Energy & Environmental Science最新文献

Metal-oxide coatings are a favoured strategy for mitigating surface degradation problems in state-of-the-art lithium-ion battery Ni-rich layered positive electrode materials. Despite their extensive use, a full, fundamental understanding of the role of coatings in reducing degradation and extending cycling lifetimes is currently lacking. In this work, the interactions between an atomic layer deposited (ALD) alumina coating on polycrystalline LiNi_0.8Mn_0.1Co_0.1O₂ (NMC811) and a carbonate-based battery electrolyte are studied. Solid-state nuclear magnetic resonance (ssNMR) heteronuclear experiments show that the Al₂O₃ coating transforms by reacting with electrolyte species present before and during electrochemical cycling, scavenging protic and acidic species. Density-functional theory calculations highlight the additional chemical effect of the coating in locally stabilising the structure of the NMC811, limiting oxidation of the oxygen atoms coordinated to both Al and Ni, thereby limiting the surface reconstruction process and improving the electrochemical performance. Improved NMC811 surface stability is confirmed by monitoring gaseous degradation species by online electrochemical mass-spectrometry and via X-ray spectroscopic analysis of the electrochemically aged samples to examine changes in Ni and O oxidation state and local structure. The combination of this experimental and theoretical analysis suggests that Al₂O₃ coatings have a dual role: as a protective barrier against attack from chemical species in the electrolyte, and as an artificial passivating layer hindering oxygen loss and surface phase transformations. This holistic approach, which provides a fundamental understanding of how the surface stability is improved by the coating, will aid the design of the state-of-the-art and future positive electrode materials.

Electrocatalytic water splitting, a promising alternative to fossil fuels, has substantial potential for hydrogen generation. However, developing efficient electrocatalysts for the hydrogen evolution reaction (HER) faces challenges, especially in alkaline environments due to slow kinetics. Herein, we report supported ruthenium particles with iron alloying (RuFe/FeNC) as an effective HER catalyst under alkaline conditions. RuFe/FeNC demonstrates an ultralow overpotential of 9.3 mV and a high turnover frequency (TOF) of 1.35 H₂ s⁻¹ at −0.025 V_RHE, obviously surpassing the benchmark 20% Pt/C. Our analysis, employing techniques such as electrochemistry, in situ spectroscopic techniques, density functional theory, and ab initio molecular dynamics, shows that Fe sites modulate the electrode–electrolyte interface microstructure effectively. This modulation increases the population of H-down interfacial water molecules, weakening hydrogen-bond interactions over the catalyst surface and enhancing water dissociation at Ru sites. Additionally, it creates electron-rich Ru sites and electron-deficient Fe sites. Ru sites optimize hydrogen adsorption Gibbs free energy, acting as proton aggregators, while Fe sites collect hydroxides, mitigating adverse site blocking effects on Ru sites. Integrating these factors is crucial for the high HER activity of RuFe/FeNC, offering a new perspective on enhancing HER performance by controlling interfacial structure through doping.

To explain reported solar interfacial-evaporation rates from porous materials beyond an apparent 100% efficiency using the thermal evaporation mechanism, many publications hypothesize that intermediate water inside porous materials has a reduced latent heat. Key supporting evidence is that water-only surfaces have lower natural evaporation rates than porous evaporators, with the ratio of the two rates taken as the latent heat reduction. Through simulations and experiments, we study natural evaporation of water and show that reported differences in evaporation rates between porous materials and water are likely due to experimental error from recessed evaporating surfaces. A few millimeter recession of the water surface relative to the container lip can drop evaporation rates by over 50% due to a stagnant air layer, suggesting that the comparative experiments are prone to error. Furthermore, in the reduced latent heat picture, interfacial cooling must occur at the porous sample–water interface due to the enthalpy difference between bulk water and intermediate water. Our transport modeling shows that reduced latent heat cannot explain superthermal evaporation and that new mechanistic directions need to be pursued.

Triboelectric–electromagnetic hybrid nanogenerators (TE-HNGs) are promising for efficient energy harvesting, particularly from high-energy-density water waves. However, existing TE-HNGs often suffer from mechanical combinations and lack comprehensive energy optimization strategies, resulting in a suboptimal overall effect where 1 + 1 ≤ 2. Herein, a highly coupled energy self-managed power system (ESPS) is proposed based on our meticulously designed multilayer magnetic suspension hybrid nanogenerator (MS-HNG) with triboelectric and electromagnetic units. Due to voltage phase coherence between the generators, the magnetic suspension electromagnetic generator (MS-EMG) serves as the gate drive source for metal oxide semiconductor field-effect transistors, enabling the instantaneous release of energy from the magnetic suspension triboelectric nanogenerator (MS-TENG) and thereby maximizing energy output within each cycle. The ESPS achieves a peak power of 261.3 mW, a significant improvement over 75.5 mW from the MS-HNG alone, illustrating a synergistic effect where 1 + 1 > 2. Additionally, the ESPS achieves a current of 45 mA (a 7500% increase) and a power density of 631 W m⁻³ (a 346% increase). In water wave environments, this system can power 32 bulbs of 3 W each and perform water quality monitoring. This work represents a new breakthrough in the structural and circuit coupling of TE-HNGs, marking a milestone towards commercialization.

Manufacturing complexities and uncertainties have impeded the transition from material prototypes to commercial batteries, making their verification a critical quality assessment link. A fundamental challenge is to decouple electrochemical interactions for establishing a quantitative mapping from electrochemical parameters to macro battery performance. Here, we show that the proposed physics-informed learning model can quantify and visualize temporally resolved thermodynamic and kinetic parameters from field accessible electric signals, facilitating a non-destructive degradation pattern decoupling. The lifetime trajectory prediction is 25 times faster than the traditional capacity calibration test while retaining a 95.1% average accuracy across temperatures, underpinned by projected electrochemical data from early cycle observations which have not yet been established. We rationalize this predictability to the interpretation of statistical insights from material-agnostic featurization, excited by a multistep charging scheme with different current intensities and their switching conditions. The waste management of defective prototypes is enabled by statistically and non-destructively interpreting internal electrochemical states, demonstrating a 19.76 billion USD defective material recycling market by 2060. This paper highlights the potential of revisiting electrochemical degradation behaviors using physics-informed learning and dynamic current excitations, facilitating next-generation battery manufacturing, reuse, and recycling sustainability.

Two-dimensional (2D) nanocarbon-based materials with controllable pore structures and hydrophilic surfaces exhibit significant potential in various applications. However, traditional methods often encounter challenges in achieving these 2D carbon nanomaterials effectively. In this study, we present a scalable approach for the preparation of porous ultrathin nitrogen-doped carbon nanosheets decorated with ultrafine FeTe₂ nanoparticles (FeTe₂/CN), derived from metal–organic frameworks (MOFs) through a mild and modifier-free synthesis strategy. This graphene-like structure serves as a promising cathode material to address complex challenges in lithium–sulfur batteries (LSBs). Experimental results and density functional theory (DFT) calculations highlight the distinct advantages of this structure: (1) synergistic adsorption occurs through the lithiophilic sites of CN and the sulfiphilic sites of FeTe₂, efficiently capturing lithium polysulfides (LiPS); (2) enhanced conductivity of the CN nanosheets, combined with the robust spin state effect of FeTe₂, accelerates electron transfer and reduces energy barriers, thereby improving sulfur redox reaction (SRR) kinetics; (3) the graphene-like CN nanosheets provide numerous active sites and mitigate volume expansion during cycling. Consequently, LSBs based on S@FeTe₂/CN cathodes exhibit high initial capacity, exceptional rate performance, and outstanding stability. This work offers a novel strategy for preparing 2D nanocarbon-based materials with highly exposed active sites to enhance SRR efficiency.