Energy advances最新文献

Hybrid supercapacitors (HSCs), incorporating the benefits of batteries and supercapacitors (SCs), have drawn significant research attention. In this regard, metal oxides and metal–organic frameworks (MOFs) have emerged as standout contenders for electrode materials because of their varying oxidation states, redox-active nature and immensely high porosity along with large active site ratios. Here, we fabricated praseodymium sesquioxide (Pr₂O₃) in combination with C₁₈H₆Cu₃O₁₂ MOF and compared their composites in different weight ratios. Through three-electrode characterizations, the composite with the same weight ratio revealed a remarkable specific capacity of 2046 C g⁻¹, showing enhanced performance because of the proper utilization of C₁₈H₆Cu₃O₁₂ porosity and the chemical activity of Pr₂O₃. This composite (Pr₂O₃/C₁₈H₆Cu₃O₁₂) was subsequently combined with activated carbon in a hybrid device, and numerous electrochemical characterizations were further performed. Based on the outcomes, the device demonstrated a maximum specific capacity of 310 C g⁻¹, along with energy and power densities of 67 W h kg⁻¹ and 6114 W kg⁻¹, respectively, and a capacity retention of 98%. After careful evaluation of the device, two different models were applied to estimate the approximate capacitive and diffusive contributions of the device. These findings highlight the potential of the study for future usage in battery-supercapacitor systems.

Waste Tagetes erecta (Marigold) yellow-coloured flowers comprising carbonaceous biomass and organic pigment carotenoids are utilised for enhanced solar hydrogen generation through water splitting. The carbonaceous moiety of floral biomass, acting as a substrate is oxidised, makes uphill water splitting thermodynamically easier and improves the hydrogen production rate. Carotenoid, having visible light absorption and charge separation capability, acts as a photosensitizer when hybridised with semiconductors. A carotenoid–CdS nanohybrid photocatalyst exhibits an enhanced photocatalytic activity of 15 mmol g⁻¹ h⁻¹, almost three times that of pristine CdS (5 mmol g⁻¹ h⁻¹), when tested for hydrogen generation via water splitting under the full-band solar spectrum. The activity is further enhanced to 35 mmol g⁻¹ h⁻¹ (∼7 times that of pristine CdS) when the Tagetes erecta–CdS photocatalytic system is used for water splitting. An AQE of ∼17% is achieved using 420 nm of visible light.

Electrolyte composition governs battery design due to its influence on ion dynamics, active material stability, and performance. Using electron paramagnetic resonance (EPR) and nuclear magnetic resonance (NMR), complemented by density functional theory calculations, the impact of electrolyte properties on an organic redox unit, TEMPO methacrylate (TMA), is explored. EPR hyperfine spectroscopy revealed that the amount of TMA bound to Li ions can be altered depending on the solvent used, and a higher fraction of TMA are Li-bound in linear carbonates compared to cyclic carbonates. The active material itself can be involved in the solvation shell of electrolyte ions, and insight into active material–electrolyte interactions from pulsed EPR may enable tuning of ion dynamics in organic radical batteries. Furthermore, the impact of moisture-dependent electrolyte degradation on the stability of TMA, investigated using time-resolved NMR and continuous wave EPR spectroscopy, resulted in the identification of degradation products and a degradation pathway mediated by the electrolyte.

Hydrogen is one of the most important feedstocks for the chemical industry, power production, and the decarbonization of other sectors that rely on natural gas. The production of hydrogen from plastics enables sustainable use of plastic waste and offers significant environmental benefits. Gasification emerges as a promising route for chemical recycling, converting plastic into hydrogen and other valuable chemicals. Although the gasification of plastic waste has recently gained attention, the number of studies regarding low-carbon hydrogen production is still limited. The effective integration of carbon capture, utilization, and storage (CCUS) is essential for achieving low-carbon hydrogen production via gasification, which enables the efficient capture and storage of CO₂ emissions. Incorporating coal waste and biomass into plastic gasification can synergistically enhance reforming reactions for hydrogen production, reduce tar content, and resolve feeding issues caused by plastic stickiness. Based on the previous studies, this paper briefly reviews the mechanisms of plastic gasification including plastic depolymerization, reforming, tar and char formation, and gasification; the discussions on feedstocks and effects of operating conditions on H₂ production including plastic-type, temperature, steam/carbon ratio, equivalence ratio, and catalysts; and the integration of CCUS and alternative recovery processes in plastic gasification for low-carbon hydrogen.

CsH₂PO₄ (CDP) is a well-known super-protonic conductor. However, it must operate under high humidity conditions to prevent dehydration and fast conductivity decay. Herein, we report that adding hydrophilic SnO₂ into CDP can suppress the rate of dehydration of CDP, thus stabilizing protonic conductivity over a broader range of water partial pressures (p_H2O). A total of seven compositions of (1 − x)CDP/(x)SnO₂ were prepared, where 5 ≤ x ≤ 40 (wt%), and examined for their phasal, microstructural, and vibrational properties using X-ray diffraction, field emission scanning electron microscopy, and Raman spectroscopy. The signature of H₂O retained in SnO₂-added CPD was confirmed by Fourier transform infrared (FTIR) spectroscopy. Among these samples, 18 wt% SnO₂ in CDP stood out, showing a stable protonic conductivity of 0.6 × 10⁻² S cm⁻¹ at 250 °C, even at 10% H₂O. We also provide data from pre- and post-test characterization to facilitate the understanding of the observed stability improvement and degradation mechanisms. Finally, we show stable H₂ pumping performance of electrochemical cells with pure CDP and 18 wt% SnO₂–CDP electrolyte and Pt/C electrode. Overall, 18 wt% SnO₂–CDP is the best composition, showing stable conductivity under reduced H₂O conditions and 18 wt% SnO₂–CDP electrolyte with Pt/C electrode is the best membrane electrode assembly (MEA) for electrochemical H₂ pumping for lower water partial pressure applications.

This study aims to explore the potential of citrus waste for valuable products. A special pyrolysis chamber was used to produce bio-oil through thermo-catalytic pyrolysis of sweet lemon (Citrus limetta) waste with a zeolite β, ammonium catalyst. The kinetic parameters were derived from thermogravimetric data using the Kissinger equation. The activation energy and frequency factor values for hemicellulose, cellulose, and lignin were determined to be 83.14, 108.08, and 124.71 kJ mol⁻¹ and 6.3 × 10⁴, 9.4 × 10⁶, 2.6 × 10⁹ min⁻¹, respectively. GC-MS analysis of the bio-oil revealed a variety of fuel-range hydrocarbons. Additionally, the biochar generated from non-catalytic and catalytic pyrolysis was compared, exhibiting different surface characteristics, as evident by scanning electron and transmission electron microscopy images. Our findings indicated that zeolite β, ammonium served as an effective catalyst by reducing the activation energy and lowering the temperature required for maximum degradation during pyrolysis, ultimately yielding a diverse array of useful products from citrus waste compared to the non-catalyzed reaction. Based on the fuel properties, it was concluded that the bio-oil, if slightly upgraded using the appropriate techniques, has a promising future as a green fuel.

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Graphite, with a modest specific capacity of 372 mA h g⁻¹, is a stable material for lithium-ion battery anodes. However, its capacity is inadequate to meet the growing power demands because the formation of an irregular solid electrolyte interphase (SEI) can result in unstable performance. In this research, we used a few cycles of atomic layer deposition (ALD) to deposit ZnO on graphite particles as an anode with improved electrochemical stability. Transmission electron microscopy revealed that ZnO was in the form of nanoparticles due to the inert surface properties of graphite and only a few cycles of ALD. Electrochemical characterization demonstrated that the ZnO ALD nanoparticles significantly inhibited dendrite growth, and X-ray photoelectron spectroscopy revealed that side reactions at the electrolyte–electrode interface were inhibited with the deposition of ZnO. The SEI layer was stabilized, which improved the cycling stability of the ZnO–graphite composite electrode. The electrode made of graphite with 2 cycles of ZnO ALD had about 20% higher discharge capacity than that of pristine graphite, and it remained stable at 420 mA h g⁻¹ after 500 cycles of charge/discharge. This surface modification technique can significantly increase the potential use of widely available graphite composites for high-performance batteries.

The desire to obtain higher energy densities in lithium–ion batteries (LIBs) to meet the growing demands of emerging technologies is faced with challenges related to poor capacity retention during cycling caused by structural and interfacial instability of the battery materials. Since the electrode–electrolyte interface plays a decisive role in achieving remarkable electrochemical performance, it must be suitably engineered to address the aforementioned issues. The development of coatings, particularly on the surface of cathode materials, has been proven to be effective in resolving interfacial issues in LIBs. The use of atomic layer deposition (ALD) over other surface coating techniques is advantageous in terms of coating uniformity, conformity, and thickness control. This review article provides a summary of the impact of various ALD-engineered surface coatings to the cycling performance of different intercalation cathode materials in LIBs. Since ALD allows coating development on complex substrates, this article provides a comprehensive discussion of coatings formed directly on a powder active material and composite electrode. Additionally, a perspective regarding the fundamental deposition parameters and electrochemical testing data to be reported in future research is provided.

In this study, we explored the efficacy of VO₂/carbon nanocomposites as promising photocatalysts for hydrogen generation and dye degradation under natural sunlight. These nanocomposites were synthesized using a facile one-step hydrothermal method at 180 °C using dextrose as the carbon source with optimized reaction time. The synthesized materials were characterized using X-ray diffraction (XRD), Raman spectroscopy, field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM) and X-ray photoelectron spectroscopy (XPS) analysis, to confirm their structural and physiochemical properties. FESEM analysis revealed the monoclinic crystalline structure of VO₂, accompanied by the formation of nanosheets surrounding carbon spheres of ∼50 nm in diameter. Optical analysis indicated that the material shows broad absorption in the visible region with a band gap range from 2.24 to 1.87 eV. XPS and Raman spectroscopy provided further confirmation of the successful formation of the VO₂/C composite. Among the synthesized samples, the VO₂/C composite synthesized within 48 hours of hydrothermal treatment (VC-5) exhibited the highest photocatalytic activity. The VC-5 composite exhibited a hydrogen production rate of 2545.24 μmol h⁻¹ g⁻¹ and demonstrated notable photocatalytic efficiency, achieving 97% degradation of methylene blue within 5 minutes and 80% degradation of Victoria blue within 15 minutes under natural sunlight. The enhanced photocatalytic performance of these hybrid nanomaterials is attributed to their large surface area, high porosity, uniform morphology, and the synergistic interaction between VO₂ and carbon. These factors enhance visible light absorption and charge carrier dynamics, significantly improving the photocatalytic performance of VO₂/C nanocomposites.