Nanoscale Visualization of Lithium Plating/Stripping Tuned by On-site Formed Solid Electrolyte Interphase in All-Solid-State Lithium-Metal Batteries.

The interfacial processes, mainly the lithium (Li) plating/stripping and the evolution of the solid electrolyte interphase (SEI), are directly related to the performance of all-solid-state Li-metal batteries (ASSLBs). However, the complex processes at solid-solid interfaces are embedded under the solid-state electrolyte, making it challenging to analyze the dynamic processes in real time. Here, using in situ electrochemical atomic force microscopy and optical microscopy, we directly visualized the Li plating/stripping/replating behavior, and measured the morphological and mechanical properties of the on-site formed SEI at nanoscale. Li spheres plating/stripping/replating at the argyrodite solid electrolyte (Li6 PS5 Cl)/Li electrode interface is coupled with the formation/wrinkling/inflating of the SEI on its surface. Combined with in situ X-ray photoelectron spectroscopy, details of the stepwise formation and physicochemical properties of SEI on the Li spheres are obtained. It is shown that higher operation rates can decrease the uniformity of the Li+ -conducting networks in the SEI and worsen Li plating/stripping reversibility. By regulating the applied current rates, uniform nucleation and reversible plating/stripping processes can be achieved, leading to the extension of the cycling life. The in situ analysis of the on-site formed SEI at solid-solid interfaces provides the correlation between the interfacial evolution and the electrochemical performance in ASSLBs.

Impact of the Local Environment on Li Ion Transport in Inorganic Components of Solid Electrolyte Interphases.

The spontaneously formed passivation layer, the solid electrolyte interphase (SEI) between the electrode and electrolyte, is crucial to the performance and durability of Li ion batteries. However, the Li ion transport mechanism in the major inorganic components of the SEI (Li2CO3 and LiF) is still unclear. Particularly, whether introducing an amorphous environment is beneficial for improving the Li ion diffusivity is under debate. Here, we investigate the Li ion diffusion mechanism in amorphous LiF and Li2CO3 via machine-learning-potential-assisted molecular dynamics simulations. Our results show that the Li ion diffusivity in LiF at room temperature cannot be accurately captured by the Arrhenius extrapolation from the high temperature (>600 K) diffusivities (difference of ∼2 orders of magnitude). We reveal that the spontaneous formation of Li-F regular tetrahedrons at low temperatures (<500 K) leads to an extremely low Li ion diffusivity, suggesting that designing an amorphous bulk LiF-based SEI cannot help with the Li ion transport. We further show the critical role of Li2CO3 in suppressing the Li-F regular tetrahedron formation when these two components of SEIs are mixed. Overall, our work provides atomic insights into the impact of the local environment on Li ion diffusion in the major SEI components and suggests that suppressing the formation of large-sized bulk-phase LiF might be critical to improve battery performance.

A Low-Strain Cathode by sp-Carbon Induced Conversion in Multi-Level Structure of Graphdiyne.

A multi-level architecture formed alternatively by the conformal graphdiyne (GDY) and CuS is well engineered for Li-free cathode. Such a proof-of-concept architecture efficiently integrates the advantages of GDY and produces new functional heterojunctions (sp-C-S-Cu hybridization bond). The layer-by-layer 2D confinement effect successfully avoids structural collapse, the selective transport inhibits the shuttling of active components, and the interfacial sp-C-S-Cu hybridization bond significantly regulates the phase conversion reaction. Such new sp-C-S-Cu hybridization of GDY greatly improves the reaction dynamics and reversibility, and the cathode delivers an energy density of 934 Wh kg-1 and an unattenuated lifespan of 3000 cycles at 1 C. Our results indicate that the GDY-based interface strategy will greatly promote the efficient utilization of the conversion-type cathodes.

Chemical-Mechanical Robustness of Single-Crystalline Ni-Rich Cathode Enabled by Surface Atomic Arrangement Control.

Layered transition metal oxide cathodes have been one of the dominant cathodes for lithium-ion batteries with efficient Li+ intercalation chemistry. However, limited by the weak layered interaction and unstable surface, mechanical and chemical failure plagues their electrochemical performance, especially for Ni-rich cathodes. Here, adopting a simultaneous elemental-structural atomic arrangement control based on the intrinsic Ni-Co-Mn system, the surface role is intensively investigated. Within the invariant oxygen sublattice of the crystal, a robust surface with the synergistic concentration gradient and layered-spinel intertwined structure is constructed on the model single-crystalline Ni-rich cathode. With mechanical strain dissipation and chemical erosion suppression, the cathode exhibits an impressive capacity retention of 82 % even at the harsh 60 °C after 150 cycles at 1 C. This work highlights the coupling effect of structure and composition on the chemical-mechanical properties, and the concept will spur more researches on the cathodes that share the same sublattice.

Revealing the High Salt Concentration Manipulated Evolution Mechanism on the Lithium Anode in Quasi-Solid-State Lithium-Sulfur Batteries.

Lithium-sulfur batteries are promising candidates of energy storage devices. Both adjusting salt/solvent ratio and applying quasi-solid-state electrolytes are regarded as effective strategies to improve the lithium (Li) anode performance. However, reaction mechanisms and interfacial properties in quasi-solid-state lithium-sulfur (QSSLS) batteries with high salt concentration are not clear. Here we utilize in-situ characterizations and molecular dynamics simulations to unravel aforesaid mysteries, and construct relationships of electrolyte structure, interfacial behaviour and performance. The generation mechanism, formation process, and mechanical/chemical/electrochemical properties of the anion-derived solid electrolyte interphase (SEI) are deeply explored. Li deposition uniformity and dissolution reversibility are further tuned by the sustainable SEI. These straightforward evidences and deepgoing studies would guide the electrolyte design and interfacial engineering of QSSLS batteries.

Catalpol suppresses proliferation and facilitates apoptosis of OVCAR-3 ovarian cancer cells through upregulating microRNA-200 and downregulating MMP-2 expression.

Catalpol is expected to possess diverse pharmacological actions including anti-cancer, anti-inflammatory and hypoglycemic properties. Matrix metalloproteinase-2 (MMP-2) is closely related to the pathogenesis of ovarian cancer. In addition, microRNA-200 (miR-200) can modulate phenotype, proliferation, infiltration and transfer of various tumors. Here, OVCAR-3 cells were employed to investigate whether the effect of catalpol (25, 50 and 100 µg/mL) promoted apoptosis of ovarian cancer cells and to explore the potential mechanisms. Our results demonstrate that catalpol could remarkably reduce the proliferation and accelerate the apoptosis of OVCAR-3 cells. Interestingly, our findings show that catalpol treatment significantly decreased the MMP-2 protein level and increased the miR-200 expression level in OVCAR-3 cells. Further, microRNA-200 was shown to regulate the protein expression of MMP-2 in OVCAR-3 cells. It is concluded that catalpol suppressed cellular proliferation and accelerated apoptosis in OVCAR-3 ovarian cancer cells via promoting microRNA-200 expression levels and restraining MMP-2 signaling.

Mirk/Dyrk1B mediates G0/G1 to S phase cell cycle progression and cell survival involving MAPK/ERK signaling in human cancer cells.

BACKGROUND: Mirk/Dyrk1B contributes to G0 arrest by destabilization of cyclin D1 and stabilization of p27kip1 to maintain the viability of quiescent human cancer cells, and it could be negatively regulated by mitogenic-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) signaling. This study was performed to investigate the effect of Mirk/Dyrk1B on cell cycle and survival of human cancer cells involving MAPK/ERK signaling. METHODS: The correlations between Mirk/Dyrk1B expression and active ERK1/2 detected by western blot in both ovarian cancer and non-small cell lung cancer (NSCLC) cells were analyzed by simple regression. Mirk/Dyrk1B unique phosphopeptides with sites associated with Mirk/Dyrk1B protein were isolated and quantitated by liquid chromatography coupled to tandem mass/mass spectrometry (LC-MS/MS) proteomics analysis. The human cancer cells were treated with small interfering RNAs (siRNAs) and/or U0126, an inhibitor of MEK for indicated duration, followed by investigating the alterations of cell cycle and apoptosis as well as related proteins examined by flow cytometry and Western blot, respectively. RESULTS: Our study demonstrated the widely expressed Mirk/Dyrk1B proteins in the human cancer cells were positively correlated with the levels of activated ERK1/2. Moreover, Mirk/Dyrk1B protein expressions consistent with the tyrosine autophosphorylated levels in the human cancer cells were increased by U0126 or growth factor-depleted culture. Conversely, knockdown of Mirk/Dyrk1B by siRNA led to up-regulated activation of c-Raf-MEK-ERK1/2 pathway and subsequent changes in cell cycle proteins (cyclin D1, p27kip1), accompanied by increased growth rate and cells from G0/G1 into S of cell cycle which could be blocked by U0126 in a dose-dependent manner, indicating Mirk/Dyrk1B may sequester MAPK/ERK pathway, and vice versa. Whereas, combined Mirk siRNA and U0126 induced cell apoptosis in the human cancer cells. CONCLUSIONS: These data together show that Mirk/Dyrk1B mediates cell cycle and survival via interacting with MAPK/ERK signals and simultaneous inhibition of both pathways may be a novel therapeutic target for human cancer.

In Situ Insight into the Interfacial Dynamics in "Water-in-Salt" Electrolyte-Based Aqueous Zinc Batteries.

Water-in-salt (WIS) electrolyte is considered as one of most promising systems for aqueous zinc batteries (AZBs) due to its dendrite-free plating/stripping with nearly 100% Coulombic efficiency. However, the understanding of the interfacial mechanisms remains elusive, which is crucial for further improvements in battery performance. Herein, the interfacial processes of solid electrolyte interphase (SEI) formation and subsequent Zn plating/stripping are monitored by in situ atomic force microscopy and in situ optical microscopy. The live formation of uniform and compact LiF-rich SEI in WIS systems could induce the uniform hexagonal Zn deposition with preferential orientation growth in the (002) crystal plane, showing excellent plating/stripping reversibility. In contrast, the SEI formed in 1 m zinc bis(trifluoromethylsulfonyl)imide (Zn(TFSI)2 ) is uneven and rich in inert ZnO, adversely triggering the dendrite propagation and successive "dead" Zn accumulation in repeated deposition/dissolution cycles. This work provides an in-depth understanding of the relationship between SEI evolution and Zn-deposited behaviors in AZBs, possibly stimulating more research on rational composition design and structural optimization of solid/liquid interface for advanced rechargeable aqueous multivalent-ion batteries.

Leptin induces functional activation of cyclooxygenase-2 through JAK2/STAT3, MAPK/ERK, and PI3K/AKT pathways in human endometrial cancer cells.

Hyperleptinemia is a common feature of obese women who have a higher risk of endometrial cancer than women with normal weights, and epidemiologic studies have suggested a correlation between obesity and endometrial carcinoma. Therefore, understanding of the molecular mechanism involved in leptin signaling transduction is important in endometrial cancer prevention and treatment. In this study, both isoforms of the leptin receptor (Ob-R), the long form (Ob-Rb) and short form (Ob-Ra), were detected as being expressed in six endometrial cancer cell lines with various differentiation status by western blotting, and Ob-Ra was found to be more abundant than Ob-Rb in these cells. Moreover, the expressions of both isoforms were inversely correlated with histoprognostic grading. We also showed that leptin stimulated cell proliferation and induced activations of signal transducers and activators of transcription 3 (STAT3), extracellular signal-regulated kinase (ERK1/2), AKT, and cyclooxygenase (COX)-2 in endometrial cancer cells dose-dependently by [(3)H] thymidine incorporation assay and western blotting. Leptin-stimulation resulted in increased expression of COX-2 mRNA and prostaglandin E2 (PGE2) production of endometrial cancer cells by reverse transcription-polymerase chain reaction and enzyme immunoassay, respectively, which was effectively blocked by pharmacological inhibitors of Janus tyrosine kinase 2 (JAK2), AG490; of mitogen-activated protein kinase (MAPK) kinase, U0126; of phosphatidylinositol 3-kinase (PI3K), LY294002; and of COX-2, NS398. These results suggest that leptin promotes cell proliferation of endometrial cancer cells via the aforementioned multiple signal-transduction pathways. Leptin-induced functional activation of COX-2 is JAK2/STAT3-, MAPK/ERK-, and PI3K/AKT-dependent, indicating that COX-2 may be a critical factor of endometrial carcinogenesis in obesity.