Yinggan Zhang

We achieve efficient photogenerated charge separation and solar hydrogen production by constructing two-dimensional polar van der Waals heterostructures with a built-in electric field.

Graph neural networks (GNNs) have been widely used in materials science due to their ability to process complex graph‐structured data by capturing the relationships between atoms, molecules, or crystal structures within materials. However, due to the lack of interpretability, GNN acts as a “black box” model in most cases. In this work, by introducing the attention mechanism into GNN, a graph attention neural network (GANN) model for 2D materials is proposed, which not only reaches accurate prediction performances but also shows interpretability via attention mechanism analysis. Taking Janus III–VI van der Waals heterostructures as a representative case, the MAE for predicting formation energy, lattice constants, PBE bandgap, and HSE06 bandgap are 0.009 eV, 0.003 Å, 0.087, and 0.123 eV, respectively. Remarkably, the GANN model shows outstanding generalizable ability that can achieve accurate prediction using guessed input structures without fully structural relaxation to reach the ground state for Janus III–VI vdW heterostructures. Furthermore, the attention mechanisms of integration enable qualitative analysis of the contributions of the nearest neighboring atoms, endowing the GNN model with enhanced interpretability. Our findings offer novel perspectives for AI‐driven 2D material design by establishing an optimal balance between predictive accuracy and model interpretability in GNN approaches.

As a representative third-generation Al-Li alloy, 2A97 alloy has attracted significant attention for applications in aeronautics and astronautics, but its poor hot workability and complex thermal deformation behavior, which make for difficult optimization, significantly limit its widespread industrial utilization. In this study, the thermal deformation behavior of 2A97 Al-Li alloy was systematically investigated via thermal compression tests conducted over a temperature range of 260–460 °C and strain rates ranging from 0.001 s⁻¹ to 1 s⁻¹. The effects of deformation parameters on the alloy’s microstructural evolution were examined using electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM). Based on the dynamic materials model, a constitutive equation was established by analyzing the stress–strain data under various thermal deformation conditions. Furthermore, a thermal processing map was compiled to analyze the effects of the temperature and strain rate on the power dissipation efficiency and flow instability factor. The thermal deformation mechanisms were identified through combined analysis of the thermal processing map and microstructural features. Results indicate that the fraction of low-angle grain boundaries increases with a rising lnZ value (Zener–Hollomon parameter) during the thermal compression process. Dynamic recrystallization is the main deformation mechanism of 2A97 Al-Li alloy in the stable region, whereas the alloy exhibits flow localization in the unstable region. According to the thermal processing map, the optimal hot working windows for the 2A97 Al-Li alloy were determined to be (1) 360–460 °C at strain rates of 0.05 s⁻¹–1 s⁻¹, and (2) 340–420 °C at strain rates of 0.001 s⁻¹–0.005 s⁻¹. These conditions offer favorable combinations of microstructure and deformation stability, providing critical guidance for the thermo-mechanical processing of 2A97 alloy.

Sluggish redox kinetics and dendrite growth perplex the fulfillment of efficient electrochemistry in lithium-sulfur (Li-S) batteries. The complicated sulfur phase transformation and sulfur/lithium diversity kinetics necessitate an all-inclusive approach in catalyst design. Herein, a compatible mediator with nanoscale-asymmetric-size configuration by integrating Co single atoms and defective CoTe_2-x (Co_SA-CoTe_2-x@NHCF) is elaborately developed for regulating sulfur/lithium electrochemistry synchronously. Substantial electrochemistry and theoretical analyses reveal that CoTe_2-x exhibits higher catalytic activity in long-chain polysulfide transformation and Li₂S decomposition, while monodispersed Co sites are more effective in boosting sulfur reduction kinetics to regulate Li₂S deposition. Such cascade catalysis endows Co_SA-CoTe_2-x@NHCF with the all-around service of "trapping-conversion-recuperation" for sulfur species during the whole redox reaction. Furthermore, it is demonstrated by in situ transmission electron microscopy that initially formed electronic-conductive Co and ionic-conductive Li₂Te provide sufficient lithiophilic sites to regulate homogeneous Li plating and stripping with markedly suppressed dendrite growth. Consequently, by coupling the Co_SA-CoTe_2-x@NHCF interlayer and Li@Co_SA-CoTe_2-x@NHCF anode, the constructed Li-S full batteries deliver superior cycling stability and rate performance, and the flexible pouch cell exhibits stable cycling performance at 0.3 C. The gained insights into the synergistic effect of asymmetric-size structures pave the way for the integrated catalyst design in advanced Li-S systems.

Li-rich Mn-based cathode materials (LRM) have received great attention owing to their high capacity and low cost. However, the mismatch between the widely used carbonate electrolyte and the LRM cathode and lithium metal anode causes a series of problems, such as electrolyte continuous oxidation, cathode structure degradation, and Li dendritic growth. Herein, inorganic oxide B2O3 is introduced as a dual-functional high-voltage electrolyte additive to construct stable cathode electrolyte interphase and solid electrolyte interphase for Li||LRM batteries. The modified interface derived from the additive can induce dendrite-free Li deposition, stabilize cathode structure, and inhibit transition metal dissolution. Moreover, the adverse side reactions are mitigated, thus enhancing Li+ transport rate and reducing interface impedance. With the addition of B2O3 into the carbonate electrolyte, the Li||LRM battery exhibits an enhanced discharge capacity of 221 mAh g-1 after 200 cycles, equaling a capacity retention of 92.1%. When the upper cut-off voltage is increased to 5 V, a superior capacity retention of > 85% can still be achieved after 150 cycles at 1 C. In addition, the low cost of B2O3 benefits for commercial application. This work offers new guidance for the research of low-cost, high-voltage dual-functional additives for advanced lithium metal batteries.

Topological insulator Bi ₂ Se ₃ with a unique cloud-like hollow structure was synthesized and employed as a separator modifier for lithium–sulfur batteries, which can significantly accelerate sulfur conversion kinetics and mitigate the shuttle effect.

Two-dimensional van der Waals (vdW) heterostructures are potential candidates for clean energy conversion materials to address the global energy crisis and environmental issues. In this work, we have comprehensively studied the geometrical, electronic, and optical properties of M₂CO₂/MoX₂ (M = Hf, Zr; X = S, Se, Te) vdW heterostructures, as well as their applications in the fields of photocatalytic and photovoltaic using density functional theory calculations. The lattice dynamic and thermal stabilities of designed M₂CO₂/MoX₂ heterostructures are confirmed. Interestingly, all the M₂CO₂/MoX₂ heterostructures exhibit intrinsic type-II band structure features, which effectively inhibit the electron-hole pair recombination and enhance the photocatalytic performance. Furthermore, the internal built-in electric field and high anisotropic carrier mobility can separate the photo-generated carriers efficiently. It is noted that M₂CO₂/MoX₂ heterostructures exhibit suitable band gaps in comparison to the M₂CO₂ and MoX₂ monolayers, which enhance the optical-harvesting abilities in the visible and ultraviolet light zones. Zr₂CO₂/MoSe₂ and Hf₂CO₂/MoSe₂ heterostructures possess suitable band edge positions to provide the competent driving force for water splitting as photocatalysts. In addition, Hf₂CO₂/MoS₂ and Zr₂CO₂/MoS₂ heterostructures deliver a power conversion efficiency of 19.75% and 17.13% for solar cell applications, respectively. These results pave the way for exploring efficient MXenes/TMDCs vdW heterostructures as photocatalytic and photovoltaic materials.