New Insights into Electrochemical Lithiation/Delithiation Mechanism of α‑MoO₃ Nanobelt by in Situ Transmission Electron Microscopy

The α-MoO3 nanobelt has great potential for application as anode of lithium ion batteries (LIBs) because of its high capacity and unique one-dimensional layer structure. However, its fundmental electrochemical failure mechanism during first lithiation/delithiation process is still unclear. Here, we constructed an electrochemical setup within α-MoO3 nanobelt anode inside a transmission electron microscope to observe in situ the mircostructure evolution during cycles. Upon first lithiation, the α-MoO3 nanobelt converted into numerous Mo nanograins within the Li2O matrix, with an obvious size expansion. Interestingly, α-MoO3 nanobelt was found to undergo a two-stage delithiation process. Mo nanograins were first transformed into crystalline Li1.66Mo0.66O2 along with the disappearance of Li2O and size shrink, followed by the conversion to amorphous Li2MoO3. This irreversible phase conversion should be responsible for the large capacity loss in first cycle. In addition, a fully reversile phase conversion between crystalline Mo and amorphous Li2MoO3 was revealed accompanying the formation and disapperance of the Li2O layer during the subsequent cycles. Our experiments provide direct evidence to deeply understand the distinctive electrochemical lithiation/delithiation behaviors of α-MoO3 nanobelt, shedding light onto the development of α-MoO3 anode for LIBs

New Insights into Electrochemical Lithiation/Delithiation Mechanism of α‑MoO₃ Nanobelt by in Situ Transmission Electron Microscopy

The α-MoO3 nanobelt has great potential for application as anode of lithium ion batteries (LIBs) because of its high capacity and unique one-dimensional layer structure. However, its fundmental electrochemical failure mechanism during first lithiation/delithiation process is still unclear. Here, we constructed an electrochemical setup within α-MoO3 nanobelt anode inside a transmission electron microscope to observe in situ the mircostructure evolution during cycles. Upon first lithiation, the α-MoO3 nanobelt converted into numerous Mo nanograins within the Li2O matrix, with an obvious size expansion. Interestingly, α-MoO3 nanobelt was found to undergo a two-stage delithiation process. Mo nanograins were first transformed into crystalline Li1.66Mo0.66O2 along with the disappearance of Li2O and size shrink, followed by the conversion to amorphous Li2MoO3. This irreversible phase conversion should be responsible for the large capacity loss in first cycle. In addition, a fully reversile phase conversion between crystalline Mo and amorphous Li2MoO3 was revealed accompanying the formation and disapperance of the Li2O layer during the subsequent cycles. Our experiments provide direct evidence to deeply understand the distinctive electrochemical lithiation/delithiation behaviors of α-MoO3 nanobelt, shedding light onto the development of α-MoO3 anode for LIBs

New Insights into Electrochemical Lithiation/Delithiation Mechanism of α‑MoO₃ Nanobelt by in Situ Transmission Electron Microscopy

The α-MoO₃ nanobelt has great potential for application as anode of lithium ion batteries (LIBs) because of its high capacity and unique one-dimensional layer structure. However, its fundmental electrochemical failure mechanism during first lithiation/delithiation process is still unclear. Here, we constructed an electrochemical setup within α-MoO₃ nanobelt anode inside a transmission electron microscope to observe in situ the mircostructure evolution during cycles. Upon first lithiation, the α-MoO₃ nanobelt converted into numerous Mo nanograins within the Li₂O matrix, with an obvious size expansion. Interestingly, α-MoO₃ nanobelt was found to undergo a two-stage delithiation process. Mo nanograins were first transformed into crystalline Li_1.66Mo_0.66O₂ along with the disappearance of Li₂O and size shrink, followed by the conversion to amorphous Li₂MoO₃. This irreversible phase conversion should be responsible for the large capacity loss in first cycle. In addition, a fully reversile phase conversion between crystalline Mo and amorphous Li₂MoO₃ was revealed accompanying the formation and disapperance of the Li₂O layer during the subsequent cycles. Our experiments provide direct evidence to deeply understand the distinctive electrochemical lithiation/delithiation behaviors of α-MoO₃ nanobelt, shedding light onto the development of α-MoO₃ anode for LIBs

Novel Interface in CuAg Nanostructure Induced by Size Effect

Bimetallic Janus nanostructures (JNs) have been revealed to be valuable materials because they have unique intermetallic interfaces that enable their potential use in a range of applications. However, with the increasing miniaturization of electronic devices, particle sizes influence the structure and orientation of these heterointerfaces, which plays a significant role in their application. Our in situ annealing experiments with high-resolution transmission electron microscopy have shown that for particle sizes in the sub-10 nm range, CuAg JNs preferentially show a Cu(100)/Ag(100) interface, differing from the larger CuAg JNs, where the Cu(111)/Ag(111) interface is favored. We discuss a feasible atomic motion mechanism to explain the effect of particle size on the formation of different heterointerfaces. Our results reveal the presence of a novel sub-10 nm heterostructure with a unique Cu(100)/Ag(100) interface and also provide crucial insights into understanding the role of particle size in interfacial evolution during thermal annealing of heterostructures

Isobutylhydroxyamides from Sichuan Pepper and Their Protective Activity on PC12 Cells Damaged by Corticosterone

The pericarp of <i>Zanthoxylum bungeanum</i> Maxim., commonly known as Sichuan pepper, is a widely used spice to remove fishy odor and add palatable taste. A phytochemical investigation of the 95% ethanol extract of Sichuan pepper resulted in the isolation of 21 isobutylhydroxyamides, including 8 new ones named ZP-amides G–N, among which the chiral resolution of racemic ZP-amide A and ZP-amide B was successfully accomplished. The protective activity on corticosterone-treated PC12 cells of the isolated isobutylhydroxyamides was also evaluated. The new compounds <b>3</b>–<b>5</b> and the known compounds <b>1</b>, <b>1a</b>, <b>2</b>, <b>2a</b>, <b>11</b>, and <b>15</b> improved the survival rate of PC12 cells. The bioactivity studies disclosed the potential of Sichuan pepper to be developed as new neuroprotective functional food

Visualizing Facets Asymmetry Induced Directional Movement of Cadmium Chloride Nanomotor

Nanomotors in solution have many potential applications. However, it has been a significant challenge to realize the directional motion of nanomotors. Here, we report cadmium chloride tetrahydrate (CdCl2·4H2O) nanomotors with remarkable directional movement under electron beam irradiation. Using in situ liquid phase transmission electron microscopy, we show that the CdCl2·4H2O nanoparticle with asymmetric surface facets moves through the liquid with the flat end in the direction of motion. As the nanomotor morphology changes, the speed of movement also changes. Finite element simulation of the electric field and fluid velocity distribution around the nanomotor assists the understanding of ionic self-diffusiophoresis as a driving force for the nanomotor movement; the nanomotor generates its own local ion concentration gradient due to different chemical reactivities on different facets

Visualizing Facets Asymmetry Induced Directional Movement of Cadmium Chloride Nanomotor

Nanomotors in solution have many potential applications. However, it has been a significant challenge to realize the directional motion of nanomotors. Here, we report cadmium chloride tetrahydrate (CdCl2·4H2O) nanomotors with remarkable directional movement under electron beam irradiation. Using in situ liquid phase transmission electron microscopy, we show that the CdCl2·4H2O nanoparticle with asymmetric surface facets moves through the liquid with the flat end in the direction of motion. As the nanomotor morphology changes, the speed of movement also changes. Finite element simulation of the electric field and fluid velocity distribution around the nanomotor assists the understanding of ionic self-diffusiophoresis as a driving force for the nanomotor movement; the nanomotor generates its own local ion concentration gradient due to different chemical reactivities on different facets

Understanding the Ensemble of Growth Behaviors of Sub-10-nm Silver Nanorods Using <i>in Situ</i> Liquid Cell Transmission Electron Microscopy

Desirable properties of nanomaterials in practical applications are directly associated with their specific size and morphology. Nanostructure growth behaviors in the synthesis process should be therefore studied for controlling and adjusting optimal configurations. In this work, the multistep liquid-phase growth mechanism of sub-10 nm silver nanorods in diameter is revealed using in situ liquid cell transmission electron microscopy. We observed that small-sized silver nanoparticles were first formed from precursor solution by monomer attachment. Then, larger nanoparticle building blocks were generated by nanoparticle attachment. Subsequently, shape-directed attachment growth of nanoparticle building blocks resulted in the formation of silver nanorods. During these processes, two approaching nanoparticles jumped to contact and coalesced into a dimer nanoparticle. When another particle approached the dimer nanoparticle, the nanoparticle chain would be formed by the end-to-end attachment. After the chain straightened, accompanied by mass redistribution and lattice rotation, single-crystalline silver nanorods dominated by {111} planes were finally produced. We attributed the jump-to-contact of individual nanoparticles and end-to-end attachment of nanorods in liquid to the formation of transient paired nanoparticle surfaces associated with the hydration layers and the weaker hydration force at the nanorod ends. Understanding these growth trajectories provide important fundamental insight connecting sub-10-nm crystal morphologies to the development of kinetically stabilized surface features

Understanding the Ensemble of Growth Behaviors of Sub-10-nm Silver Nanorods Using <i>in Situ</i> Liquid Cell Transmission Electron Microscopy

Desirable properties of nanomaterials in practical applications are directly associated with their specific size and morphology. Nanostructure growth behaviors in the synthesis process should be therefore studied for controlling and adjusting optimal configurations. In this work, the multistep liquid-phase growth mechanism of sub-10 nm silver nanorods in diameter is revealed using in situ liquid cell transmission electron microscopy. We observed that small-sized silver nanoparticles were first formed from precursor solution by monomer attachment. Then, larger nanoparticle building blocks were generated by nanoparticle attachment. Subsequently, shape-directed attachment growth of nanoparticle building blocks resulted in the formation of silver nanorods. During these processes, two approaching nanoparticles jumped to contact and coalesced into a dimer nanoparticle. When another particle approached the dimer nanoparticle, the nanoparticle chain would be formed by the end-to-end attachment. After the chain straightened, accompanied by mass redistribution and lattice rotation, single-crystalline silver nanorods dominated by {111} planes were finally produced. We attributed the jump-to-contact of individual nanoparticles and end-to-end attachment of nanorods in liquid to the formation of transient paired nanoparticle surfaces associated with the hydration layers and the weaker hydration force at the nanorod ends. Understanding these growth trajectories provide important fundamental insight connecting sub-10-nm crystal morphologies to the development of kinetically stabilized surface features

Visualizing Facets Asymmetry Induced Directional Movement of Cadmium Chloride Nanomotor

Nanomotors in solution have many potential applications. However, it has been a significant challenge to realize the directional motion of nanomotors. Here, we report cadmium chloride tetrahydrate (CdCl2·4H2O) nanomotors with remarkable directional movement under electron beam irradiation. Using in situ liquid phase transmission electron microscopy, we show that the CdCl2·4H2O nanoparticle with asymmetric surface facets moves through the liquid with the flat end in the direction of motion. As the nanomotor morphology changes, the speed of movement also changes. Finite element simulation of the electric field and fluid velocity distribution around the nanomotor assists the understanding of ionic self-diffusiophoresis as a driving force for the nanomotor movement; the nanomotor generates its own local ion concentration gradient due to different chemical reactivities on different facets