2024 New's Items

Effect of solid-electrolyte pellet density on failure of solid-state batteries

Diallo MS
Shi T
Zhang Y
Peng X
Shozib I
Wang Y
2024

Despite the potentially higher energy density and improved safety of solid-state batteries (SSBs) relative to Li-ion batteries, failure due to Li-filament penetration of the solid electrolyte and subsequent short circuit remains a critical issue. Herein, we show that Li-filament growth is suppressed in solid-electrolyte pellets with a relative density beyond ~95%. Below this threshold value, however, the battery shorts more easily as the density increases due to faster Li-filament growth within the percolating pores in the pellet. The microstructural properties (e.g., pore size,...

Selective formation of metastable polymorphs in solid-state synthesis

Zeng Y
Szymanski NJ
He T
Jun K
Gallington LC
Huo H
2024
Metastable polymorphs often result from the interplay between thermodynamics and kinetics. Despite advances in predictive synthesis for solution-based techniques, there remains a lack of methods to design solid-state reactions targeting metastable materials. Here, we introduce a theoretical framework to predict and control polymorph selectivity in solid-state reactions. This framework presents reaction energy as a rarely used handle for polymorph selection, which influences the role of surface energy in promoting the nucleation of metastable phases. Through in situ characterization and...

Engineering interfacial polarization switching in van der Waals multilayers

Van Winkle M
Dowlatshahi N
Khaloo N
Iyer M
Craig IM
Dhall R
Taniguchi T
Watanabe K
Bediako DK
2024

In conventional ferroelectric materials, polarization is an intrinsic property limited by bulk crystallographic structure and symmetry. Recently, it has been demonstrated that polar order can also be accessed using inherently non-polar van der Waals materials through layer-by-layer assembly into heterostructures, wherein interfacial interactions can generate spontaneous, switchable polarization. Here we show that deliberate interlayer rotations in multilayer van der Waals heterostructures modulate both the spatial ordering and switching dynamics of polar domains. The engendered tunability...

Optimal thermodynamic conditions to minimize kinetic by-products in aqueous materials synthesis

Wang Z
Sun Y
Cruse K
Zeng Y
Fei Y
Liu Z
2024

Phase diagrams offer substantial predictive power for materials synthesis by identifying the stability regions of target phases. However, thermodynamic phase diagrams do not offer explicit information regarding the kinetic competitiveness of undesired by-product phases. Here we propose a quantitative and computable thermodynamic metric to identify synthesis conditions under which the propensity to form kinetically competing by-products is minimized. We hypothesize that thermodynamic competition is minimized when the difference in free energy between a target phase and the minimal energy of...

The Microscopic Mechanism of Lithiation and Delithiation in the Ag/C Buffer Layer for Anode-Free Solid-State Batteries

Xie F
Diallo MS
Kim H
Tu QH
Ceder G
2024

Lithium metal solid-state batteries (LMSSBs) have demonstrated their high energy density and cycling performance at high current densities in an anode-free architecture, featuring a thin Ag/C composite buffer layer (BL) between the current collector (CC) and the solid electrolyte (SE). This study explains the microscopic mechanism of the Ag/C BL by using first-principles atomistic and continuum modeling. It is shown that Ag effectively acts as a homogeneous solid-solution beyond AgLi2.32 and maintains a positive potential even at AgLi25 during lithiation. Key...

Angle between DNA linker and nucleosome core particle regulates array compaction revealed by individual-particle cryo-electron tomography

Zhang M
Díaz-Celis C
Liu J
Tao J
Ashby PD
Bustamante C
Ren G
2024

The conformational dynamics of nucleosome arrays generate a diverse spectrum of microscopic states, posing challenges to their structural determination. Leveraging cryogenic electron tomography (cryo-ET), we determine the three-dimensional (3D) structures of individual mononucleosomes and arrays comprising di-, tri-, and tetranucleosomes. By slowing the rate of condensation through a reduction in ionic strength, we probe the intra-array structural transitions that precede inter-array interactions and liquid droplet formation. Under these conditions, the arrays exhibite irregular zig-zag...

Local atomic stacking and symmetry in twisted graphene trilayers

Craig IM
Van Winkle M
Groschner C
Zhang K
Dowlatshahi N
Zhu Z
Taniguchi T
Watanabe K
Griffin SM
Bediako DK
2024

Moiré superlattices formed by twisting trilayers of graphene are a useful model for studying correlated electron behaviour and offer several advantages over their formative bilayer analogues, including a more diverse collection of correlated phases and more robust superconductivity. Spontaneous structural relaxation alters the behaviour of moiré superlattices considerably and has been suggested to play an important role in the relative stability of superconductivity in trilayers. Here we use an interferometric four-dimensional scanning transmission electron microscopy approach to directly...

Scanning electrochemical probe microscopy investigation of two-dimensional materials

Pelumi A
Romo J
Zhang K
Maroo S
Bediako DK
Yu Y
2024

Research interests in two-dimensional (2D) materials have seen exponential growth owing to their unique and fascinating properties. The highly exposed lattice planes coupled with tunable electronic states of 2D materials have created manifold opportunities in the design of new platforms for energy conversion and sensing applications. Still, challenges in understanding the electrochemical (EC) characteristics of these materials arise from the complexity of both intrinsic and extrinsic heterogeneities that can obscure structure–activity correlations. Scanning EC probe microscopic...

Considerations for extracting moiré-level strain from dark field intensities in transmission electron microscopy

Craig IM
Van Winkle M
Ophus C
Bediako DK
2024

Bragg interferometry (BI) is an imaging technique based on four-dimensional scanning transmission electron microscopy (4D-STEM) wherein the intensities of select overlapping Bragg disks are fit or more qualitatively analyzed in the context of simple trigonometric equations to determine local stacking order. In 4D-STEM based approaches, the collection of full diffraction patterns at each real-space position of the scanning probe allows the use of precise virtual apertures much smaller and more variable in shape than those used in conventional dark field imaging such that even buried...

Good plasmons in a bad metal

Ruta FL
Shao Y
Acharya S
Mu A
Jo NH
Ryu SH
Balatsky D
Pashov D
Analytis JG
Cava RJ
Shekhter A
McDonald RD
Zuo H
Lee H
Wu W
2024

Correlated materials may exhibit unusually high resistivity increasing linearly in temperature, breaking through the Mott-Ioffe-Regel bound, above which coherent quasiparticles are destroyed. The fate of collective charge excitations, or plasmons, in these systems is a subject of debate. Several studies suggest plasmons are overdamped while others detect unrenormalized plasmons. Here, we present direct optical images of low-loss hyperbolic plasmon polaritons (HPPs) in the correlated van der Waals metal MoOCl2. HPPs are plasmon-photon modes that waveguide through extremely anisotropic media...