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To address the challenges of high error rates and poor generalization in current deep learning models for predicting lattice thermal conductivity (LTC), we introduce CrysGraphFormer, an innovative equivariant crystal graph transformer model tailored for this task. The model incorporates an improved multi-head self-attention mechanism and human-designed feature descriptors. By utilizing a message-passing mechanism to update node information, it introduces relative coordinate differences to represent crystal symmetry, avoiding the traditionally used complex and computationally expensive higher-order representations. We constructed a comprehensive dataset containing 5729 LTC data points (300 K), including 5477 materials from AFLOW, 112 MAX and MAB phase materials calculated using VASP, and 140 for half-Heusler alloys. Experimental results demonstrate that the CrysGraphFormer model achieves state-of-the-art performance in LTC prediction tasks and excels in predicting fundamental properties. The model offers good interpretability, providing insights from chemical and materials science perspectives. Furthermore, we validated the model's application potential in the field of thermoelectric materials by predicting the LTC of 59 thermoelectric materials and 55 ternary semiconductor materials, with results consistent with DFT calculations. Finally, the uncertainty of CrysGraphFormer was assessed using the Monte Carlo Dropout method. [ABSTRACT FROM AUTHOR]

Flexible wearable electronics are in urgent need of advanced micro‐energy storage devices. MXenes are widely used in supercapacitors because of their excellent conductivity and hydrophilicity. Nevertheless, MXene‐based supercapacitors typically exhibit low capacitance and unsatisfied rate performance, particularly in the solid compact MXene film electrode with limited porosity and/or ion diffusion paths. Here, the synthesis of MXene inks with enlarged interlayer spacing for facilitated ion diffusion kinetics by intercalating lithium ions is reported. The ion‐intercalated MXene inks are further screen‐printed for scalable production of MXene‐based micro‐supercapacitors (MSCs). Benefiting from such an electrode architecture design, as well as the wide voltage window of 21 m bis(trifluoromethane)sulfonimide lithium (LiTFSI) water‐in‐salt electrolyte, the device exhibits impressive areal capacitance (252 mF cm−2), much‐improved rate performance (capacitance retention rate as high as 80%), excellent cyclic stability (retains 98.4% of initial capacitance after 10 000 cycles) and flexibility, showing great potential in the field of wearable intelligent electronics. [ABSTRACT FROM AUTHOR]

Uranium is considered as a very important nuclear energy material because of the huge amount of energy it releases. As the main product of the spontaneous decay of uranium, it is difficult for helium to react with uranium because of its chemical inertness. Therefore, bubbles will be formed inside uranium, which could greatly reduce the performance of uranium or cause safety problems. Additionally, nuclear materials are usually operated in an environment of high-temperature and high-pressure, so it is necessary to figure out the exact state of helium inside uranium under extreme conditions. Here, we explored the structural stability of the U–He system under high pressure and high temperature by using density functional theory calculations. Two metastable phases are found between 50 and 400 GPa: U4He with space group Fmmm and U6He with space group P1¯. Both are metallic and adopt layered structures. Electron localization function calculation combined with charge density difference analysis indicates that there are covalent bonds between U and U atoms in both Fmmm-U4He and P1¯-U6He. Regarding the elastic modulus of α-U, the addition of helium has certain influence on the mechanical properties of uranium. Besides, first-principles molecular dynamics simulations were carried out to study the dynamical behavior of Fmmm-U4He and P1¯-U6He at high-temperature. It was found that Fmmm-U4He and P1¯-U6He undergo one-dimensional superionic phase transitions at 150 GPa. Our study revealed the exotic structure of U–He compounds beyond the formation of bubbles under high-pressure and high-temperature, which might be relevant to the performance and safety issues of nuclear materials under extreme conditions. [ABSTRACT FROM AUTHOR]

Lattice thermal conductivity ( k lat ) of mantle minerals is a key factor in determining the Earth's energy budget and influences its dynamic processes. Here, we trained a neuroevolution machine learning potential for CaSiO3 perovskite (CaPv), the third most abundant mineral of the lower mantle, to investigate the k lat of pyrolitic aggregates at the core–mantle boundary (CMB). We show that the k lat of two types of pyrolitic aggregates has increased by 7% and 5% upon the addition of CaPv, demonstrating its significance in shaping the thermal structure of Earth's interior. Considering other mantle minerals and iron content, as well as the global distribution of temperature, we evaluated the heat flow across the CMB to be 7.98 ± 0.4 TW. The estimated heat flow is inconsistent with the value derived from the Fe alloy, which might suggest the presence of a thermally or chemically stratified layer atop the outer core. [ABSTRACT FROM AUTHOR]

A shock-release model is proposed to calculate shock temperatures along the principal Hugoniot, and to relate initial shock (Hugoniot) to release melting (off-Hugoniot). Thus a melting point crossing the Hugoniot can be defined. For the shock-release model, an assumed configuration of baseplate(metal-sample)/window is modeled to formulate the initial shock and interfacial release processes, the Lindemann law is used to describe the melting behavior of metals at high pressure, and the Grüneisen equation of state is applied to express the relation between pressure and specific internal energy. The effect of melting on the Hugoniot temperature is considered in this model, so the pressure-temperature regime of solid-liquid mixed phase region can be outlined. Aluminum, lead, copper, molybdenum, iron, and uranium were chosen for modeling calculations. It was found from the comparison of calculated results with their high-pressure melting data from experimental measurements that for most investigated metals γ = γ[SUB0](ρ[SUB0]/ρ) (where γ and ρ are Grüneisen parameter and density, respectively, and subscript 0 denotes ambient conditions) is a good approximation to γ at high pressure, and the melting latent heat (ΔH[SUBM]) at high pressure is better estimated using ΔH[SUBM] = RT[SUBM] (where T[SUBM] is the melting temperature, and R is the gas constant) than using ΔH[SUBM] =T[SUBM]· ΔAS[SUBM0] (where ΔS[SUBM0] is the melting entropy at ambient pressure). [ABSTRACT FROM AUTHOR]

Sodium-ion batteries (SIBs) have grabbed worldwide attention as an alternative to lithium-ion batteries on account of the abundance and accessibility of the sodium element in nature. For the sake of meeting the requirements for various applications containing grid-scale energy storage system, electric vehicles, and so forth, a stable and high-voltage cathode is decisive to enhance the energy and power density of SIBs. In this research, sodium super ionic conductor structured Na 3 V 1.5- x Cr 0.5+ x (PO 4 ) 3 with different V/Cr ratios to balance the V 3+ /V 4+ and V 4+ /V 5+ redox couples was investigated as the potential cathode for SIBs. Among these candidates, Na 3 V 1.3 Cr 0.7 (PO 4 ) 3 manifested high energy density together with good cycling performance and rate capability. Combining the structural analysis and density functional theory calculation, the underlying mechanism of V 3+ substitution by Cr 3+ was uncovered, accounting for the improvement of electrochemical performance.