Wei Chen

Tuning the morphology and structure of Cu nanomaterials could effectively regulate their property, functions, and applications. However, it still remains challenging to directly synthesize Cu nanomaterials with an unconventional phase. Here, we report a one-pot wet-chemical synthesis of Cu nanocrystals (NCs) with a hexagonal close-packed (hcp, 2H type) phase, which is different from their thermodynamically stable face-centered cubic (fcc) phase. Compared to the conventional fcc-Cu NCs, the obtained 2H-Cu NCs exhibit enhanced catalytic activity and selectivity in the electrochemical carbon dioxide reduction reaction (CO2RR), achieving a high Faradaic efficiency (FE) of 73.1% toward multicarbon (C2+) products at 600 mA cm–2 under alkaline conditions in a flow cell. Moreover, in situ characterizations and density functional theory (DFT) calculations reveal that the 2H-Cu NCs can optimize the adsorption of the *CO intermediate, leading to a low energy barrier for the formation of C2+ products. This work not only demonstrates an improvement in CO2RR performance of Cu NCs by using the strategy of phase engineering of nanomaterials (PEN) but also opens up an avenue to explore the intrinsic properties and applications of unconventional-phase nanomaterials.

Silicon carbide (SiC) is a leading candidate for next‐generation power electronics. However, achieving reliable and low‐resistance metal/SiC contacts remains a challenge due to incomplete mechanistic understanding of the interplay between interfacial chemistry, electronic structure, and contact resistance. Here, we combine laboratory‐based and synchrotron‐based photoelectron spectroscopy (PES) to elucidate the evolution of the molybdenum (Mo)/4H‐SiC(0001) interface under different fabrication pathways. Distinct spectral features reveal Mo silicide (MoSi _x ) formation after annealing and demonstrate that direct Mo deposition on heated 4H‐SiC(0001) substrates enhances MoSi _x formation and yields a cleaner, more homogeneous interface, owing to altered Mo growth dynamics at elevated substrate temperatures. This interfacial MoSi _x layer strengthens electronic coupling and optimizes band alignment across the Mo/SiC junction, achieving authentic Ohmic contact with a tenfold reduction in contact resistance. These findings elucidate the electronic and chemical origins of low‐barrier Mo/SiC contacts, offering a practical, energy‐efficient route towards low‐resistance SiC‐based devices.

1,3‐dioxolane is a promising solvent for low‐temperature batteries owing to its low freezing point and low viscosity. However, its tendency toward ring‐opening polymerization leads to reduced ionic conductivity and deteriorated electrochemical stability. Here, we establish an electronic–geometric coupling design principle to regulate solvent stability in weak–weak electrolyte systems for sodium metal batteries. A dual‐descriptor framework combining ring strain energy (RSE) and a sterically corrected electrostatic descriptor, defined by the lowest negative electrostatic potential normalized by molecular volume (ESP _min /Volume), is introduced to guide cyclic ether solvent design. Following this principle, 2,4‐dimethyl‐1,3‐dioxolane is identified with reduced RSE and moderate ESP _min /Volume, enabling enhanced resistance to polymerization and improved Na‐compatibility/ion transport. Molecular dynamics simulations and density functional theory calculations reveal that, the electrolyte forms an aggregate‐dominated solvation structure with a high lowest unoccupied molecular orbital level, promoting the formation of a thin, uniform, and inorganic‐rich solid electrolyte interphase. Consequently, the electrolyte delivers accelerated interfacial kinetics and stable operation across a wide temperature range. Na||Na symmetric cells cycle stably for 1800 h at room temperature, while Na||Na ₃ V ₂ (PO ₄ ) ₃ full cells with high cathode loading (20 mg cm ⁻² ) operate for over 200 cycles at 25 °C and more than 900 cycles at −40° C.

1,3‐dioxolane is a promising solvent for low‐temperature batteries owing to its low freezing point and low viscosity. However, its tendency toward ring‐opening polymerization leads to reduced ionic conductivity and deteriorated electrochemical stability. Here, we establish an electronic–geometric coupling design principle to regulate solvent stability in weak–weak electrolyte systems for sodium metal batteries. A dual‐descriptor framework combining ring strain energy (RSE) and a sterically corrected electrostatic descriptor, defined by the lowest negative electrostatic potential normalized by molecular volume (ESP _min /Volume), is introduced to guide cyclic ether solvent design. Following this principle, 2,4‐dimethyl‐1,3‐dioxolane is identified with reduced RSE and moderate ESP _min /Volume, enabling enhanced resistance to polymerization and improved Na‐compatibility/ion transport. Molecular dynamics simulations and density functional theory calculations reveal that, the electrolyte forms an aggregate‐dominated solvation structure with a high lowest unoccupied molecular orbital level, promoting the formation of a thin, uniform, and inorganic‐rich solid electrolyte interphase. Consequently, the electrolyte delivers accelerated interfacial kinetics and stable operation across a wide temperature range. Na||Na symmetric cells cycle stably for 1800 h at room temperature, while Na||Na ₃ V ₂ (PO ₄ ) ₃ full cells with high cathode loading (20 mg cm ⁻² ) operate for over 200 cycles at 25 °C and more than 900 cycles at −40° C.

Artificial solid electrolyte interphase offers a promising route to improve the lifespan and safety of quasi-solid-state sodium-metal batteries (QSMBs), yet its limited ion conductivity and the low liquidity of the polymer electrolyte often result in unstable Na plating/stripping kinetics and poor interfacial durability. Herein, we propose a surface-induced “top” Na deposition mechanism facilitated by an ultra-sodiophilic ionic/electronic mixed conductor interphase exhibiting strong Na ⁺ adsorption affinity, which ensures fast and dendrite-free Na anode operation. The embedded Na ₃ Sb alloy phase, featuring high electronic conductivity and strong Na ⁺ adsorption energy, significantly accelerates interfacial ion diffusion and nucleation kinetics, forming a smooth and compact Na deposition layer that facilitates stable solid electrolyte interphase formation and preserves interfacial integrity. Consequently, Na||Na symmetric cells employing a 1, 3-dioxolane-based gel polymer electrolyte deliver an ultra-long-cycling lifespan of 1000 h at 0.5 mA cm ⁻² with a low overpotential of 40 mV. Moreover, QSMBs incorporating the modified Na anode and Na ₃ V ₂ (PO ₄ ) ₃ cathode demonstrate outstanding cycling stability (74.1% capacity retention after 9000 cycles at 2C) and superior rate capability (91.7 mAh g ⁻¹ at 5C). The work provides mechanistic insights and practical strategies for regulating Na deposition, paving the way toward high-performance QSMBs.

Thickness and pressure cooperatively modulate the transport properties in layered materials─particularly two-dimensional (2D) superconductivity─which are intrinsically governed by quantum confinement and anisotropic interactions. Here, through systematic investigation of thickness-dependent pressure-induced phenomena in black phosphorus, we reveal the mechanism by which dimensional confinement governs metallization and superconductivity via modulation of the electronic structure. Robust 2D superconductivity, observed in both few-layer samples and nanoflakes within the bulk, underscores quantum confinement as the fundamental origin of 2D superconductivity. Furthermore, the 3D-2D crossover in bulk highlights the critical role of weak interlayer coupling in stabilizing 2D superconducting behavior. Remarkably, quantum confinement dramatically enhances the critical field, with the in-plane critical field in 6-layer sample exceeding the Pauli limit due to enhanced spin-orbit scattering. These findings provide new insights into engineering superconducting dimensionality and properties via combined thickness and pressure control.

Calcium metal batteries represent a promising frontier for high‐energy‐density energy storage, yet their practical application is hindered by sluggish kinetics and unstable electrolyte‐metal interfaces. Here, we report an electrolyte design strategy based on an asymmetric solvation effect by a hybrid Ca ²⁺ /Na ⁺ organoborate electrolyte that simultaneously regulates solvation chemistry and interphase formation. By introducing monovalent co‐cations and strongly coordinating tetra(3,3,3‐trifluoropropoxy)borate anion, an asymmetric solvation structure is constructed in which electrochemically active Ca ²⁺ occupies an off‐center position. This configuration significantly breaks the centrosymmetry of the Ca ²⁺ solvation sheath, leading to an intensified dipole moment and a disruption of the uniform electrostatic shielding, which selectively activates the Ca ²⁺ for efficient desolvation. Consequently, dense Ca deposition (>10 mA h cm ⁻² ) is achieved with low overpotential, high reversibility (∼95%), and long‐term stability. Interfacial analysis reveals that the asymmetric solvation environment drives preferential anion decomposition, yielding a polymeric‐polycrystalline interphase composed of CaH ₂ /CaO and boron‐containing polymeric ether species that effectively protects the Ca anode. When paired with cathodes under a restricted negative‐to‐positive ratio of 7.2, the Ca/Na/Btfp electrolyte enables stable full‐cell operation to exceed 57 cycles. This strategy is also transferable to Mg metal battery, highlighting its potential as a general electrolyte design principle for multivalent metal batteries.

Calcium metal batteries represent a promising frontier for high‐energy‐density energy storage, yet their practical application is hindered by sluggish kinetics and unstable electrolyte‐metal interfaces. Here, we report an electrolyte design strategy based on an asymmetric solvation effect by a hybrid Ca ²⁺ /Na ⁺ organoborate electrolyte that simultaneously regulates solvation chemistry and interphase formation. By introducing monovalent co‐cations and strongly coordinating tetra(3,3,3‐trifluoropropoxy)borate anion, an asymmetric solvation structure is constructed in which electrochemically active Ca ²⁺ occupies an off‐center position. This configuration significantly breaks the centrosymmetry of the Ca ²⁺ solvation sheath, leading to an intensified dipole moment and a disruption of the uniform electrostatic shielding, which selectively activates the Ca ²⁺ for efficient desolvation. Consequently, dense Ca deposition (>10 mA h cm ⁻² ) is achieved with low overpotential, high reversibility (∼95%), and long‐term stability. Interfacial analysis reveals that the asymmetric solvation environment drives preferential anion decomposition, yielding a polymeric‐polycrystalline interphase composed of CaH ₂ /CaO and boron‐containing polymeric ether species that effectively protects the Ca anode. When paired with cathodes under a restricted negative‐to‐positive ratio of 7.2, the Ca/Na/Btfp electrolyte enables stable full‐cell operation to exceed 57 cycles. This strategy is also transferable to Mg metal battery, highlighting its potential as a general electrolyte design principle for multivalent metal batteries.