Energy advances最新文献

The synthesis and physicochemical and electrochemical properties of several fluorine-free ionic liquids (ILs) comprising dialkylphosphate anions coupled to N-heterocyclic cations such as pyrrolidinium (Pyrr), piperidinium (Pip), and pyridinium (Py) are presented. All the ILs are synthesized in a single step by reacting trialkyl phosphates with pyrrolidine, piperidine, or pyridine. These ILs exhibit ionic conductivities in the range of 0.07 to 0.57 mS cm⁻¹ at 20 °C, while increasing to 3.98 mS cm⁻¹ at 60 °C, and an electrochemical stability window (ESW) up to 6.8 V on a glassy carbon (GC) electrode. Furthermore, a comparative performance of symmetric supercapacitors (SCs) made of multiwalled carbon nanotubes (MWCNTs) using [EMPyrr][DEP] and [BMPyrr][DBP] as electrolytes is presented. The SC based on [EMPyrr][DEP] reveals higher capacity retention, a power density of 1050 W kg⁻¹, and an energy density of 68 Wh kg⁻¹ using 0.5 A g⁻¹ at 60 °C. This paves the way for developing fluorine-free and high-performant IL-based electrolytes for supercapacitors operating at elevated temperatures.

This research explores the photovoltaic performance of four different perovskite solar cell (PSC) architectures, with emphasis on how material selection, absorber layer thickness, defect and acceptor densities, interface imperfections, and temperature fluctuations influence device efficiency. Energy band alignment analyses were conducted to enhance charge separation and extraction. Among the configurations, the device incorporating dual absorbers Sr₃PBr₃ and Ca₃AsI₃ exhibited the highest efficiency. Analysis of absorber thickness effects indicated maximum power conversion efficiencies (PCEs) of 20.71% for device-i (FTO/CdS/Sr₃PBr₃/Au) and 19.75% for device-ii (FTO/CdS/Ca₃AsI₃/Au) at a thickness of 1.0 μm. In contrast, device-iv (FTO/CdS/Ca₃AsI₃/Sr₃PBr₃/MoO₃/Au), which employed both a dual-absorber design and a MoO₃ hole transport layer (HTL), achieved an optimal PCE of 29.77% with each absorber layer also at 1.0 μm thickness. The investigation into defect densities revealed that increased defect levels significantly diminished performance. Device-iv stood out for its enhanced stability and efficiency, resulting from fine-tuned acceptor density and effective interface defect mitigation. Temperature analysis showed a general decline in efficiency with increasing temperature, though device-iv maintained relatively higher thermal stability. Overall, the study highlights the critical role of dual absorber layers, optimized geometries, effective HTLs, and minimized defect concentrations in advancing the efficiency and durability of high-performance PSCs.

Inverted perovskite solar cells, known for their low temperature processability and reduced hysteresis, benefit from the use of nickel oxide (NiO_x) as a hole transport material, which enhances stability. The doping of NiO_x with lithium improves its electrical properties by creating Ni³⁺ sites through intrinsic doping with Ni vacancies. This study investigated the impact of Li doping on the optical and electrical properties of NiO_x and evaluated the optimal doping concentration for solar cell performance. Additionally, the diffusion of small sized Li-ions from the NiO_x hole transport layer into the photoactive perovskite layer was investigated, which led to an improvement of the perovskite absorber quality through defect passivation caused by lithium diffusion from the NiO_x layer, enhancing device performance. The incorporation of lithium significantly boosted all solar cell parameters, leading to a 60.8% increase in power conversion efficiency (PCE), from approximately 12% to a maximum of 19.3%.

Thin, fast-conducting and mechanically robust separators are expected to be advantageous in enabling all-solid-state batteries with high energy densities and good electrochemical performance. In this study, a potentially new scalable fabrication route for flexible thiophosphate–polymer separator membranes is demonstrated. By infiltrating a commercially available polymer mesh with the highly conductive inorganic solid ion conductor Li_5.5PS_4.5Cl_1.5, a hybrid separator membrane with a high ionic conductivity is realized. The electrochemical evaluation via rate capability tests reveals superior performance at low stack pressures and high C-rates, when comparing cells employing the hybrid membrane separator, to cells utilizing conventional solid electrolyte separators. As a proof of concept, a full cell implementing the hybrid membrane between a Si-based anode and a LiNi_0.83Co_0.11Mn_0.06O₂–Li_5.5PS_4.5Cl_1.5 composite cathode is evaluated. The experimental work is complemented by resistor network modelling of the hybrid membrane sheets, shedding light on potential challenges in cell operation.

This study presents molecular boron subphthalocyanine complex precursors ((Cl-B-SubPc) 1 and (Cl-B-SubPc-OC₁₂H₂₃) 2) designed for efficient CO₂ reduction. The resulting heterogeneous catalysts exhibit remarkable total faradaic efficiencies of up to 98%, integrated into practical cell assemblies. Optimizations encompass not only catalyst design but also operational conditions, facilitating prolonged CO₂ electrolysis across various current densities. Varied C₁-, C₂-, and C₃-product yields are observed at different reductive potentials, with electrocatalysis experiments conducted up to 200 mA cm⁻². Comparative electrochemical analyses across H-cell and zero-gap cell electrolyzers show the potential for industrial scale-up. Mechanistic elucidation via in situ UV-vis spectroelectrochemistry, DFT calculations, and ESR spectroscopy demonstrates the involvement of boron N–C sites, initiating radical formation and utilizing boron's Lewis acid behavior in CO₂ capture, followed by proton-coupled electron transfer. Overall, the study underscores the transformative potential of boron subphthalocyanine systems in advancing CO₂ utilization technologies.

Graphene and other conductive substrates have been used to improve the electrochemical efficiency of monolayer VS₂, establishing it as a potential anode material for LIBs. Nonetheless, a detailed understanding of the synergistic relationship between VS₂ and graphene (Gr), which is fundamental for boosting Li⁺/Na⁺ electrochemical storage device performance, remains limited. This study utilized density functional theory (DFT) computations to systematically analyze the VS₂/Gr composite as an optimized electrode for Li⁺/Na⁺ electrochemical storage devices. Our findings reveal that VS₂/Gr possesses outstanding structural stability, remarkable mechanical stiffness, strong ion adsorption ability, and enhanced charge transfer efficiency. Additionally, it exhibits a high theoretical storage capacity, a shallow average open-circuit voltage, and low ion diffusion barriers. The diffusion barriers of 0.11 eV for Li and 0.16 eV for Na are lower than those of widely studied composite materials, enabling an exceptionally fast Li⁺/Na⁺ diffusion rate during charge/discharge processes. The predicted open-circuit voltages for Li⁺/Na⁺ are 0.75 V and 0.77 V, respectively, with corresponding theoretical storage capacities reaching 1156 mAh g⁻¹ for Li and 770 mAh g⁻¹ for Na. These findings offer key insights for the experimental design and optimization of VS₂/Gr anodes, paving the way for ultra-fast charging and high-capacity Li⁺/Na⁺ electrochemical storage devices.

The rapid developments in portable electronic devices, electric vehicles, and smart grids are driving the need for high-energy (>500 Wh kg⁻¹) rechargeable batteries. Lithium–sulfur batteries (Li–S) are of interest due to their high theoretical energy density (2600 Wh kg⁻¹ or 2800 Wh L⁻¹), but their commercialisation is restricted by several technical challenges, including the use of a highly reactive lithium metal anode. Using Li₂S as the cathode to couple with Li-free anodes, such as Si and intermetallic alloys, presents a realistic approach to avoiding the safety issues associated with metallic lithium. However, the low electrochemical activity of Li₂S and the shuttling effect of lithium polysulfides (LiPS) prevent the realization of high capacity and good cyclic performance. The usual Li₂S/carbon (C) composite cathode suffers gradual capacity fading over long-term cycling due to irreversible LiPS migration in lithium–sulfur batteries. Although the presence of C in the cathode composite provides a conductive path to utilize the active material, the irreversible migration of LiPS still exists. In this work, we introduce a polar SnS₂ additive in the cathode composite (Li₂S/C) via a highly scalable ball milling method to adsorb LiPS. The Li₂S/C/SnS₂ composite acts as a restriction for LiPS by chemisorption and provides a physical barrier to LiPS shuttling. We have synthesized three types of cathode composites with different weight percentages of C and SnS₂ while keeping the amount of Li₂S constant and studied their electrochemical performance in characteristic cells. We found that the Li₂S/C (20%)/SnS₂ (5%) composite shows a high initial capacity of 711 mAh g⁻¹ at 0.1C and retains a capacity of around 400 mAh g⁻¹ after 100 cycles. In comparison, the Li₂S/C (25%) composite delivered a capacity that was 100 mAh g⁻¹ less than that of the Li₂S/C (20%)/SnS₂ (5%) composite after 100 cycles. The approach and design presented in this work could lead to the development of effective shuttle suppression material additives for future Li–S batteries.

As the basis for many functions of the battery management system (BMS) such as state estimation and thermal runaway warning, stable sampling data are crucial for the safe operation of electric vehicles (EVs). In this paper, a sampling fault diagnosis method for power battery data in cloud platforms is proposed based on a residual network (ResNet) and bi-directional long short-term memory (BiLSTM) neural network, which can effectively identify the abnormalities of the battery sampling data and recognize the failure modes. Firstly, through the analysis of fault data and sampling circuits for real EVs, four typical failure modes are selected to complete the fault injection experiments. The physical simulation model of the fault circuit is established, and the corresponding mathematical empirical model is condensed. Then, based on the understanding of the abnormal data distribution pattern, the fault diagnosis algorithms based on a threshold and the ResNet–BiLSTM neural network are developed, respectively. Finally, the algorithms are introduced into the simulation dataset and real-vehicle dataset for testing. The results show that both algorithms have high effectiveness and accuracy, with the latter exhibiting strong fault diagnosis capability. In summary, the proposed sampling fault diagnosis method is feasible and provides a theoretical basis for future multi-type fault diagnosis of BMSs.

Biofuels are pivotal in transitioning to sustainable energy systems, offering renewable alternatives to fossil fuels with reduced emissions. This review examines the evolution of biofuel production, contrasting first-generation biofuels derived from food crops with second-generation biofuels from non-food lignocellulosic feedstock. This review evaluates social and environmental impacts, with a focus on land use, energy efficiency, and scalability. Advances in synthetic biology and metabolic engineering have revolutionized biofuel production by optimizing microorganisms like bacteria, yeast, and algae for enhanced substrate processing and industrial resilience. Key enzymes, such as cellulases, hemicellulases, and ligninases, facilitate the conversion of lignocellulosic biomass into fermentable sugars. CRISPR-Cas systems enable precise genome editing, while de novo pathway engineering produces advanced biofuels such as butanol, isoprenoids, and jet fuel analogs, boasting superior energy density and compatibility with existing infrastructure. Notable achievements include 91% biodiesel conversion efficiency from lipids and a 3-fold butanol yield increase in engineered Clostridium spp., alongside ∼85% xylose-to-ethanol conversion in S. cerevisiae. However, commercial scalability is hindered by biomass recalcitrance, limited yields, and economic challenges. Emerging strategies, including consolidated bioprocessing, adaptive laboratory evolution, and AI-driven strain optimization, address these barriers. This review also explores biofuel integration within circular economy frameworks, emphasizing waste recycling and carbon-neutral operations. Multidisciplinary research is essential to enhance economic viability and environmental sustainability, ensuring biofuels play a central role in global renewable energy systems.

We present a detailed first-principles study of the electrical and thermal transport, and the thermoelectric figure of merit zT, of the oxide perovskite SrTiO₃ in the orthorhombic Pnma, tetragonal I4/mcm and cubic Pmm phases. Analysis of the lattice thermal conductivity shows that the “particle-like” contribution, κ_p, is highest in the Pmm phase due to larger phonon group velocities. We also find that all three phases show significant heat transport through glass-like interband tunnelling. On the other hand, we predict the cubic and orthorhombic phases to show superior n-type conductivity, due to significantly stronger polar-optic phonon scattering and shorter electron lifetimes in the tetragonal phase. Due to its superior electrical properties, we predict that the Pmm phase will attain a 25% larger high-temperature zT than the I4/mcm phase, while we predict the best zT can be obtained for the Pnma phase due to its favourable electrical properties and low κ_latt. This work provides new insight into the impact of structure type on the thermoelectric performance of oxide perovskites, and indicates targeting particular structure types, e.g. through chemical doping, could provide a facile route to optimising the zT of SrTiO₃ and related systems.