Energy advances最新文献

High-efficiency solar cell architectures, including silicon heterojunction (SHJ) and perovskite/silicon tandems, rely heavily on the unique properties of transparent conducting oxides (TCOs). The push towards terawatt-scale PV manufacturing means it is increasingly desirable to develop indium-free TCOs to facilitate the upscaled manufacturing of high-efficiency cell designs. Aluminium-doped ZnO (AZO) deposited by atomic layer deposition (ALD) has emerged as a promising candidate due to its combination of optical transparency and electrical conductivity. In addition, AZO has also been shown to passivate the c-Si surface. The ability for one material to provide all three properties without requiring any indium is advantageous in single junction and tandem solar devices. Herein, we demonstrate exceptional silicon surface passivation using AZO/AlO _x stacks deposited with ALD, with a J ₀ < 1 fA cm^-2 and corresponding implied open circuit voltage (iV_OC) of 740 mV. We provide a comprehensive analysis of the role of ALD precursor dosing to achieve optimised performance. A broad range of characterisation approaches were used to probe the structural, compositional, and chemical properties of AZO films. These indicated that the passivation properties are governed by a delicate interplay between the Zn and Al concentrations in the film, highlighting the importance of precise process control. Optical modelling in a single junction SHJ architecture indicates these AZO films are close in performance to high-mobility indium-containing TCOs. The insights provided by this work may help to further the case of indium-free TCOs, which is critical for upscaled production of high-efficiency solar cells.

A graphical abstract is available for this content

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.

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.

The annealing conditions of the layer-exchange synthesis of multilayer graphene significantly affected its crystallinity and lithium-ion battery anode properties. We demonstrated excellent capacity retention and fast charge–discharge properties in multilayer graphene synthesized at low temperatures (400 °C). These results could contribute to the realization of flexible thin-film batteries.

Lithium-ion batteries (LIBs) are essential for energising portable devices, electric cars, and energy storage systems. Graphite is a frequently utilised anode material; nonetheless, the continual formation of a solid electrolyte interface (SEI) during cycling results in capacity degradation owing to electrolyte depletion. This study tackles this issue by employing alumina coatings on graphite electrodes via the spray coating technique, which is cost-effective and scalable. Electrodes with different alumina concentrations (1 wt%, 4 wt%, and 7 wt%) were assessed for electrochemical performance. The 1 wt% alumina-coated electrode demonstrated enhanced cycling stability, with 94.97% capacity retention after 100 cycles, in contrast to 91.74% for the uncoated graphite. The Al₂O₃ coating functions as a preformed SEI, diminishing electrolyte decomposition and improving the cycling performance and rate capability of electrodes, particularly at elevated C-rates. This research illustrates that using spray-coated alumina is an effective technique for enhancing the durability and performance of graphite anodes in lithium-ion batteries, with the potential for extensive applications in energy storage systems.

Green hydrogen production has been a particular focus in recent times for implementing sustainable fuels in the future energy economy. One of the most effective ways to produce clean and green hydrogen is electrocatalytic overall water splitting. Various researchers with their persistent explorations have made this topic, the research hotspot in understanding the catalysis mechanism and developing new novel materials. As the hydrogen evolution reaction (HER) kinetically limits the overall water splitting reaction, this work demonstrates the L-cysteine assisted synthesis of millerite nickel sulfide dispersed as particles on nickel foam (NS/NF) by a simple one-step hydrothermal process as a self-supported working electrode. The controlled phase of NiS is confirmed by XRD and TEM analysis and the size and morphology of the catalyst are characterised by SEM analysis. XAS analysis further explores the bulk structure and chemical coordination within the crystal system according to the XANES and EXAFS findings. The HER performance of the NS/NF catalyst exhibits superior activity to bare NF, requiring an overpotential of 140 mV to deliver a current density of −10 mA cm⁻² with a Tafel slope of 112.3 mV dec⁻¹. The catalyst demonstrated excellent durability for 50 h with further electro-activation of NS/NF under reduction conditions. In a two-electrode system, NS/NF||RuO₂ required only 1.79 V as the overall cell voltage to generate a current density of 10 mA cm⁻². This study illustrates a simple and facile route for NiS synthesis with extendable electrochemical surface area (ECSA), demonstrating superior HER activity over time, under alkaline conditions.

Composite solid-state electrolytes (CSEs) with multiple phases offer greater flexibility to customize and combine the advantages of single-phase electrolytes, making them promising candidates for commercial all-solid-state batteries (ASSBs). Based on existing investigations, this review provides a comprehensive overview of the recent progress in CSEs. First, we introduce the historical development of solid-state ionic conductors, and then summarize the fundamentals including key materials and mechanisms of lithium-ion transport. Three main types of advanced structures for CSEs are classified and highlighted according to the recent progress, namely composite solid electrolytes with passive fillers, composite solid electrolytes with active fillers, and 3D framework composite solid electrolytes. Finally, the challenges and perspectives of the composite solid-state electrolytes are discussed.

Hydrogen is emerging as an immense source of energy having the potential to at least partly replace fossil fuels. It is an abundant element on earth, but does not mainly exist in free form. Hydrogen can be produced through different technologies and feedstocks, and based on these, it can be categorized into colors with different environmental impacts. This work aimed to review the environmental impacts of the production of gray (from natural gas without carbon capture and storage), brown (from coal gasification), blue (from fossil fuels with carbon capture and storage), green (from renewable energy or biological process), and turquoise (pyrolysis of natural gas) hydrogen and to identify sustainable hydrogen production pathways that minimize environmental impacts. Global warming, acidification, eutrophication, and resource depletion were considered as indicators to assess the environmental impacts. The results showed that brown hydrogen produced via coal gasification had the highest global warming, acidification, and resource depletion impacts among all the options considered. On the other hand, green hydrogen from electrolysis through wind energy had the lowest environmental impacts. However, adopting these hydrogen colors presents different challenges and opportunities. Success depends on effective policy frameworks, international cooperation, and technological readiness to ensure positive contributions to global sustainability goals.

Redox flow batteries (RFBs) fulfill the requirements for long-duration energy storage (LDES), and the use of bromine as a catholyte has garnered substantial interest due to its high availability and low cost. However, at high states of charge, the vapor pressure of bromine presents significant safety concerns within the catholyte tank, while polybromide species have been shown to corrode the metals present in the stack. Traditionally, soluble bromine complexing agents (BCAs) have been employed to mitigate the concentration of free bromine, providing some improvement in safety; however, this has often resulted in significant reductions in power density and durability. In this study, we present the development of a solid BCA incorporated into the catholyte tank of a hydrogen-bromine RFB (HBRFB). The long-term separation of the bromine-rich solid phase from the flowing liquid phases enables sustained high performance for over 250 cycles. The effective complexing-dissociating equilibrium within the electrolyte tank ensures adequate bromine concentration for operation at high current densities. This advancement significantly enhances the viability of bromine-based RFB technology as a dependable solution for long-duration energy storage.