EcoMat最新文献

Lithium-sulfur batteries (LSBs) face several challenges, including the polysulfide shuttle effect and volume expansion. Binders are crucial in sulfur cathodes, maintaining the stability of electrode structures and mitigating volume changes. However, binders contribute no capacity, which makes it difficult to realize high-energy-density LSBs. Thus, it is necessary to reduce binder content and improve its utilization efficiency. This study introduces a natural plant Broussonetia papyrifera gum (BP)-derived binder with abundant polyphenols, polysaccharides, and proteins for the first time, not only minimizing the “dead weight” but also effectively capturing polysulfides and accelerating redox kinetics. Utilizing just 1 wt.% of the BP binder, the LSBs exhibit a remarkable initial discharge capacity of 980 mAh g⁻¹ and maintain at 568 mAh g⁻¹ after 500 cycles, demonstrating good cycling stability. Moreover, the BP-based sulfur cathode has also been successfully applied in pouch cells, delivering the initial and final capacities of 817 mAh g⁻¹ and 582 mAh g⁻¹ during 160 cycles. Highlighting the potential of natural polymers, this work bridges sustainable binder design and the commercial prospects of LSBs, charting an unconventional roadmap for their practical scale-up applications.

Electrochemical and photoelectrochemical hydrogen production are often pursued separately, even though both ultimately require electron consumption at the catalyst–electrolyte interface to form H₂. Integrating light harvesting, charge transport, and catalysis within a single photoelectrode can impose intrinsic trade-offs. Here, we propose a charge-decoupled electrode architecture that enables dual-mode electrochemical and photoelectrochemical hydrogen production by separating charge generation from charge consumption within one platform. Vertically aligned n-type GaN nanorods grown on silicon provide an electrically continuous pathway for charge transport and, under illumination, a source of photocarriers, while a continuous two-dimensional TiS₂ layer functions as an efficient interfacial charge transfer layer and the hydrogen-evolution-active interface. In electrochemical operation, externally supplied electrons are delivered through n-GaN and consumed at the TiS₂ surface to produce hydrogen at the working electrode. Under photoelectrochemical operation, photocarriers generated in n-GaN are separated at the TiS₂/n-GaN junction, and the electrode operates in photocathodic mode to drive proton reduction and hydrogen production at the illuminated working-electrode surface. These results demonstrate charge-decoupled functional switching and highlight its potential as an electrode-architecture principle for carbon-neutral hydrogen production across electrochemical and photoelectrochemical regimes.

Biophotovoltaic (BPV) systems use living photosynthetic organisms to generate electricity from sunlight, offering a clean and renewable energy source. Despite notable advances, further development toward practical applications remains limited by low current and power densities and insufficient system reusability. Here we report a hierarchical reduced graphene oxide (rGO) lattice electrode that was 3D printed and coated with polypyrrole (PPy) to serve as the BPV anode. The lattice geometry offers tunable porosity and high surface area to maximize BPV performance. PPy was electropolymerized onto the rGO framework via cyclic voltammetry, with the number of cycles optimized to achieve adequate PPy coverage, favorable cyanobacterial adhesion, and maximal photocurrent generation. The structural characteristics of the 3D printed lattice, particularly the number of voids, significantly influenced the photoresponse by modulating light penetration and mediator diffusion pathways. Two different BPV designs were tested using biofilm-coated electrodes and a suspension-based setup. The suspension-based BPV delivered a peak power density of 40 μW cm⁻² at 235 μA cm⁻². In a mediator-free operation, we measured up to 300 μA cm⁻² at a cyanobacterial loading of 25 μg mL⁻¹ chlorophyll a, and the reusability of the 3D PPy/rGO electrode was also demonstrated for seven consecutive days.

The present work reports the design of a novel nanocomposite adsorbent based on a bio-based PLA electrospun membrane doped with ZnO (28 wt% confirmed by TGA analysis) (ZnO@PLA) for removing different organic dyes (methyl orange [MO], congo red, and acid yellow 17) from wastewater. After characterizing the produced samples, batch tests were conducted to compare the removal capacities of pristine PLA and ZnO@PLA. MO was chosen to assess the effect of temperature (25°C–80°C), contact time (0–24 h), pH (3–9), initial dye concentration (25–200 ppm), salinity (0–100 000 ppm), and adsorbent dosage (0.5–3 g/L). The Langmuir model best fits the adsorption data, providing a q_m = 94.07 mg/g. Thermodynamic calculations demonstrate the spontaneity of the MO removal process and its favorability at low temperatures due to the negative value of enthalpy. Kinetic modeling suggests an excellent fit with the PSO model. Furthermore, the design of experiments (DoEs) method was applied to forecast the removal (%) of MO through a polynomial model by modifying the temperature, pH, and initial MO concentration, confirming that both elevated temperature and higher dye concentrations slightly suppress the adsorption recovery. Finally, an adsorption mechanism was proposed based on interactions of MO with the ZnO-modified electrospun adsorbent.

Sustainable lignin valorization through solar energy conversion remains challenging due to the inherent resistance of lignin in photoelectrochemical (PEC) oxidations. Herein, an integrated PEC system combining metal phthalocyanine catalysts with organic semiconductors is presented to achieve direct Kraft lignin oxidation with an unprecedented production rate and stability. An optimized Ni-Co phthalocyanine/organic-semiconductor photoanode achieves a photocurrent density of 13.4 mA cm⁻² and maintains stable operation for 28 h, representing the highest performance reported for direct lignin oxidation. This system efficiently suppresses the oxygen evolution reaction, directing 80.6% of the total current toward lignin oxidation. Reaction environment modulation allows precise control of the reaction pathway, with a vanillic acid production ratio reaching 76.1% and a production rate of 7.43 μmol cm⁻² h⁻¹ under 1 M NaOH. Density functional theory calculations clarify that lignin preferentially adsorbs parallel to the phthalocyanine surface, forming π–π interactions that facilitate β-O-4 bond cleavage, the key step for generating valuable aromatic monomers. Furthermore, the central metal tuning modulates the energy barrier with cobalt-centered phthalocyanines exhibiting the lowest barrier and highest activity. These insights provide a molecular-level design principle to overcome the resistance of lignin and establish a cornerstone for sustainable lignocellulosic biomass upcycling.

MXene-based heterogeneous structures have attracted considerable attention due to their outstanding multifunctional performance in smart electronic and thermal management. In this work, 2D/0D/2D Ti₃C₂T_x MXene/Ag@g-C₃N₄ composite films were fabricated by introducing 0D/2D Ag@g-C₃N₄ nanosheets into the Ti₃C₂T_x matrix, forming a layered architecture featuring Ag-mediated interfacial networks. The Ag nanoparticles function as conductive bridges between g-C₃N₄ and Ti₃C₂T_x nanosheets, generating a heterogeneous structure enriched with abundant interfacial regions and strong interlayer interactions. The resulting heterogeneous films exhibit exceptional electromagnetic interference (EMI) shielding effectiveness of 51.4 dB and high absolute shielding effectiveness of 25 855 dB cm² g⁻¹. This superior EMI shielding performance stems from pronounced electromagnetic wave reflection, combined with enhanced absorption arising from local dipolar polarization, porous microstructures, and extensive interface interactions. In addition, the Ti₃C₂T_x MXene/Ag@g-C₃N₄ films demonstrate robust thermal-management capability, delivering significant infrared stealth performance (radiative temperature reduction of 137.3°C at 200°C) alongside rapid electrothermal heating to 211°C at 3.0 V. Overall, this Ag-assisted heterogeneous assembly strategy provides a versatile pathway for engineering multifunctional MXene-based composites that integrate EMI shielding with advanced thermal management functionalities.

Scalable and lower-severity synthesis of Na₃V₂(PO₄)₃/C (NVP/C) cathodes for sodium-ion batteries (SIBs) remains limited by trial-and-error optimization of hydrothermal processing conditions. This practice is known to cause variations in crystal quality and poor reproducibility in electrochemical behavior. Microwave-assisted hydrothermal synthesis has emerged as a faster and more efficient route, but the combined effects of synthesis temperature (T) and holding time (t) on phase evolution and electrochemical performance of NVP remain insufficiently understood from a statistical perspective. In this study, central composite design coupled with response surface methodology (CCD-RSM) is used to systematically examine the T–t parameter space for NVP/C synthesis. The statistically identified optimum at 140°C for 20 min produces a mixed granular-porous morphology encased in a semi-graphitic carbon shell (~4.22 nm), achieved without dopants or conductive additives, at substantially lower thermal severity (140°C/20 min vs. 180°C–200°C/12–24 h for conventional hydrothermal routes). The optimized NVP (M-140-20✶) delivers 105.65 mAh g⁻¹ at 0.1C, retains 99.7% capacity after 100cycles at 1C, and sustains 85.4% retention after 3500 cycles at 3C, competitive with chemically modified NVP systems requiring significantly higher synthesis energy. The NVP‖HC full cell achieves approximately 311 Wh kg⁻¹ at 0.5C, while retaining a high energy efficiency of 93.7% at 1C. Kinetic analysis reveals mixed Na⁺ storage, with b-values of 0.62–0.67 and increasing surface contribution at higher scan rates, while post-mortem XRD, SEM, and HR-TEM show degradation through micro-cracking, carbon-shell thinning, and separator-fiber intrusion. These findings clarify synthesis-structure-performance-degradation relationships in polyanionic cathodes.

The rising atmospheric CO₂ concentration has intensified interest in technologies that couple carbon utilization with the production of high-value functional materials. Direct conversion of captured CO₂ into carbon architectures offers a distinct route in which emissions are transformed into electrochemically active solids rather than molecular fuels or commodity chemicals. Unlike conventional carbons, CO₂-derived carbons are generated through thermochemical, electrochemical, plasma-assisted, and hybrid conversion pathways that reconstruct carbon frameworks from fully oxidized molecular feedstocks. These synthesis routes enable hierarchical porosity, tunable graphitic order, high defect densities, and heteroatom-coordinated active sites, providing opportunities to engineer electronic structure and interfacial reactivity across multiple length scales. This review examines how synthesis conditions govern structural evolution and how these features dictate performance in electrocatalytic and electrochemical energy-storage systems. Emphasis is placed on defect-mediated active sites, heteroatom coordination, interfacial charge redistribution, and metal–carbon interactions that control oxygen reduction, oxygen evolution, and hydrogen evolution reactions. The roles of CO₂-derived carbons in lithium-ion, sodium-ion, lithium–sulfur, and related battery chemistries, as well as electrochemical capacitors, are evaluated through their influence on ion transport, charge-transfer kinetics, and storage mechanisms. Recent advances reveal that CO₂ conversion can encode functionality directly during synthesis, eliminating many post-synthetic modification steps. However, significant barriers remain, including scalable manufacturing, deterministic defect control, long-term stability, and rigorous environmental and economic assessment. Future progress will depend on integrating operando characterization, theory-guided design, machine learning, and life-cycle analysis to establish predictive design rules and accelerate deployment in sustainable energy technologies.

Rational electrode structure design is a key to bridging electrochemical energy storage and capacitive deionization devices. However, electrode materials are often limited by sluggish ion transport, low utilization of electroactive sites, and unstable integration between redox-active phases and conductive frameworks. Here, we developed a proton-coupled self-templating hollowing-growth strategy to construct hierarchical core-shell arrays of hollow carbon nanotubes (CNTs) and conformal MnO₂ nanosheets (CMT). Proton-induced etching of zinc oxide (ZnO) nanowires was coupled with concurrent deposition of redox-active MnO₂, yielding a hierarchical hollow architecture with conductive carbon backbones, hollow ion-transport conduits, and accessible MnO₂ nanosheets. This integrated structure accelerates charge transfer, facilitates electrolyte penetration, and improves electroactive site utilization. As a result, the optimized CMT-40 electrode delivers an areal capacitance of 0.52 F cm⁻² at 2 mV s⁻¹ and retains 0.25 F cm⁻² at 100 mV s⁻¹. When assembled into a flexible asymmetric supercapacitor, the device delivered a maximum volumetric energy density of 2.85 mWh cm⁻³ at 25.5 mW cm⁻³ and retained ~1.8 mWh cm⁻³ at a high power density of 453.8 mW cm⁻³. In capacitive deionization (CDI), the same architecture enables fast ion electrosorption and a salt adsorption capacity of 132.2 mg g⁻¹ at 1000 ppm sodium chloride (NaCl) solution, together with good cycling stability. This work provides an effective framework for designing multifunctional hollow electrodes for integrated high-rate energy storage and electrochemical desalination.

Primary lithium (Li) metal batteries are widely used but are typically discarded after single-use operation, resulting in a dispersed and underutilized Li-containing waste stream. Here, we report an integrated electrochemical–chemical pathway for Li recovery from spent primary Li metal batteries. Residual Li is first reactivated through controlled electrochemical rejuvenation, inducing Li redeposition onto the anode-side casing. The regenerated Li is then selectively extracted and stabilized at the molecular level using a polycyclic aromatic hydrocarbon (PAH)–ether solution, followed by antisolvent-induced precipitation and moderate thermal conversion to lithium carbonate (Li₂CO₃). The effects of processing parameters, including drying atmosphere and calcination temperature, on phase evolution and Li content are systematically examined. The recovered Li₂CO₃ exhibits high crystallinity and Li purity, as further validated by the synthesis and electrochemical evaluation of lithium cobalt oxide (LiCoO₂) cathodes. The resulting cathode materials demonstrate crystallographic integrity and electrochemical performance comparable to those derived from commercial Li sources. By coupling electrochemical control, solution-phase Li leaching, and materials regeneration, this work establishes a process-oriented framework for valorizing Li from primary battery waste and demonstrates a closed-loop Li utilization pathway that bridges recovery and functional material regeneration, highlighting an underexplored opportunity for sustainable Li resource recovery.