MSCs deliver an excellent areal capacitance of 3.6 mF cm⁻² and volumetric capacitance of 98.6 F cm⁻³ at a scan rate of 5 mV s⁻¹ along with excellent long-term cycle stability over 125 000 circles. Furthermore, the MSCs show good performance uniformity, which can be readily integrated via connection in parallel or series to deliver a stable high voltage (4 V with five serially connected devices) and large capacitance (5.1 mF with five parallel devices) at a scan rate of 100 mV s⁻¹, enabling powering the light emitting displays. Therefore, this method blazes the trail of directly preparing flexible, shape-customizable, and high-performance MSCs.     

Lamellar MXene Composite Aerogels with Sandwiched Carbon Nanotubes Enable Stable Lithium–Sulfur Batteries with a High Sulfur Loading

Realizing long cycling stability under a high sulfur loading is an essential requirement for the practical use of lithium–sulfur (Li–S) batteries. Here, a lamellar aerogel composed of Ti₃C₂T_x MXene/carbon nanotube (CNT) sandwiches is prepared by unidirectional freeze-drying to boost the cycling stability of high sulfur loading batteries. The produced materials are denoted parallel-aligned MXene/CNT (PA-MXene/CNT) due to the unique parallel-aligned structure. The lamellae of MXene/CNT/MXene sandwich form multiple physical barriers, coupled with chemical trapping and catalytic activity of MXenes, effectively suppressing lithium polysulfide (LiPS) shuttling under high sulfur loading, and more importantly, substantially improving the LiPS confinement ability of 3D hosts free of micro- and mesopores. The assembled Li–S battery delivers a high capacity of 712 mAh g⁻¹ with a sulfur loading of 7 mg cm⁻², and a superior cycling stability with 0.025% capacity decay per cycle over 800 cycles at 0.5 C. Even with sulfur loading of 10 mg cm⁻², a high areal capacity of above 6 mAh cm⁻² is obtained after 300 cycles. This work presents a typical example for the rational design of a high sulfur loading host, which is critical for the practical use of Li–S batteries     

Overcoming Anode Instability in Solid-State Batteries through Control of the Lithium Metal Microstructure

Enabling the lithium metal anode (LMA) in solid-state batteries (SSBs) is the key to developing high energy density battery technologies. However, maintaining a stable electrode–electrolyte interface presents a critical challenge to high cycling rate and prolonged cycle life. One such issue is the interfacial pore formation in LMA during stripping. To overcome this, either higher stack pressure or binary lithium alloy anodes are used. Herein, it is shown that fine-grained (d = 20 µm) polycrystalline LMA can avoid pore formation by exploiting the microstructural dependence of the creep rates. In a symmetric cell set-up, i.e., LiǀLi_6.25Al_0.25La₃Zr₂O₁₂(LLZO)ǀLi, fine-grained LMA achieves > 11.0 mAh cm⁻² compared to ≈ 3.6 mAh cm⁻² for coarse-grained LMA (d = 295 µm) at 0.1 mA cm⁻² and at moderate stress of 2.0 MPa. Smaller diffusion lengths (≈ 20 µm) and higher diffusivity pathway along dislocations (D_d ≈ 10⁻⁷ cm² s⁻¹), generated during cell fabrication, result in enhanced viscoplastic deformation in fine-grained polycrystalline LMA. The electrochemical performances corroborate well with estimated creep rates. Thus, microstructural control of LMA can significantly reduce the required stack pressure during stripping. These results are particularly relevant for “anode-free” SSBs wherein both the microstructure and the mechanical state of the lithium are critical parameters.     

Sintered Polycrystalline BiVO4 Pellet for Stable X-Ray Detector with Low Detection Limit

Semiconductors based on Bi element show large attenuation coefficients to X-ray photons and have been recognized as candidates for X-ray detectors. However, the application of stable Bi-based oxide materials to X-ray detectors has been rarely investigated. In this research, the X-ray response of a BiVO₄ pellet has been studied. It has been found that the BiVO₄ pellet has a large resistivity of 1.3 × 10¹² Ω cm, negligible current drift of 6.18 × 10⁻⁸ nA cm⁻¹ s⁻¹ V⁻¹ under electrical bias and mobility lifetime product, µτ, of 1.75 × 10⁻⁴ cm² V⁻¹, which renders the pellet with an X-ray sensitivity of 241.3 µC Gy_air⁻¹ cm⁻² and a detection limit of 62 nGy_air s⁻¹ under 40 KVp X-ray illumination and 40 V bias voltage. The BiVO₄ pellet also shows operational stability under steady X-ray illumination with total dose of 2.01 Gy_air, equal to the dose of 20 000 medical chest X-ray inspections. This research reveals the potential application of BiVO₄ in X-ray detection devices and inspires further research in this area.     

Efficient Water Splitting System Enabled by Multifunctional Platinum-Free Electrocatalysts

Tremendous research efforts have been focused on the development of a water splitting system (WSS) to harvest hydrogen fuels, but currently available WSSs are complicated and cost-ineffective mainly due to the applications of noble platinum or different electrocatalysts. Herein, a novel WSS comprising electricity generation from solar panels, electricity storage in rechargeable zinc–air batteries (ZABs), and water splitting in electrolyzers, enabled by hybrid cobalt nanoparticles/N-doped carbon embellished on carbon cloth (Co–NC@CC) as multifunctional platinum-free electrocatalysts is reported. Consequently, the Co–NC@CC electrode presents excellent trifunctional electrocatalytic activity with an onset potential of 0.94 V for oxygen reduction reaction, and an overpotential of 240 and 73 mV to achieve a current density of 10 mA cm⁻² for oxygen and hydrogen evolution reactions, respectively. For a proof-of-concept application, a rechargeable ZAB assembled from the high-performance Co–NC@CC air cathode exhibits a high open circuit potential of 1.63 V and a superior energy density of 1051 Wh kg⁻¹_Zn. Furthermore, an overall water splitting electrolyzer constructed by the symmetrical Co–NC@CC electrodes delivers a current density of 10 mA cm⁻² at a low cell voltage of 1.57 V. Such a solar-powered WSS can harvest hydrogen day and night, demonstrating a potential for application in sustainable renewable energy.     

Transparent and Flexible Mn1−x−y(CexLay)O2−δ Ultrathin-Film Device for Highly-Stable Pseudocapacitance Application

Control over the fabrication of state-of-the-art portable pseudocapacitors with the desired transparency, mechanical flexibility, capacitance, and durability is challenging, but if resolved will have fundamental implications. Here, defect-rich Mn_1−x−y(Ce_xLa_y)O_2−δ ultrathin films with controllable thicknesses (5–627 nm) and transmittance (≈29–100%) are fabricated via an electrochemical chronoamperometric deposition using a aqueous precursor derived from end-of-life nickel-metal hydride batteries. Due to percolation impacts on the optoelectronic properties of ultrathin films, a representative Mn_1−x−y(Ce_xLa_y)O_2−δ film with 86% transmittance exhibits an outstanding areal capacitance of 3.4 mF cm⁻², mainly attributed to the intercalation/de-intercalation of anionic O²⁻ through the atomic tunnels of the stratified Mn_1−x−y(Ce_xLa_y)O_2−δ crystallites. Furthermore, the Mn_1−x−y(Ce_xLa_y)O_2−δ thin-film device exhibits excellent capacitance retention of ≈90% after 16 000 cycles. Such stability is associated with intervalence charge transfer occurring among interstitial Ce/La cations and Mn oxidation states within the Mn_1−x−y(Ce_xLa_y)O_2−δ structure. The energy and power densities of the transparent flexible Mn_1−x−y(Ce_xLa_y)O_2−δ full-cell pseudocapacitor device, is measured to be 0.088 μWh cm⁻² and 843 µW cm⁻², respectively. These values show insignificant changes under vigorous twisting and bending to 45–180° confirming these value-added materials are intriguing alternatives for size-sensitive energy storage devices.     

Scalable Production of Graphene Inks via Wet‐Jet Milling Exfoliation for Screen‐Printed Micro‐Supercapacitors

The miniaturization of energy storage units is pivotal for the development of next‐generation portable electronic devices. Micro‐supercapacitors (MSCs) hold great potential to work as on‐chip micro‐power sources and energy storage units complementing batteries and energy harvester systems. Scalable production of supercapacitor materials with cost‐effective and high‐throughput processing methods is crucial for the widespread application of MSCs. Here, wet‐jet milling exfoliation of graphite is reported to scale up the production of graphene as a supercapacitor material. The formulation of aqueous/alcohol‐based graphene inks allows metal‐free, flexible MSCs to be screen‐printed. These MSCs exhibit areal capacitance (C_areal) values up to 1.324 mF cm^?2 (5.296 mF cm^?2 for a single electrode), corresponding to an outstanding volumetric capacitance (C_vol) of 0.490 F cm^?3 (1.961 F cm^?3 for a single electrode). The screen‐printed MSCs can operate up to a power density above 20 mW cm^?2 at an energy density of 0.064 µWh cm^?2. The devices exhibit excellent cycling stability over charge–discharge cycling (10 000 cycles), bending cycling (100 cycles at a bending radius of 1 cm) and folding (up to angles of 180°). Moreover, ethylene vinyl acetate‐encapsulated MSCs retain their electrochemical properties after a home‐laundry cycle, providing waterproof and washable properties for prospective application in wearable electronics.     

Achieving Superior Thermoelectric Performance in Ge4Se3Te via Symmetry Manipulation with I–V–VI2 Alloying

Although orthorhombic GeSe is predicted to have an ultrahigh figure of merit, ZT ≈ 2.5, up to now, the highest experimental value is ≈0.2 due to the low carrier concentration (n_H ≈ 10¹⁸ cm⁻³). Improving symmetry is an effective approach for enhancing the ZT of GeSe-based materials. With Te-alloying, Ge₄Se₃Te displays the two-dimensional hexagonal structure and high n_H ≈ 1.23 × 10²¹ cm⁻³. Interestingly, Ge₄Se₃Te transformed from the hexagonal into the rhombohedral phase with only ≈2% I–V–VI₂-alloying (I = Li, Na, K, Cu, Ag; V = Sb, Bi; VI = Se, Te). According to the calculated results of Ge_0.82Ag_0.09Bi_0.09Se_0.614Te_0.386 single-crystal grown via AgBiTe₂-alloying, it exhibits a higher valley degeneracy than the hexagonal Ge₄Se₃Te. For instance, AgBiTe₂-alloying induces a strong band convergence and band inversion effect, resulting in a significantly enhanced Seebeck coefficient and power factor with a similar n_H from 17 µV K⁻¹ and 0.63 µW cm⁻¹ K⁻² for pristine Ge₄Se₃Te to 124 µV K⁻¹ and 5.97 µW cm⁻¹ K⁻² for 12%AgBiTe₂-alloyed sample, respectively. Moreover, the sharply reduced phonon velocity, nano-domain wall structure, and strong anharmonicity lead to low lattice thermal conductivity. As a result, a record-high average ZT ≈0.95 over 323–773 K with an excellent ZT ≈ 1.30 is achieved at 723 K.     

Synergistic Enhancement of Luminescent and Ferroelectric Properties through Multi-Clipping of Tetraphenylethenes

Synergistically enhancing luminescent and ferroelectric ( SELF ) properties are observed from a tetraphenylethene ( TP ) substituted with clipping groups ( C ), where the C is consisting of a 4-[3,5-bis-(3-decyloxy-styryl)-styryl]-phenyl ( DOS ) unit. The DOS units of TPCn are self-assembled via intermolecular interaction to clip themselves and induce TP aggregation, as evidenced by clip-induced quenching of emission at DOS units ( E _clip ) accompanied by aggregation-induced emission enhancement of TPs ( E _AIE ). TPC4 demonstrates strong photoluminescence in a dilute chloroform solution and large E_AIE in aqueous (>50%) THF solution. TPCn demonstrates SELF properties in film state, with high quantum yields of photoluminescence (>80%) and ferroelectric switching. Due to the introduction of four clips, TPC4 has a higher remnant polarization ( P _r  =  2.27 µC cm⁻²) at room temperature than TPC1. TPC4 is successfully employed in a light-emitting electrochemical cell to achieve over 1290 cd m⁻² under pulsed current conditions. The TPC4 film on a flexible substrate produced a piezoelectric output voltage of up to 0.13 V and a current density of 1.14 nA cm⁻² upon bending. These results indicate that the side chain clipping and TP aggregation resulted in unprecedented flexible SELF properties in a single compound, offering simultaneous enhancement of electroluminescence, mechanical sensitivity, and energy harvesting capacity.