Energy & Environmental Materials最新文献

Direct synthesis of layer-tunable and transfer-free graphene on technologically important substrates is highly valued for various electronics and device applications. State of the art in the field is currently a two-step process: a high-quality graphene layer synthesis on metal substrate through chemical vapor deposition (CVD) followed by delicate layer transfer onto device-relevant substrates. Here, we report a novel synthesis approach combining ion implantation for a precise graphene layer control and dual-metal smart Janus substrate for a diffusion-limiting graphene formation to directly synthesize large area, high quality, and layer-tunable graphene films on arbitrary substrates without the post-synthesis layer transfer process. Carbon (C) ion implantation was performed on Cu–Ni film deposited on a variety of device-relevant substrates. A well-controlled number of layers of graphene, primarily monolayer and bilayer, is precisely controlled by the equivalent fluence of the implanted C-atoms (1 monolayer ~4 × 10¹⁵ C-atoms/cm²). Upon thermal annealing to promote Cu-Ni alloying, the pre-implanted C-atoms in the Ni layer are pushed toward the Ni/substrate interface by the top Cu layer due to the poor C-solubility in Cu. As a result, the expelled C-atoms precipitate into a graphene structure at the interface facilitated by the Cu-like alloy catalysis. After removing the alloyed Cu-like surface layer, the layer-tunable graphene on the desired substrate is directly realized. The layer-selectivity, high quality, and uniformity of the graphene films are not only confirmed with detailed characterizations using a suite of surface analysis techniques but more importantly are successfully demonstrated by the excellent properties and performance of several devices directly fabricated from these graphene films. Molecular dynamics (MD) simulations using the reactive force field (ReaxFF) were performed to elucidate the graphene formation mechanisms in this novel synthesis approach. With the wide use of ion implantation technology in the microelectronics industry, this novel graphene synthesis approach with precise layer-tunability and transfer-free processing has the promise to advance efficient graphene-device manufacturing and expedite their versatile applications in many fields.

Single-atom catalysts (SACs) have received significant interest for optimizing metal atom utilization and superior catalytic performance in hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and oxygen reduction reaction (ORR). In this study, we investigate a range of single-transition metal (STM₁ = Sc₁, Ti₁, V₁, Cr₁, Mn₁, Fe₁, Co₁, Ni₁, Cu₁, Zr₁, Nb₁, Mo₁, Ru₁, Rh₁, Pd₁, Ag₁, W₁, Re₁, Os₁, Ir₁, Pt₁, and Au₁) atoms supported on graphyne (GY) surface for HER/OER and ORR using first-principle calculations. Ab initio molecular dynamics (AIMD) simulations and phonon dispersion spectra reveal the dynamic and thermal stabilities of the GY surface. The exceptional stability of all supported STM₁ atoms within the H1 cavity of the GY surface exists in an isolated form, facilitating the uniform distribution and proper arrangement of single atoms on GY. In particular, Sc₁, Co₁, Fe₁, and Au₁/GY demonstrate promising catalytic efficiency in the HER due to idealistic ΔG_H* values via the Volmer-Heyrovsky pathway. Notably, Sc₁ and Au₁/GY exhibit superior HER catalytic activity compared to other studied catalysts. Co₁/GY catalyst exhibits higher selectivity and activity for the OER, with an overpotential (0.46 V) comparable to MoC₂, IrO₂, and RuO₂. Also, Rh₁ and Co₁/GY SACs exhibited promising electrocatalysts for the ORR, with an overpotential of 0.36 and 0.46 V, respectively. Therefore, Co₁/GY is a versatile electrocatalyst for metal-air batteries and water-splitting. This study further incorporates computational analysis of the kinetic potential energy barriers of Co₁ and Rh₁ in the OER and ORR. A strong correlation is found between the estimated kinetic activation barriers for the thermodynamic outcomes and all proton-coupled electron transfer steps. We establish a relation for the Gibbs free energy of intermediates to understand the mechanism of SACs supported on STM₁/GY and introduce a key descriptor. This study highlights GY as a favorable single-atom support for designing highly active and cost-effective versatile electrocatalysts for practical applications.

In this article, we report a 3D NiFe phosphite oxyhydroxide plastic electrode using high-resolution digital light processing (DLP) 3D-printing technology via induced chemical deposition method. The as-prepared 3D plastic electrode exhibits no template requirement, freedom design, low-cost, robust, anticorrosion, lightweight, and micro-nano porous characteristics. It can be drawn to the conclusion that highly oriented open-porous 3D geometry structure will be beneficial for improving surface catalytic active area, wetting performance, and reaction–diffusion dynamics of plastic electrodes for oxygen evolution reaction (OER) catalysis process. Density functional theory (DFT) calculation interprets the origin of high activity of NiFe(PO₃)O(OH) and demonstrates that the implantation of the –PO₃ can effectively bind the 3d orbital of Ni in NiFe(PO₃)O(OH), lead to the weak adsorption of intermediate, make electron more active to improve the conductivity, thereby lowing the transform free energy of *O to *OOH. The water oxidization performance of as-prepared 3D NiFe(PO₃)O(OH) hollow tubular (HT) lattice plastic electrode has almost reached the state-of-the-art level compared with the as-reported large-current-density catalysts or 3D additive manufactured plastic/metal-based electrodes, especially for high current OER electrodes. This work breaks through the bottleneck that plagues the performance improvement of low-cost high-current electrodes.

Developing anode materials with high specific capacity and cycling stability is vital for improving thin-film lithium-ion batteries. Thin-film zinc oxide (ZnO) holds promise due to its high specific capacity, but it suffers from volume changes and structural stress during cycling, leading to poor battery performance. In this research, we ingeniously combined polytetrafluoroethylene (PTFE) with ZnO using a radio frequency (RF) magnetron co-sputtering method, ensuring a strong bond in the thin-film composite electrode. PTFE effectively reduced stress on the active material and mitigated volume change effects during Li⁺ ion intercalation and deintercalation. The composite thin films are thoroughly characterized using advanced techniques such as X-ray diffraction, scanning electron microscopy, and X-ray photoelectron spectroscopy for investigating correlations between material properties and electrochemical behaviors. Notably, the ZnO/PTFE thin-film electrode demonstrated an impressive specific capacity of 1305 mAh g⁻¹ (=7116 mAh cm⁻³) at a 0.5C rate and a remarkable capacity retention of 82% from the 1st to the 100th cycle, surpassing the bare ZnO thin film (50%). This study provides valuable insights into using binders to stabilize active materials in thin-film batteries, enhancing battery performance.

Anion exchange membrane fuel cell (AEMFC) technology is attracting intensive attention, due to its great potential by using non-precious-metal catalysts (NPMCs) in the cathode and cheap bipolar plate materials in alkaline media. However, in such case, the kinetics of hydrogen oxidation reaction (HOR) in the anode is two orders of magnitude sluggish than that of acidic electrolytes, which is recognized as the grand challenge in this field. Herein, we report the rationally designed Ni nanoparticles encapsulated by N-doped graphene layers (Ni@NG) using a facile pyrolysis strategy. Based on the density functional theory calculations and electrochemical performance analysis, it is witnessed that the rich Pyridinic-N within the graphene shell optimizes the binding energy of the intermediates, thus enabling the fundamentally enhanced activity for HOR with robust stability. As a proof of concept, the resultant Ni@NG sample as the anode with a low loading (1.8 mg cm⁻²) in AEMFCs delivers a high peak power density of 500 mW cm⁻², outperforming all of those of NPMC-based analogs ever reported.

In this work, we reported a series of monolithic 3D-printed Ni–Mo alloy electrodes for highly efficient water splitting at high current density (1500 mA cm⁻²) with excellent stability, which provides a solution to scale up Ni–Mo catalysts for HER to industry use. All possible Ni–Mo metal/alloy phases were achieved by tuning the atomic composition and heat treatment procedure, and they were investigated through both experiment and simulation, and the optimal NiMo phase shows the best performance. Density functional theory (DFT) calculations elucidate that the NiMo phase has the lowest H₂O dissociation energy, which further explains the exceptional performance of NiMo. In addition, the microporosity was modulated via controlled thermal treatment, indicating that the 1100 °C sintered sample has the best catalytic performance, which is attributed to the high electrochemically active surface area (ECSA). Finally, the four different macrostructures were achieved by 3D printing, and they further improved the catalytic performance. The gyroid structure exhibits the best catalytic performance of driving 500 mA cm⁻² at a low overpotential of 228 mV and 1500 mA cm⁻² at 325 mV, as it maximizes the efficient bubble removal from the electrode surface, which offers the great potential for high current density water splitting.

The systematic advances in the power conversion efficiency (PCE) and stability of perovskite solar cells (PSCs) have been driven by the developments of perovskite materials, electron transport layer (ETL) materials, and interfacial passivation between the relevant layers. While zinc oxide (ZnO) is a promising ETL in thin film photovoltaics, it is still highly desirable to develop novel synthetic methods that allow both fine-tuning the versatility of ZnO nanomaterials and improving the ZnO/perovskite interface. Among various inorganic and organic additives, zwitterions have been effectively utilized to passivate the perovskite films. In this vein, we develop novel, well-characterized betaine-coated ZnO QDs and use them as an ETL in the planar n-i-p PSC architecture, combining the ZnO QDs-based ETL with the ZnO/perovskite interface passivation by a series of ammonium halides (NH₄X, where X = F, Cl, Br). The champion device with the NH₄F passivation achieves one of the highest performances reported for ZnO-based PSCs, exhibiting a maximum PCE of ~22% with a high fill factor of 80.3% and competitive stability, retaining ~78% of its initial PCE under 1 Sun illumination with maximum power tracking for 250 h.

Lithium metal batteries (LMBs) and anode-free LMBs (AFLMBs) present a solution to the need for batteries with a significantly superior theoretical energy density. However, their adoption is hindered by low Coulombic efficiency (CE) and rapid capacity fading, primarily due to the formation of unstable solid electrolyte interphase (SEI) layer and Li dendrite growth as a result of uneven Li plating. Here, we report on the use of a stoichiometric Ti₃C₂T_x (S-Ti₃C₂T_x) MXene coating on the copper current collector to enhance the cyclic stability of an anode-free lithium metal battery. The S-Ti₃C₂T_x coating provides abundant nucleation sites, thereby lowering the overpotential for Li nucleation, and promoting uniform Li plating. Additionally, the fluorine (−F) termination of S-Ti₃C₂T_x participates in the SEI formation, producing a LiF-rich SEI layer, vital for stabilizing the SEI and improving cycle life. Batteries equipped with S-Ti₃C₂T_x@Cu current collectors displayed reduced Li consumption during stable SEI formation, resulting in a significant decrease in capacity loss. AFLMBs with S-Ti₃C₂T_x@Cu current collectors achieved a high initial capacity density of 4.2 mAh cm⁻², 70.9% capacity retention after 50 cycles, and an average CE of 98.19% in 100 cycles. This innovative application of MXenes in the energy field offers a promising strategy to enhance the performance of AFLMBs and could potentially accelerate their commercial adoption.

The accurate representation of lithium plating and aging phenomena has posed a persistent challenge within the battery research community. Empirical evidence underscores the pivotal role of cell structure in influencing aging behaviors and lithium plating within lithium-ion batteries (LIBs). Available lithium-ion plating models often falter in detailed description when integrating the structural intricacies. To address this challenge, this study proposes an innovative hierarchical model that intricately incorporates the layered rolling structure in cells. Notably, our model demonstrates a remarkable capacity to predict the non-uniform distribution of current density and overpotential along the rolling direction of LIBs. Subsequently, we delve into an insightful exploration of the structural factors that influence lithium plating behavior, leveraging the foundation laid by our established model. Furthermore, we easily update the hierarchical model by considering aging factors. This aging model effectively anticipates capacity fatigue and lithium plating tendencies across individual layers of LIBs, all while maintaining computational efficiency. In light of our findings, this model yields novel perspectives on capacity fatigue dynamics and local lithium plating behaviors, offering a substantial advancement compared to existing models. This research paves the way for more efficient and tailored LIB design and operation, with broad implications for energy storage technologies.

Symmetrical solid oxide cells (SSOCs) are very useful for energy generation and conversion. To fabricate the electrode of SSOC, it is very time-consuming to use the conventional approach. In this work, we design and develop a novel method, extreme heat treatment (EHT), to rapidly fabricate electrodes for SSOC. We show that by using the EHT method, the electrode can be fabricated in seconds (the fastest method to date), benefiting from enhanced reaction kinetics. The EHT-fabricated electrode presents a porous structure and good adhesion with the electrolyte. In contrast, tens of hours are needed to prepare the electrode by the conventional approach, and the prepared electrode exhibits a dense structure with a larger particle size due to the lengthy treatment. The EHT-fabricated electrode shows desirable electrochemical performance. Moreover, we show that the electrocatalytic activity of the perovskite electrode can be tuned by the vigorous approach of fast exsolution, deriving from the increased active sites for enhancing the electrochemical reactions. At 900 °C, a promising peak power density of 966 mW cm⁻² is reached. Our work exploits a new territory to fabricate and develop advanced electrodes for SSOCs in a rapid and high-throughput manner.