Cathode electrolyte interphase (CEI) layer plays an essential role in determining the electrochemical performance of Li-ion batteries (LIBs), but the detailed mechanisms of CEI formation and ...evolution are not yet fully understood. With the pursuit of LIBs possessing a high energy density, fundamental investigations on the CEI have become increasingly important. Herein, X-ray photoelectron spectroscopy (XPS) is employed to fingerprint CEI formation and evolution on three of the most prevailing high-voltage cathodes including layered Li1.144Ni0.136Co0.136Mn0.544O2 (LR-NCM), Li2Ru0.5Mn0.5O3 (LRMO), and spinel LiNi0.5Mn1.5O4 (LNMO). The influences of crystal structure, chemical constitution and cut-off voltage on CEI composition are clarified. Among these cathodes, the spinel cathode exhibits the most stable CEI layer throughout the battery cycle. While the layered cathodes based on the 4d transition metal Ru favor CEI formation upon contacting the electrolyte. Most importantly, anionic redox reaction (ARR) activation at high voltages is verified to dominate CEI evolution in subsequent cycles. The distinct CEI behaviors in diverse cathodes can be attributed to a series of entangled processes, including electrolyte/Li salt decomposition, CEI component dissociation and dissociated CEI species redeposition. Based on these findings, rational guidelines are provided for the interface design of high-voltage LIBs.
Nickel‐rich layered materials LiNi1‐x‐yMnxCoyO2 are promising candidates for high‐energy‐density lithium‐ion battery cathodes. Unfortunately, they suffer from capacity fading upon cycling, especially ...with high‐voltage charging. It is critical to have a mechanistic understanding of such fade. Herein, synchrotron‐based techniques (including scattering, spectroscopy, and microcopy) and finite element analysis are utilized to understand the LiNi0.6Mn0.2Co0.2O2 material from structural, chemical, morphological, and mechanical points of view. The lattice structural changes are shown to be relatively reversible during cycling, even when 4.9 V charging is applied. However, local disorder and strain are induced by high‐voltage charging. Nano‐resolution 3D transmission X‐ray microscopy data analyzed by machine learning methodology reveal that high‐voltage charging induced significant oxidation state inhomogeneities in the cycled particles. Regions at the surface have a rock salt–type structure with lower oxidation state and build up the impedance, while regions with higher oxidization state are scattered in the bulk and are likely deactivated during cycling. In addition, the development of micro‐cracks is highly dependent on the pristine state morphology and cycling conditions. Hollow particles seem to be more robust against stress‐induced cracks than the solid ones, suggesting that morphology engineering can be effective in mitigating the crack problem in these materials.
Significant oxidation state inhomogeneities induced by high‐voltage charging are revealed for Ni‐rich Li ion battery cathode material by the machine‐learning methodology data analysis of nano‐resolution 3D transmission X‐ray microscopy. The formation and propagation of micro‐cracks are proven to be dependent on the morphology of secondary particles and cycling conditions.
Flexible sensors have been tremendously attractive in wearable electronics, soft robots and human-machine interaction devices. In this work, conductive silicon rubber (CSR) filled with ...silver-coated-glass fiber (AGF) and carbon fiber (CF) was embedded into polydimethylsiloxane (PDMS) matrix to fabricate a flexible strain sensor (FSS) in a 3D-printing (3DP) process. It was found that the addition of CF and plasticizer synergistically formed a support-structure which guaranteed the CSR to be extruded out easily in the 3DP process. The printed FSS demonstrated its highly stable properties with a gauge factor (GF) of 8–10 at different strain rate, the coincident resistance recovery process in cyclic load of different strain, as well as the stable durability with monotonous peak in 600 strain-release cycles. Furthermore, it was able to distinguish a superimposed load at frequencies of 1/12 Hz and 1/36 Hz with aids of Fast Fourier Transformation (FFT) analysis. Migrating evolution of AGFs in a stretched CSR was observed to further explore and paraphrase the mechanism of resistance response and the high GF of the FSS. The printed FSS was capable to monitor the movement of various joints and further distinguish a superimposed human motion, showing its potentially practical application in soft robots and wearable electronics.
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•Embedded 3D-printing process was an exquisite way to fabricate flexible strain sensor in one-step.•Synergistic effect of carbon fiber and plasticizer improved printability of conductive rubber.•Printed sensor was highly sensitive to mono-, cyclic and superimposed strain loads.•Excellent response of printed sensor to joint motion verified its application in wearable electronics.
•A newly designed GO-NH2: Higher adsorption capability than that of activated carbon.•Very quick adsorption property: More than 90% of Co(II) can be removed within 5min.•One of the highest adsorption ...capabilities of today's nanomaterials for Co(II) (116.35mg/g).•GO-NH2 membrane can remove more than 98% Co(II) from the water.
A newly designed amination graphene oxide (GO-NH2), a superior adsorption capability to that of activated carbon, was fabricated by graphene oxide (GO) combining with aromatic diazonium salt. The resultant GO-NH2 maintained a high surface area of 320m2/g. When used as an adsorbent, the GO-NH2 demonstrated a very quick adsorption property for the removal of Co(II) ions, more than 90% of Co(II) ions could be removed within 5min for dilute solutions at 0.3g/L adsorbent dose. The adsorption capability approaches 116.35mg/g, which is one of the highest capabilities of today's materials. The thermodynamic parameters calculated from temperature-dependent adsorption isotherms suggested that the Co(II) ions adsorption on GO-NH2 was a spontaneous process. Considering the superior adsorption capability, the GO-NH2 filter membrane was fabricated for the removal of Co(II) ions. Membrane filtration experiments revealed that the removal capabilities of the materials for cobalt ions depended on the membrane's thickness, flow rate and initial concentration of Co(II) ions. The highest percentage removal of Co(II) exceeds 98%, indicating that the GO-NH2 is one of the very suitable membrane materials in environmental pollution management.
All-solid-state lithium batteries have attracted widespread attention for next-generation energy storage, potentially providing enhanced safety and cycling stability. The performance of such ...batteries relies on solid electrolyte materials; hence many structures/phases are being investigated with increasing compositional complexity. Among the various solid electrolytes, lithium halides show promising ionic conductivity and cathode compatibility, however, there are no effective guidelines when moving toward complex compositions that go beyond ab-initio modeling. Here, we show that ionic potential, the ratio of charge number and ion radius, can effectively capture the key interactions within halide materials, making it possible to guide the design of the representative crystal structures. This is demonstrated by the preparation of a family of complex layered halides that combine an enhanced conductivity with a favorable isometric morphology, induced by the high configurational entropy. This work provides insights into the characteristics of complex halide phases and presents a methodology for designing solid materials.
The members of the miR-17-92 cluster are upregulated in various cancers and function as a cluster of oncogenic miRNA. Our study characterized a new function of miR-17-5p, a member of the miR-17-92 ...cluster, in regulating cell proliferation in pancreatic cancer. Our results indicate that miR-17-5p was up-regulated in pancreatic adenocarcinoma and directly targeted the retinoblastoma-like protein 2 (RBL2), a tumor suppressor belonging to the Rb family. High levels of miR-17-5p and low levels of RBL2 were associated with poor prognosis. RBL2 interacted with the transcription factor E2F4 and bound to the promoter regions of the E2F target genes. Disruption of the RBL2/E2F4 complex by miR-17-5p overexpression shifted the activity of E2F from gene repressing to gene activating, which induced cell cycle entry and proliferation. These results suggest that miR-17-5p promoted proliferation in pancreatic ductal adenocarcinoma cells (PDAC), and altered cell cycle profiles in vivo and in vitro, by disrupting the RBL2/E2F4-associated gene repressing complexes via direct targeting of RBL2. The new regulatory network, involving miR-17-5p and RBL2, emerges as a new target of PDAC treatment.
•miR-17-5p promotes pancreatic cancer proliferation by altering cell cycle profiles.•miR-17-5p directly targets the 3′UTR of RBL2.•RBL2 interacts directly with E2F4 and binds to promoter regions of the E2F target genes.•A model in which miR-17-5p disrupts RBL2/E2F4-associated gene repression by targeting RBL2 is proposed.
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•3D-SRGO, an innovative adsorbent, ultra high enhanced adsorption performance for Cd(II).•Quick adsorption property, more than 93% of Cd(II) can be removed within 20min.•High ...adsorption capacity 234.8mg/g, more higher than many reported adsorbent for Cd(II).•The membrane fabricated by 3D-SRGO can remove more than 96% Cd(II) from wastewater.•Regeneration test shows pH 0.3 acidic solution can desorb 97.23% Cd(II) from the loaded 3D-SRGO.
A novel adsorbent 3D sulfonated reduced graphene oxide (3D-SRGO) aerogel with porous structure, large surface area, excellent hydrophilicity and high adsorption capacity was developed for cadmium Cd(II) ions removal from water. Kinetic data reveal that the cadmium adsorption was rapid in the beginning followed by a slower adsorption process, nearly 93% adsorption can be achieved within 20min. The cadmium adsorption isotherm was well described by the pseudo second-order kinetic model. The calculated adsorption capacity of this adsorbent for cadmium by Langmuir model was 234.8mg/g at pH 6.0. The thermodynamic parameters indicated that the adsorption reaction of Cd(II) ions on the 3D-SRGO was a spontaneous process. XPS and FT-IR analyses reveal cation exchange process was an important mechanism for cadmium removal by the 3D-SRGO. Filtration experiments revealed that the membranes fabricated by 3D-SRGO could quickly remove Cd(II) ions from the aqueous solutions. Regeneration tests showed that HNO3 solution at pH=0.3 can desorb 97.23% cadmium from the cadmium ion-loaded 3D-SRGO. Findings of this study demonstrate the potential utility of the 3D-SRGO as a very effective adsorbent for cadmium removal from contaminated water.
Abstract
Reversible lattice oxygen redox reactions offer the potential to enhance energy density and lower battery cathode costs. However, their widespread adoption faces obstacles like substantial ...voltage hysteresis and poor stability. The current research addresses these challenges by achieving a non-hysteresis, long-term stable oxygen redox reaction in the P3-type Na
2/3
Cu
1/3
Mn
2/3
O
2
. Here we show this is accomplished by forming spin singlet states during charge and discharge. Detailed analysis, including in-situ X-ray diffraction, shows highly reversible structural changes during cycling. In addition, local CuO
6
Jahn-Teller distortions persist throughout, with dynamic Cu-O bond length variations. In-situ hard X-ray absorption and ex-situ soft X-ray absorption study, along with density function theory calculations, reveal two distinct charge compensation mechanisms at approximately 3.66 V and 3.99 V plateaus. Notably, we observe a Zhang-Rice-like singlet state during 3.99 V charging, offering an alternative charge compensation mechanism to stabilize the active oxygen redox reaction.
Lithium-rich nickel-manganese-cobalt (LirNMC) layered material is a promising cathode for lithium-ion batteries thanks to its large energy density enabled by coexisting cation and anion redox ...activities. It however suffers from a voltage decay upon cycling, urging for an in-depth understanding of the particle-level structure and chemical complexity. In this work, we investigate the Li
Ni
Mn
Co
O
particles morphologically, compositionally, and chemically in three-dimensions. While the composition is generally uniform throughout the particle, the charging induces a strong depth dependency in transition metal valence. Such a valence stratification phenomenon is attributed to the nature of oxygen redox which is very likely mostly associated with Mn. The depth-dependent chemistry could be modulated by the particles' core-multi-shell morphology, suggesting a structural-chemical interplay. These findings highlight the possibility of introducing a chemical gradient to address the oxygen-loss-induced voltage fade in LirNMC layered materials.
Background
Doxorubicin is one of the most effective chemotherapeutic drugs for breast cancer while its common drug resistance leads to poor patient prognosis and survival. Growing evidence indicate ...dynamically reorganized chromatin allows rapid access of the gene regulatory machinery to open genomic regions facilitating subsequent gene expression through direct transcription factor (TF) activation and regulatory element binding.
Methods
To better understand the regulatory network underlying doxorubicin resistance in breast cancer cells, we explored the systematic alterations of chromatin accessibility and gene expression by the assay for transposase-accessible chromatin using sequencing (ATAC-seq) in combination with RNA sequencing, followed by integrative analysis to identify potential regulators and their targets associated with differentially accessible regions (DARs) in doxorubicin-resistant MCF7 (MCF7-DR) cells.
Results
A total of 3,963 differentially expressed genes (DEGs) related to doxorubicin resistance were identified, including dramatically up-regulated
MT1E
,
GSTP1
,
LDHB
, significantly down-regulated
TFF1
,
UBB
,
DSCAM-AS1
, and histone-modifying enzyme coding genes
HDAC2
,
EZH2
,
PRMT5
, etc. By integrating with transcriptomic datasets, we identified 18,228 DARs in MCF7-DR cells compared to control, which were positively correlated with their nearest DEGs (
r
= 0.6). There were 11,686 increased chromatin-accessible regions, which were enriched in up-regulated genes related to diverse KEGG pathways, such as the cell cycle, regulation of actin cytoskeleton, signaling pathways of MAPK, PI3K/Akt and Hippo, which play essential roles in regulating cell apoptosis, proliferation, metabolism, and inflammatory responses. The 6,542 decreased chromatin-accessible regions were identified for the declined doxorubicin-associated biological processes, for instance, endocrine and insulin resistance, central carbon metabolism, signaling pathways of TGF-beta and P53. Combining data from TCGA, analyses of the DAR sequences associated with the DNA-binding motifs of significantly enriched TF families including AP-1, TEAD and FOX, indicated that the loss-function of FOXA1 might play a critical role in doxorubicin-resistant breast cancer cells (DOX-R BCCs).
Conclusion
These data exhibit the non-genetic landscape of chromatin accessibility and transcript levels in the DOX-R BCCs, and provide clear insights and resources for the detection of critical TFs and potential
cis
-regulatory elements-based putative therapeutic targets.
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