EcoMat最新文献

Lithium-ion batteries are integral to the advancement of electric vehicles and energy storage systems. Among cathode materials, lithium iron phosphate (LiFePO₄, LFP) has gained significant attention due to its low cost and stable lifespan. However, the relatively low energy density of LFP presents a critical challenge. To address this, a thick electrode strategy has been proposed, which reduces the proportion of electrochemically inactive components and increases the loading of active material, thereby enhancing energy density. Despite its potential, thick LFP electrodes suffer from severe capacity degradation during cycling, and the underlying mechanisms remain poorly understood. In this study, we compare reference and thick electrodes with active material loadings of 9 mg/cm² and 18 mg/cm², respectively. Through various analysis techniques such as electrochemical tests, scanning electron microscopy, x-ray photoelectron spectroscopy, and synchrotron-based x-ray analyses, we identify that ionic conductivity is the primary kinetic limitation in thick LFP electrodes rather than electronic conductivity, leading to inhomogeneous reactions. Furthermore, side reactions with the electrolyte in the top layer of the thick electrode impose additional kinetic constraints. This work provides critical insights into electrode design strategies and performance optimization for thick LFP electrode systems.

Zinc, in a complex form, is one of the main components of the flue dust formed during the hot-dip galvanizing (HDG). Its disposal not only causes economic losses but also poses significant environmental challenges. In alignment with circular economy, the utilization of such industrial residues in value-added applications becomes vital. Herein, using HDG flue dust as an input material, a novel approach for synthesizing Fe-doped ZnO/carbon-based composite anode materials for lithium-ion batteries (LIBs) is proposed. In this scope, a three-step process comprising neutral leaching, calcination, and ball milling is employed for the fabrication. Neutral leaching is optimized to enrich the hot-dip galvanizing (HDG) flue dust residue with zinc and iron while simultaneously reducing the concentrations of ammonia and chlorine. The optimal leaching conditions (95.7 wt% Zn retention efficiency) are determined to be 80°C, a solid to liquid ratio of 1:100, and a leaching time of 1 h at 750 rpm. Later, the solid residue is subjected to thermal treatment at 500°C for 4 h, resulting in Fe-doped ZnO powder. Lastly, the synthesized Fe-doped ZnO powder is mechanically ball-milled with activated carbon (AC) at three different weight ratios: Fe-ZnO:C = 1:1, 2:1, and 3:1. Fe-ZnO:C = 3:1 achieves the highest capacity and the best retention: at the 1st and 100th cycles, it delivers 1760.72 and 592.68 mAh g⁻¹, respectively. The enhanced performance of the composite is attributed to its unique properties in morphology, structure, and chemistry.

Sodium-ion batteries (SIBs) are a promising alternative to lithium-ion batteries due to their cost-effectiveness and abundant sodium resources. However, their electrochemical performance is limited by the larger ionic radius and severe volume expansion of Na⁺ ions. In this study, hollow yolk-shell structured iron sulfide (FeS) was encapsulated in graphitized carbon (H-C@FeS) to address these challenges. The material was synthesized using a solvothermal technique, followed by SiO₂ templating, carbon coating, and thermal treatment. The hollow structure buffered volume changes, while the carbon shell enhanced conductivity and structural stability. H-C@FeS exhibited excellent electrochemical performance, delivering 450 and 350 mAhg⁻¹ at 1.0 and 5.0 Ag⁻¹, respectively, with high-capacity retention. Moreover, the electrode maintained stable capacities of 600 mAhg⁻¹ at 60°C, indicating superior high-temperature stability. Electrochemical analyses, including CV, GITT, and in situ EIS with DRT interpretation, confirmed enhanced Na⁺ diffusion kinetics. The results suggest H-C@FeS as a promising high-performance and thermally stable anode for next-generation SIBs.

Natural wood is an excellent lightweight and renewable structural material, and recent studies have also demonstrated its potential as an electrode matrix for energy storage owing to its inherently porous structure. However, most existing wood-based electrochemical storage devices overlook the load-bearing capability of wood. In this work, we construct an all-wood-based structural supercapacitor, realizing the synergistic integration of wood as both a structural material and an energy storage device. The device is fabricated using delignified wood as a three-dimensional scaffold, with its pore walls uniformly coated with carbon nanotubes and poly(3,4-ethylenedioxythiophene) (PEDOT), thereby imparting both energy storage capability and electronic conductivity. Combined with a high-strength bicontinuous phase electrolyte, the result is an integrated structural supercapacitor with both excellent mechanical load-bearing performance and efficient energy storage capability. Benefiting from the intrinsic mechanical robustness of wood and the strength of the electrolyte, the supercapacitor demonstrates outstanding mechanical properties, including a bending modulus of up to 467.1 MPa and a bending strength of 14.1 MPa. Meanwhile, the well-preserved porous architecture of the wood matrix and uniform distribution of electroactive materials impart high electrochemical performance, achieving an areal specific capacitance of 112.0 mF cm⁻², a maximum energy density of 0.011 mWh cm⁻², and a maximum power density of 0.029 mW cm⁻². This all-wood-based supercapacitor not only broadens the application scope of wood but also provides a new strategy for structural-functional integration, enhanced energy storage efficiency, and sustainable material utilization.

Flexible, eco-friendly, wearable pressure sensors are crucial for human monitoring and smart home applications. Cellulose paper, a sustainable and flexible material, is promising for these applications but faces challenges, that is low sensitivity and poor durability. Inspired by cicada wings, the thin, yet resilient, papersheet was produced through commercially refining and wet-end upgrading (i.e., treating with alkyl ketene dimer and polyamide epoxy chloropropane), and the nano- and micro-scale of fibrillated cellulose fibers formed multi-level hierarchy branches, which significantly increased the paper's physical strength (tensile index of 84.2 kN·m/kg) and resilient properties (folding endurance over 1000 times). Taking advantage of the high strength paper, a sandwich structure of dual-layer paper sensor was assembled, that is the inner two pieces of ultra-thin insulation layer (5 g/m²), and the outer two sensing paper layers (30 g/m²) coated with Carboxylated Multi-Walled Carbon Nanotubes (MWCNT-COOH) as a conductive network. The resulting paper-based sensor exhibited excellent performance, such as ultra-wide detection range (0–4.13 MPa), ultra-high sensitivity (1.513 × 10⁵ kPa⁻¹ in the 0–16.5 kPa range), low detection limit (~8.1 Pa), rapid response/recovery times (44/21 ms), and excellent cyclic stability (over 12 000 cycles). It was successfully used to monitor pulse, respiration, voice, and joint motion, and could also be integrated into furniture such as floors, cushions, and mattresses for smart home and elderly care health monitoring. The humidity resistance (98% RH) and high-temperature tolerance (up to 80°C) further expand its application potential. In short, a reliable, cost-effective, and eco-friendly paper-based sensor was developed for wearable and smart home applications.

With rapid industrialization, municipal solid waste (MSW) production has increased, necessitating effective recycling solutions. However, material sorting and chemical post-treatment processes reduce user convenience and contribute to environmental pollution. To solve this problem, this study introduces a fully recycled, multi-material crumpled-ball triboelectric nanogenerator (FRMC-TENG). This device is composed entirely of recycled materials by applying a unique and effective crumpled ball design. Among fully recycled material-based TENGs, the FRMC-TENG showed excellent electrical performance by adopting an electrostatic discharge generation mechanism and exhibited a high peak current output of 1.76 A. Output performance was improved by using a multi-ball mixing structure, and the optimal structure was determined through various experiments. The effect of kitchen contaminants on the device was assessed. Even after exposure to contaminants, its electrical performance quickly recovered with a simple wipe. The FRMC-TENG can be fabricated in less than 1 min using recycled materials, lit up 1000 LEDs, and maintained the performance for over 30 min of hand operation. Its contamination resistance and diverse applicability suggest an effective and novel strategy for waste-to-energy.

Solar energy harvesting using photothermal nanofluids (NFs) depends greatly on how well light interacts with the suspended particles and how stable those particles remain in the base fluid. This work presents a geometrically engineered hierarchical design of hollow-core copper sulfide (H-Cu₂S) nanostructures (NSs) dispersed in ethylene glycol (EG) to enhance photothermal performance. The tailored shell morphology with hollow-core facilitates multiple light scattering and extended photon trapping, significantly enhancing solar absorption, particularly in the near-infrared region. This morphology-driven approach addresses limitations of conventional polymer or surfactant coatings, which, while improving colloidal stability, often compromise light accessibility and thermal conversion efficiency. The synthesized H-Cu₂S/EG NF demonstrated exceptional colloidal stability, negligible sedimentation, low viscosity enhancement, and robust thermal cycling, even at ultra-low loading of 0.01 wt%. Compared to 2D Cu₂S counterparts, this enhanced photon trapping, combined with the material's intrinsic semiconductor properties, yields an exceptional photothermal conversion efficiency of 86.8%, representing a 64.72% increase over EG as the base fluid. These features are achieved without the need for surface modification, benefiting from the intrinsically low density and optimized geometry of the NS. The resulting NFs exhibit significantly enhanced solar absorption and efficient light-to-heat conversion, establishing H-Cu₂S/EG NFs as promising candidates for next-generation solar thermal technologies.

COF@MXene composites are an emerging class of hybrid materials that integrate excellent electrical conductivity and chemical activity of MXenes with the structural tunability and porosity of covalent organic frameworks (COFs). This review outlines their synthesis strategies, structural features, and diverse applications in energy storage, environmental remediation, catalysis, and water treatment. The synergistic integration of COF@MXene enhances ion transport, active site exposure, and stability, enabling improved performance in lithium-sulfur batteries, supercapacitors, hydrogen production, and pollutant removal. These hybrids also offer promising design flexibility for tailored applications. Key challenges related to fabrication, scalability, and interface control are discussed, along with potential pathways for industrial adoption. COF@MXene composites represent a significant step forward in developing multifunctional materials for next-generation sustainable technologies.

Flexible pressure sensors hold transformative potential in personalized healthcare and motion-aware electronics. However, constrained by a single conduction mechanism, current sensors still face significant challenges in simultaneously achieving high sensitivity, wide range, and robust stability. Herein, a gradient doping hierarchical microstructure flexible piezoresistive sensor with multi-path conduction mechanisms is developed. The synergistic combination of micro-engineered surfaces and spatially graded doping enables significant resistance variation at low pressures, yielding a high sensitivity of 101.1 kPa⁻¹. Multi-path conduction mechanisms (including surface resistance, interlayer electrode resistance, interlayer contact resistance, interlayer tunneling resistance, and bulk resistance) enable tunable resistivity under high loads, extending the sensing range from 0.32 Pa to 3.6 MPa (a span of seven orders of magnitude). Moreover, the integrated full-carbon nanotubes/polydimethylsiloxane design shows high stability, durability (over 5000 cycles), and fast response/recovery time (10/58 ms). As a proof of concept, the sensor's application for broad-range biomechanical monitoring has been validated, spanning from subtle pulse waveform detection to high-intensity plantar pressure monitoring. This work advances next-generation wearables for simultaneous high-fidelity physiological tracking and extreme-force kinematic analysis.

Achieving efficient and stable formamidinium lead iodide (FAPbI₃) perovskite solar cells (PSCs) requires integrated control of crystallization kinetics and defect suppression. While ionic liquids (IL) have shown promise as multifunctional additives, their rational design remains challenging. Here, we develop an attention-focus graph neural network (GNN) framework that combines the molecular features of IL with device-level characteristics of FAPbI₃ PSCs. Our model identifies N-methyl-N-butylpyrrolidinium bis(trifluoromethylsulfonyl)imide ([MBPY][TFSI]) as an ideal dual-functional passivator. The [MBPY]⁺, acting as a Lewis base, passivates undercoordinated Pb²⁺ via Pb-N coordination bonds, whereas the [TFSI]⁻ anion mitigates interfacial defects via hydrogen bonding with FA⁺. It is found that the [MBPY]⁺ cation not only suppresses non-radiative recombination but also enhances the moisture resistance of the perovskite layer due to its hydrophobic alkyl chains. With the synergetic effect of [MBPY]⁺ and [TFSI]⁻ additives, the PSCs achieve a power conversion efficiency (PCE) of 25.03% with an open circuit voltage of 1.182 V, and retain 90.5% of their initial PCE after 1200 h storage at room temperature in air atmosphere (35% relative humidity). This work contributes to ongoing computational and experimental efforts in accelerating the exploration and prediction of potential ionic liquid passivation materials for perovskite solar cells.