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1. High Voltage Irreversibilities in NASICON Na _3+y V _2–y Mg _y (PO ₄ ) ₃ Cathodes

   https://doi.org/10.1021/acs.chemmater.5c01434  

   Gonzalez-Correa, Eliovardo; Mazumder, Madhulika; Kumar, Keshav; Ghosh, Subham; Senguttuvan, Premkumar; Clément, Raphaële J (August 2025, Chemistry of Materials)

   Na3+yV2-yMgy(PO4)3 (0 ≤ y ≤ 1) NASICON compounds, thanks to their relative simplicity and the presence of a single redox-active species, are of interest for understanding the function and limitations of more complex, mixed transition metal NASICON-type Na-ion cathodes. Partial Mg substitution for V in Na3+yV2-yMgy(PO4)3 leads to a gradual transition from a two-phase to a solid solution Na (de)intercalation mechanism during electrochemical cycling. When cycled over a narrow voltage window (3.8 – 2.75 V vs. Na+/Na0), these cathodes exhibit good structural and electrochemical reversibility, leading to a high capacity retention. Yet, when the upper cutoff voltage is increased from 3.8 V to 4.2 V, significant irreversibilities arise, accompanied by a notable evolution of the electrochemical profiles during the first cycle. We focus here on the y = 0.5 and 1 compounds and use a combination of electrochemical testing, advanced characterization, and first principles density functional theory calculations to investigate the redox and structural processes taking place at high potentials. In-situ and ex-situ X-ray diffraction, and 23Na and 31P solid-state NMR reveal bulk structural rearrangements, at least partly caused by Na extraction from Na(1) sites. For the y = 1 cathode, an irreversible phase transition leads to a change in the symmetry of the crystal structure from rhombohedral to monoclinic. For both compounds, substantial distortions of the VO6 octahedra and irreversible changes to the local structure are observed using X-ray absorption spectroscopy during high voltage cycling, but our 51V NMR results show no evidence for V migration. Instead, first principles nudged elastic band calculations suggest low energy migration pathways for Mg2+ into vacant face-sharing Na(1) sites at high states of charge. These findings are consistent with the significant evolution of the electrochemical profile during the first cycle, voltage hysteresis, and subsequent rapid capacity decay. More broadly, these results could suggest similar structural rearrangements (e.g., Mn migration) in related V- and Mn-containing NASICON cathodes, which also show poor reversibility when cycled up to high potentials. 

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2. Sn-Segregation Behavior and Its Suppression in Ge _1–y Sn _y Semiconductor Alloys with y > 0.20

   https://doi.org/10.1021/acs.cgd.5c01532  

   Ringwala, Dhruve A; Roldan, Manuel A; Samarasingha, Nuwanjula S; Zollner, Stefan; Menéndez, José; Kouvetakis, John (April 2026, Crystal Growth & Design)
3. Crystal Growth and Physical Properties of Hybrid CoSn–YCo ₆ Ge ₆ Structure Type Ln _x Co ₃ (Ge _1–y Sn _y ) ₃ (Ln = Y, Gd)

   https://doi.org/10.1021/acs.inorgchem.3c02172  

   Bravo, Moisés; McCandless, Gregory T.; Baumbach, Ryan E.; Wang, Yaojia; Ali, Mazhar N.; Chan, Julia Y. (November 2023, Inorganic Chemistry)
4. Phase Diagrams and Piezoelectric Properties of Wurtzite Al _1−x−y Sc _x Gd _y N Heterostructural Alloys

   https://doi.org/10.1002/advs.202520641  

   Martin, Julia L; Lee, Cheng‐Wei; Bernstein, Nate SP; Nguyen, Thi; Bryan, Ande; Cooper, Eli; Mangum, John S; Bauers, Sage R; Zakutayev, Andriy; Yazawa, Keisuke; et al (January 2026, Advanced Science)

   ABSTRACT Ternary nitride alloys based on wurtzite AlN are a promising platform to realize functional materials, particularly ferroelectrics and optical emitters, that can smoothly integrate with conventional microelectronics. Here, a strategic design is presented to enable multifunctional materials by substituting multiple elements into AlN to create quaternary nitride alloys. By combining computational predictions and combinatorial thin film synthesis, the phase diagram of these quaternary Al–Sc–Gd–N alloys (or pseudo‐ternary heterostructural AlN–ScN–GdN alloys) is successfully predicted as a function of effective temperature, and we experimentally grow thin films for the first time. It is revealed that crystallizes in a wurtzite‐derived structure for , consistent with the calculated phase diagram. The computational investigation explores whether co‐substitution induces cooperative effects on these alloys' piezoelectric and ferroelectric properties, finding that it is beneficial for reducing the polarization switching barrier. We calculate that thin films should display ferroelectric switching. This is supported by our experimental measurements of a high optical bandgap, enhanced piezoelectric coefficient, and a change in the calculated polarization switching mechanism, and we achieve preliminary ferroelectric switching that experimentally realizes the prediction. Overall, our work sets the foundation toward quaternary wurtzite‐nitride‐based multifunctional materials, including piezoelectrics, ferroelectrics, and possibly even multiferroics. 

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5. (V _1–y Mo _y ) ₂ C T _x MXene Nanosheets as Electrocatalysts for Hydrogen Evolution

   https://doi.org/10.1021/acsanm.4c06029  

   Snyder, Rose M; Nguyen, Thao; Bhatt, Prajna; Riaz, Aysha A; Thakur, Pardeep K; Lee, Tien-Lin; Regoutz, Anna; Jones, Anne K; Birkel, Christina S (January 2025, ACS Applied Nano Materials)