Rare Metals最新文献

Aqueous zinc-ion batteries (AZIBs) have developed rapidly in recent years but still face several challenges, including zinc dendrites growth, hydrogen evolution reaction, passivation and corrosion. The pH of the electrolyte plays a crucial role in these processes, significantly impacting the stability and reversibility of Zn²⁺ deposition. Therefore, pH-buffer tris (hydroxymethyl) amino methane (tris) is chosen as a versatile electrolyte additive to address these issues. Tris can buffer electrolyte pH at Zn/electrolyte interface by protonated/deprotonated nature of amino group, optimize the coordination environment of zinc solvate ions by its strong interaction with zinc ions, and simultaneously create an in-situ stable solid electrolyte interface membrane on the zinc anode surface. These synergistic effects effectively restrain dendrite formation and side reactions, resulting in a highly stable and reversible Zn anode, thereby enhancing the electrochemical performance of AZIBs. The Zn||Zn battery with 0.15 wt% tris additives maintains stable cycling for 1500 h at 4 mA·cm⁻² and 1120 h at 10 mA·cm⁻². Furthermore, the Coulombic efficiency reaches ~ 99.2% at 4 mA·cm⁻²@1 mAh·cm⁻². The Zn||NVO full batteries also demonstrated a stable specific capacity and exceptional capacity retention.

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Recently, high-entropy materials are attracting enormous attention in battery applications, encompassing both electrode materials and solid electrolytes, due to the pliability and diversification in material composition and electronic structure. Theoretically, the rapid ion transport and the abundance of surface defects in high-entropy materials suggest a potential for enhancing the performance of composite solid-state electrolytes (CPEs). Herein, using a high-entropy oxide (HEO) filler to assess its potential contributions to CPEs is proposed. The distinctive structural distortions in HEO significantly improve the ionic conductivity (5 × 10⁻⁴ S·cm⁻¹ at 60 °C) and Li-ion transference number (0.57) of CPEs. Furthermore, the enhanced Li-ion transport capability extends the critical current density from 0.6 to 1.5 mA·cm⁻² in Li/Li symmetric cells. In addition, all-solid-state batteries incorporating the HEO-modified CPEs exhibit superior rate performance and cycling stability. The work will enrich the application of HEOs in CPEs and provide fundamental understanding.

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Designing rational transition-metal/carbon composites with highly dispersed and firmly anchored nanoparticles (NPs) to prevent agglomeration and shedding is crucial for realizing excellent electrocatalytic performances. Herein, a biomass pore-confined strategy based on mesoporous willow catkin is explored to obtain uniformly dispersed CoFe NPs in N-doped carbon nanotubes and hollow carbon fibers (CoFe@N-CNTs/HCFs). The resultant catalyst exhibits enhanced electrocatalytic performance, which affords a half-wave potential of 0.86 V (vs. RHE) with a limited current density of 6.0 mA·cm⁻² for oxygen reduction reaction and potential of 1.67 V (vs. RHE) at 10 mA·cm⁻² in 0.1 M KOH for oxygen evolution reaction. When applied to rechargeable zinc–air batteries, a maximum power density of 340 mW·cm⁻² and long-term cyclic durability over 800 h are achieved. Such superior bifunctional electrocatalytic activities are ascribed to the biocarbon matrix with abundant mesopores and unobstructed hollow channels, CoFe NPs with high dispersion and controllable nanoscale and the hybrid composite with optimized electronic structure. This work presents an effective approach for constraining the size and dispersion of NPs in a low-cost biocarbon substrate, offering valuable insights for designing advanced oxygen electrocatalysts.

The zinc indium sulfide (ZnIn₂S₄) semiconductors have garnered significant interest in photocatalysis due to their environmentally friendly characteristics, appropriate bandgap, and high absorption coefficient. However, the exploration of advanced strategies to realize the effective and tailored doping still poses significant challenges in enhancing hydrogen evolution performance. In this work, a mild cation exchange strategy is reported to incorporate Ag cations into flower-like ZnIn₂S₄ microspheres, enabling the selective replacement of Zn atoms by Ag. Remarkably, the as-fabricated Ag-ZnIn₂S₄ exhibited exceptional photocatalytic hydrogen production performance, achieving a rate of 8098 μmol·g⁻¹· h⁻¹ under visible light irradiation. This is 4 times than that of pristine ZnIn₂S₄ (2002 μmol·g⁻¹· h⁻¹), and stands as the highest one among metal-doped-ZnIn₂S₄ photocatalysts ever reported. Along with the theoretical calculations, it has been confirmed that the enhanced photocatalytic hydrogen generation behavior can primarily be attributed to the synergistic effect with improved light absorption, reduced adsorption energy, increased active sites and optimized charge carrier transfer, induced by the cation exchange with Ag in ZnIn₂S₄. This work might provide some valuable insights on the design and development of highly efficient visible light driven photocatalysts for water splitting applications.

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The inherent safety, high theoretical specific capacity and low raw material cost of aqueous batteries make them potential candidates in large-scale energy storage. However, uncontrolled dendrite growth, parasitic reactions and sluggish mass transfer on the anode-electrolyte interface are the main challenges restricting the application prospect of aqueous zinc-ion batteries. In general, eukaryotic cells utilize specific ion channels to achieve ion migration with the merits of low energy consumption and rapid speed. Herein, migrating the concept of ion channels to aqueous batteries, a crown species encapsulated zeolitic imidazolate framework (ZIF) interfacial layer (denoted as ZIF@Crown) was ex situ decorated onto the Zn anode. Similar to biological ion channels, the ZIF@Crown layer can homogenize the distribution of Zn²⁺ on the anode, accelerate the desolvation of hydrated Zn²⁺ and reduce the energy barrier for Zn²⁺ deposition, which were verified by theoretical calculations and experimental characterizations. Benefiting from these efficacious modulation mechanisms, the Zn@ZIF@Crown symmetrical cell could achieve a long calendar life of over 1900 h and the Zn@ZIF@Crown||Cu also sustained 600 cycles with a high Coulombic efficiency (97%). Furthermore, the full cells containing ZIF@Crown layer exhibit desirable electrochemical performance. This work provides an innovative avenue toward the optimization of aqueous batteries via bionic interfacial engineering.

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One-dimensional nanomaterials with hollow structures could provide large space for ion storage and charge accumulation. Herein, TiO₂/MoSe₂-Carbon nanotube composite (NT) materials were designed and fabricated by the template method and the chelation coordination reaction. The stability and conductivity were improved by the presence of titanium and hollow tubular-architecture carbon in the whole structure. As a result, the as-prepared TiO₂/MoSe₂-Carbon hybrid achieved a high-rate performance of 760.0 mAh·g⁻¹ at a current density of 0.1 A·g⁻¹, while still obtaining stability after 300 charge/discharge cycles. The enhancement of the lithium storage capacity mainly contributed to the acceleration of the electron conductivity and the storage kinetics. Moreover, the hollow structure reduced the volume strain and stress caused by the rapid insertion and removal of lithium ions, which ensured the favorable stability of lithium storage. The experiment shows that the kinetic of the TiO₂/MoSe₂-carbon hybrid during the lithium storage process is dominated by the pseudocapacitance mechanism. This work provides a new idea and scheme for the design and preparation of hierarchical nanotube composite electrode materials.

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The rise in gas leakage incidents underscores the urgent need for advanced gas-sensing platforms with ultra-low concentration detection capability. Sensing gate field effect transistor (FET) gas sensors, renowned for the gas-induced signal amplification without directly exposing the channel to the ambient environment, play a pivotal role in detecting trace-level hazardous gases with high sensitivity and good stability. In this work, carbon nanotubes are employed as the conducting channel, and yttrium oxide (Y₂O₃) is utilized as the gate dielectric layer. Noble metal Pd is incorporated as a sensing gate for hydrogen (H₂) detection, leveraging its catalytic properties and unique adsorption capability. The fabricated carbon-based FET gas sensor demonstrates a remarkable detection limit of 20 × 10^–9 for H₂ under an air environment, enabling early warning in case of gas leakage. Moreover, the as-prepared sensor exhibited good selectivity, repeatability, and anti-humidity properties. Further experiments elucidate the interaction between H₂ and sensing electrode under an air/nitrogen environment, providing insights into the underlying oxygen-assisted recoverable sensing mechanism. It is our aspiration for this research to establish a robust experimental foundation for achieving high performance and highly integrated fabrication of trace gas sensors.

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Dual-element-doped Co-free Ni-rich LiNiO₂-based cathodes demonstrate great potential for high-energy lithium-ion batteries (LIBs). Nevertheless, they suffer from serious Li⁺/Ni²⁺ mixing, irreversible phase transitions, structural degradation and side reactions at the cathode/electrolyte interface. Herein, W is purposively introduced into LiNi_0.9Mn_0.05Ti_0.025Al_0.025O₂ to engineer rock-salt Li_4+xNi_1-xWO₆ stabilized LiNi_0.9Mn_0.035Ti_0.025Al_0.025W_0.015O₂ (LNMTAWO) cathode. In situ characterizations, together with electrochemical analysis, demonstrate that Mn, Ti and Al can effectively enhance the reversibility of phase transitions, stabilize the TM–O bonds under high voltage and relieve voltage decay. The rock-salt Li_4+xNi_1-xWO₆ can prevent the overgrowth of grain size, avoid the exposure of active materials into electrolytes and decrease the side reaction. Benefitting from the dual-element synergistic effects, the LNMTAWO cathode offers high reversible capacities of 228.7 and 150.8 mAh·g⁻¹ at 0.2C and 5C, respectively, and contributes a high reversible capacity of 171.4 mAh·g⁻¹ at 0.5C after 200 cycles (voltage delay: 5 mV) and 88.4 mAh·g⁻¹ at 10C after 500 cycles. Such design of rock-salt structure symbiotically grown on Ni-rich cathodes by introducing high-valence elements would provide rational guidelines on engineering high-energy Co-free Ni-rich LIB cathodes.

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