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This study uses first-principles calculations to investigate the asymmetric Zr2CO/VSe2 heterostructure for hydrogen evolution reaction (HER) applications, focusing on its interlayer interactions, electronic structures, and HER performance across six stacking angles. Our findings demonstrate remarkable structural stability, characterized by interlayer distances of 2.1 Å to 2.7 Å and binding energies from −150.521 to −257.939 meV Å−2. Band structure analyses highlight the heterostructures' exceptional conductivity, essential for catalytic efficiency. Additionally, charge density difference calculations reveal significant charge transfer and redistribution at the interface, providing insights into the interlayer interactions and their influence on catalytic activity. Notably, the Gibbs free energy of hydrogen adsorption (ΔGH*) remains within ±0.1 eV across all configurations, indicating superior HER activity. Further analysis shows that the work function (Φ) serves as a critical electronic structure descriptor, influencing HER performance. The relationship between work function and ΔGH* across different interlayer distances underscores the predictive value of the work function for HER activity. These insights provide a theoretical foundation for developing advanced and effective non-noble metal HER catalysts, paving the way for innovations in sustainable energy technologies. [ABSTRACT FROM AUTHOR]

This investigation highlights the significant impact of asymmetric Janus Zr2COT (T = F, Cl, Br, I) monolayers on enhancing the hydrogen evolution reaction (HER) performance. Employing density functional theory (DFT), our research demonstrates that introducing asymmetric functional groups into Zr2COT structures effectively tailors their electronic properties, leading to a marked improvement in HER activity. This structural innovation notably reduces the hydrogen adsorption Gibbs free energy (ΔGH*) from 0.877 eV for the symmetric Zr2CO2 to below 0.2 eV for the Janus Zr2COT configurations, with Zr2COBr and Zr2COI achieving exceptionally low ΔGH* values of 0.045 and −0.042 eV, respectively, at a hydrogen coverage of 1/4. The monolayers also exhibit remarkable thermal stability and superior electrical conductivity, vital for high-efficiency electrocatalysis. Furthermore, strain engineering underscores the durability of these materials, maintaining ΔGH* values within ±0.2 eV under extensive tensile strain and emphasizing their practical application potential. Crucially, this work uncovers the critical role of electronic structure adjustments in optimizing the HER performance, aligning with the Sabatier principle, and offering fresh perspectives for designing effective, cost-efficient electrocatalysts. In a word, Janus Zr2COT monolayers emerge as promising candidates, challenging traditional noble metal catalysts and paving the way for the development of sustainable electrocatalytic materials. [ABSTRACT FROM AUTHOR]

Aqueous Mn-ion batteries (MIBs) exhibit a promising development potential due to their cost-effectiveness, high safety, and potential for high energy density. However, the development of MIBs is hindered by the lack of electrode materials capable of storing Mn 2+ ions due to acidic manganese salt electrolytes and large ion radius. Herein, the tunnel-type structure of monoclinic VO 2 nanorods to effectively store Mn 2+ ions via a reversible (de)insertion chemistry for the first time is reported. Utilizing exhaustive in situ/ex situ multi-scale characterization techniques and theoretical calculations, the co-insertion process of Mn 2+ /proton is revealed, elucidating the capacity decay mechanism wherein high proton activity leads to irreversible dissolution loss of vanadium species. Further, the Grotthuss transfer mechanism of protons is broken via a hydrogen bond reconstruction strategy while achieving the modulation of the electric double-layer structure, which effectively suppresses the electrode interface proton activity. Consequently, the VO 2 demonstrates excellent electrochemical performance at both ambient temperatures and -20 °C, especially maintaining a high capacity of 162 mAh g -1 at 5 A g -1 after a record-breaking 20 000 cycles. Notably, the all-vanadium symmetric pouch cells are successfully assembled for the first time based on the "rocking-chair" Mn 2+ /proton hybrid mechanism, demonstrating the practical application potential., (© 2024 Wiley‐VCH GmbH.)

Calcium ion batteries (CIBs) are a promising energy storage device due to the low redox potential of the Ca metal and the abundant reserves of the Ca element. However, the large radius and divalent nature of Ca 2+ lead to its slow ion diffusion kinetics and the lack of suitable electrode materials for Ca storage. Here, a layered structure of Na 2 Ti 3 O 7 (NTO) is presented as an anode material for nonaqueous CIBs. This NTO anode demonstrates a high discharge capacity of 165 mA h g -1 at 100 mA g -1 and a remarkable capacity retention rate of 80%, even after 2000 cycles at 500 mA g -1 , surpassing the performance of all reported intercalation-type anode materials for CIBs. The NTO transfers to layered Ca VII Na IX Ti 3 O 7 (CNTO) with intercalation of Ca 2+ and extraction of Na + during the first discharge process. Then, the CNTO undergoes the reversible insertion/extraction of Ca 2+ during subsequent cycling. Additionally, density functional theory calculations reveal that NTO possesses a rapid two-dimensional diffusion pathway for Ca 2+ . Moreover, the full CIBs based on NTO as the anode further underscore its potential for CIBs. This work presents promising anode materials for CIBs, offering opportunities to promote the development of high-performance CIBs.

Zinc powder (Zn-P) anodes have significant advantages in terms of universality and machinability compared with Zn foil anodes. However, their rough surface, which has a high surface area, intensifies the uncontrollable growth of Zn dendrites and parasitic side reactions. In this study, an anti-corrosive Zn-P-based anode with a functional layer formed from a MXene and Cu-THBQ (MXene/Cu-THBQ) heterostructure is successfully fabricated via microfluidic-assisted 3D printing. The unusual anti-corrosive and strong adsorption of Zn ions using the MXene/Cu-THBQ functional layer can effectively homogenize the Zn ion flux and inhibit the hydrogen evolution reaction (HER) during the repeated process of Zn plating/stripping, thus achieving stable Zn cycling. Consequently, a symmetric cell based on Zn-P with the MXene/Cu-THBQ anode exhibits a highly reversible cycling of 1800 h at 2 mA cm -2 /1 mAh cm -2 . Furthermore, a Zn-organic full battery matched with a 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl organic cathode riveted on graphene delivers a high reversible capacity and maintains a long cycle life., (© 2023 Wiley-VCH GmbH.)