Energy advances最新文献

Additions of calcium zincate (CaZn₂(OH)₆·2H₂O, CaZn) to zinc (Zn) anodes in alkaline batteries have been investigated and were found to remarkably increase cycle life at high 50% Zn utilization of the anode's theoretical capacity, thereby significantly reducing anode costs. A spectrum of anode formulations with increasing CaZn (0%, 30%, 70%, 100%) in mixtures with metallic Zn is investigated along with minor additions of Bi₂O₃, acetylene carbon black, and CTAB. The total molar zinc content is normalized; thus, electrode capacity is kept comparable, resulting in electrodes relevant to real world use cases. We report details of the cell design, electrolyte composition, electrode design, and cycle testing procedure, all of which are kept close to industrially relevant values. A pure CaZn anode with acetylene carbon was shown to achieve 1062 cycles at 20% Zn utilization in ZnO saturated 20 wt% KOH whereas traditional Zn anodes only utilize 10% for similar cycle life. At high 50% Zn utilization, CaZn anodes achieved ∼280 cycles while Zn anodes achieved ∼50 cycles, resulting in a five-fold improvement in cycle life resulting in approximately ∼25% reduction in cost per cycle. Scanning electron microscopy analysis of cycled electrodes shows that adding CaZn reduces electrode failure by slowing down formation of a passivating zinc oxide layer at the surface of the electrode as well as decreases shape change. This appears to occur because zinc and calcium remain intimately mixed forming CaZn, which reduces dissolution and reprecipitation, but slowly will segregate as inactive materials are pushed to the surface where conductivity is lower.

Engineering interfacial materials for use between the active layer and the electrodes in organic and perovskite solar cells is one of the most effective ways to increase device efficiency. Despite decades of development, new materials continue to emerge offering improved performance and streamlined fabrication of devices. Here, a hole transport layer (HTL) for organic and perovskite solar cells combining poly(styrene sulfonate) (PSS) and nickel (Ni²⁺) is presented. P-type carriers and p-doping at the anode are stabilized by the PSS backbone's negatively charged state. The impact of ionic moieties on the electronic band structure and characteristics of organic and perovskite solar cells must be understood. The combination of Nickel(II): poly(styrene sulfonate) (Ni:PSS) and poly(3,4-ethylenedioxythiophene): poly(styrene sulfonate) (PEDOT:PSS) can improve efficiency to 15.67% (perovskite solar cell) and 16.90% (organic solar cell) over traditional Ni:PSS and PEDOT:PSS. Ultraviolet photoelectron spectroscopic observations at HTL/donor interfaces indicate energy level alignment, which is the cause of various changes in device performance. Low ionization potential (IP) and hole injection barrier (ϕ_h) are essential at the HTL/donor interface for effective charge extraction in organic and perovskite solar cells.

CO₂ from adsorption with supported-amine sorbents using steam-assisted temperature-vacuum swing adsorption is a technology to capture CO₂ from the atmosphere (direct air capture). This process has many operational parameters and, on top of that, is heavily influenced by the ambient temperature and relative humidity. Identifying the minimum cost of direct air capture becomes a multi-dimensional problem in which climate conditions has to be incorporated as well. This study aims to evaluate the cost of direct air capture for year-round operation and to relate this to climate conditions. An optimization framework was developed with the ambient conditions as input parameters. This framework is able to find the minimum cost of direct air capture for a given fixed bed DAC facility and provides the corresponding operational parameters. These results were coupled to year-round weather data to find the total costs for continuous operation. We showed that the cost of CO₂ capture from air correlates well with the average annual temperature, with a high average temperature being more beneficial. Furthermore, climates with strong variation in weather conditions over the seasons require dynamic process control in order to operate at minimum cost of DAC. Overall, the presented optimization framework is an excellent tool to identify suitable locations for direct air capture and provide the operational parameters to minimize its cost.

Establishing a cost-effective and efficient electrocatalytic pathway for the hydrogen evolution reaction (HER) is the key to our quest for a carbon-neutral energy landscape. We report a simple and straightforward approach to synthesize an efficient, stable, and low-cost noble metal-free Bi₃O₄Br electrocatalyst. Tactical doping of Ni ions into Bi₃O₄Br effectively enhanced the conductivity, accelerated the charge transfer process, and provided more catalytic active sites to significantly boost the alkaline electrochemical HER performance of Bi₃O₄Br. This Ni-doped Bi₃O₄Br exhibited a lower overpotential of 662 mV compared to that of Bi₃O₄Br (736 mV) at a higher current density (50 mA cm⁻²). Additionally, the HER kinetics were also enhanced in terms of Tafel slope for this doped material (159 mV dec⁻¹) compared to the pristine Bi₃O₄Br (245 mV dec⁻¹), which coincides with a significant improvement in the mass activity (52 A g⁻¹ to 98 A g⁻¹). Notably, the overpotential of Ni-doped Bi₃O₄Br was further reduced to 614 mV at the same current density of 50 mA cm⁻² during photoelectrochemical HER performance testing, and the faradaic efficiency was improved from 79% to 87%. Finally, an enhanced durability of the material was observed for Bi₃O₄Br following the Ni-doping. Hence, this strategy highlights the importance of unravelling upgraded catalytic behaviour for abundant materials with rational doping.

The landscape of metal halide-perovskite solar cells (MH-PSCs) has witnessed significant progress in terms of efficiency over the past decade. Nevertheless, concerns over the toxicity of lead (Pb)-based perovskite structures have restrained their full market potential. In response, the exploration of Sn perovskites has emerged as a promising alternative, fueled by their narrow band gaps, superior carrier mobilities, low-temperature production, economic viability, and reduced hysteresis. These Sn perovskites exhibit competitive PCE while addressing the toxicity issues of Pb-based PSCs. This comprehensive review delves into the pivotal role of Sn in advancing PSCs, offering a consolidated understanding of its multifaceted applications. The report extensively examines the incorporation of Sn-based electron-transfer layers (ETLs) and absorber layers within PSCs, encompassing various dimensions, such as synthesis techniques, optoelectrical features, the future of Pb-free solar cells, integration into double PSCs, and the impact of doping strategies. Finally, this review proposes the future perspectives and investigations needed to make Sn-based PSCs a viable alternative to Pb-based MH-PSCs.

There are significant concerns about global warming and the energy crisis due to the rise in atmospheric carbon dioxide (CO₂) concentration and the depletion of fossil fuels. Converting CO₂ into organic molecules using the abundant solar energy would be a quick fix that would address both issues. Excess CO₂ is a major contributor to the greenhouse effect, which leads to global warming, extreme weather patterns, and a host of other environmental challenges. To tackle these problems, scientists are exploring novel approaches to adsorb CO₂, transform it into useful products, and then release it back into the atmosphere. Semiconductor materials play a crucial role in CO₂ reduction. Among these materials, zinc sulfide (ZnS) and doped ZnS have gained significant attention for the potential catalytic transformation of CO₂ into useful compounds. The semiconductor properties of ZnS and its derivatives make them particularly well-suited for this purpose. The present review provides a summary of the recent progress in the development of strategies for fabricating ZnS-based heterostructures with functional properties for CO₂ reduction. The mechanism of CO₂ conversion was also addressed with new insights into computational modelling. Lastly, future outlook on the development of catalytic ZnS-based materials for CO₂ reduction is provided.

The Ni-rich LiNi_xCo_yMn_1−x−yO₂ cathode (x ≥ 0.6) shows weak rate capability due to its deleterious surface lithium impurities and lattice defects. Herein, uniform ultrathin B₂O₃ coatings built by atomic layer deposition (ALD) are utilized to construct a B³⁺ doped single-crystal LiNi_0.83Co_0.12Mn_0.05O₂ (SC83) via post-annealing. LiOH is consumed due to reacting with B₂O₃ during the B₂O₃ ALD process, and then B₂O₃ is transformed into B³⁺ doping accompanied by the reduction of Li₂CO₃ during the post-annealing. Surface and bulk characterization results show that B³⁺ tends to diffuse into the bulk of the SC83 during the post-annealing, which expands the a and c axes and reduces the Li⁺/Ni²⁺ mixing of the SC83. When the B³⁺ content exceeds 0.54 wt%, B³⁺ segregation occurs on the surface of the SC83, which decreases the electronic conductivity of the SC83. B³⁺ doping at the content of 0.54 wt% gives the highest capacity of 177.6 mA h g⁻¹ at 1C rate. The B₂O₃ ALD coupled with post-annealing builds a highly electronic and Li⁺ conductive surface and bulk for the SC83, which is the key to the improvement of the rate capability.

Light harvesting and energy transfer are ubiquitous processes in natural photosynthesis, significantly advancing the widespread utilization of solar energy. In this study, we engineered a supramolecular light-harvesting system utilizing a pyridinium salt-modified cyanostilbene guest (CPy) and a water-soluble pillar[5]arene host (WP5). Through host–guest complexation between WP5 and CPy, the resultant supra-amphiphile further self-assembled into emissive nanoparticles within aqueous environments. Incorporating the commercially available dye DBT into these nanoparticles yielded an efficient artificial light-harvesting system with a high donor/acceptor ratio (>200). Additionally, this system demonstrated tunable fluorescence emission in the solid state and exhibited potential applications as a color-tunable fluorescent ink for information encryption. Our findings not only delineate a promising approach for fabricating efficient light-harvesting systems via a straightforward supramolecular strategy but also underscore the significant potential of tunable photoluminescent nanomaterials.

Narrow bandgap AgTaS₃ perovskite can offer highly efficient thin film solar cells (SCs) and become Si counterparts that are leading in the market. Herein, we study the response of a n-CdS/p-AgTaS₃/p⁺-Al_0.8Ga_0.2Sb device according to the variation of thickness, doping concentration, and defect densities in each layer using a solar cell capacitance simulator (SCAPS-1D). The optimized cell shows a V_OC of 0.78 V, PCE of 27.89% accompanied by a J_SC of 46.37 mA cm⁻², and a fill factor of 77.06%, paving the way for novel double heterojunction perovskite photovoltaic (PV) cells with remarkable performance.

Using sustainable energy-based electricity to synthesize NH₃ from H₂O and N₂ to release O₂ not only contributes to making chemical fertilizer production carbon neutral, but also holds promise for the use of NH₃ as a fuel. NH₃ synthesis from water and nitrogen was conducted at around 250 °C and below 1.0 MPa by combining a molten salt electrolyte of NaOH–KOH, a Pd alloy hydrogen-permeable membrane cathode, a Ni anode, and a Ru-based catalyst on the cathode backside. The rate and current efficiency for NH₃ formation were obtained as 11 nmol s⁻¹ cm⁻² (38 μmol h⁻¹ cm⁻²) and 25%, respectively, at 30 mA cm⁻², 1.0 MPa, and 250 °C. It was confirmed that the remaining percentage from the 100% current efficiency for NH₃ production was attributed to the current efficiency for H₂ production. The cell voltage was as low as 1.47 V at 30 mA cm⁻² and increased to 1.95 V at 100 mA cm⁻². The potential of this electrochemical system is discussed.