High Reversible Rate Research Articles

Longitudinal Patterns and Predictors of Cognitive Impairment Classification Stability.

Classifications such as Cognitive Impairment, No Dementia (CIND) are thought to represent the transitory, pre-clinical phase of dementia. However, increasing research demonstrates that CIND represents a nonlinear, unstable entity that does not always lead to imminent dementia. The present study utilizes a longitudinal repeated measures design to gain a thorough understanding of CIND classification stability patterns and identify predictors of future stability. The objectives were to i) explore patterns of longitudinal stability in cognitive status across multiple assessments and ii) investigate whether select baseline variables could predict 6-year CIND stability patterns. Participants (N = 259) included older adults (aged 65-90years) from Project MIND, a six-year longitudinal repeated measures design in which participants were classified as either normal cognition (NC) or CIND at each annual assessment. A latent transition analysis approach was adapted in order to identify and characterize transitions in CIND status across annual assessments. Participants were classified as either Stable NC, Stable CIND, Progressers, Reverters, or Fluctuaters. Multinomial logistic regression was employed to test whether baseline predictors were associated with cognitive status stability patterns. The sample demonstrated high rates of reversion and fluctuation in CIND status across annual assessments. Additionally, premorbid IQ and CIND severity (i.e., single vs. multi-domain impairment) at baseline were significantly associated with select stability outcomes. CIND status was unstable for several years following baseline assessment and cognitive reserve may delay or protect against demonstrable cognitive impairment. Further, consideration of cognitive impairment severity at the time of initial classification may improve CIND classifications.

Hierarchical mesoporous Co3O4@C-N nanostructure rods derived from a metal-organic framework as high-performance anode for lithium-ion battery

A uniform hierarchical mesoporous Co3O4@C-N nanostructure rods were in situ fabricated successfully by developing a facile one-step strategy. Cobalt-based metal organic framework [Co3(ndc)(HCOO)3(μ-OH)(H2O)]n with special Co chine constructed framework structure treated as a precursor directly pyrolyzed in a mixed atmosphere of argon and oxygen (95:5) at 500 °C for 2 h. According to the XRD pattern, SEM, TEM, EDS mapping images and XPS spectrum analysis, the well-defined hierarchical mesoporous Co3O4@C-N nanostructure rods showed pure Co3O4 phase, are assembled from a large number of core–shell structured Co3O4@C-N spherical particles with an ultrasmall and uniform size (∼8 nm) which were further connected by N doped carbon net to form nanostructure rods. Using as anode material for lithium-ion batteries, these hierarchical mesoporous Co3O4@C-N nanostructure rods exhibit excellent electrochemical performance with high reversible capacity, rate capability and good cycling stability. They maintained a reversible specific capacity of more than 1000 mAh/g at 100 mA/g, and the discharge specific capacities at the 5 current density of 0.1, 0.2, 0.5, 1, 2, and 5 A/g reached 1123, 1094, 1044, 979, 879 and 688 mAh/g, respectively.

In Situ Defect Engineering in Carbon by Atomic Self-Activation to Boost the Accessible Low-Voltage Insertion for Advanced Potassium-Ion Full-Cells.

Enhancing the low-potential capacity of anode materials is significant in boosting the operating voltage of full-cells and constructing high energy-density energy storage devices. Graphitic carbons exhibit outstanding low-potential potassium storage performance, but show a low K+ diffusion kinetics. Herein, in situ defect engineering in graphitic nanocarbon is achieved by an atomic self-activation strategy to boost the accessible low-voltage insertion. Graphitic carbon layers grow on nanoscale-nickel to form the graphitic nanosphere with short-range ordered microcrystalline due to nickel graphitization catalyst. Meanwhile, the widely distributed K+ in the precursor induces the activation of surrounding carbon atoms to in situ generate carbon vacancies as channels. The graphite microcrystals with defect channels realize reversible K+ intercalation at low-potential and accessible ion diffusion kinetics, contributing to high reversible capacity (209mAhg-1 at 0.05Ag-1 under 0.8V) and rate capacity (103.2mAhg-1 at 1Ag-1). The full-cell with Prussian blue cathode and graphitic nanocarbon anode maintains an obvious working platform at ca. 3.0V. This work provides a strategy for the in situ design of carbon anode materials and gives insights into the potassium storage mechanism at low-potential for high-performance full-cells.

Prevalence and Molecular Characterization of Vancomycin Variable Enterococcus faecium Isolated From Clinical Specimens.

Vancomycin variable Enterococcus (VVE) bacteria are phenotypically susceptible to vancomycin, but they harbor the vanA gene. We aimed to ascertain the prevalence of VVE among clinically isolated vancomycin-susceptible Enterococcus faecium (VSE) isolates, as well as elucidate the molecular characteristics of the vanA gene cluster within these isolates. Notably, we investigated the prevalence and structure of the vanA gene cluster of VVE. Between June 2021 and May 2022, we collected consecutive, non-duplicated vancomycin-susceptible Enterococcus faecium (VSE) samples. Real-time PCR was performed to detect the presence of vanA, vanB, and vanC. Overlapping PCR with sequencing and whole-genome sequencing were performed for structural analysis. Sequence types (STs) were determined by multilocus sequence typing. Exposure testing was performed to assess the ability of the isolates to acquire vancomycin resistance. Among 282 VSE isolates tested, 20 isolates (7.1%) were VVE. Among them, 17 isolates had partial deletions in the IS1216 or IS1542 sequences in vanS (N=10), vanR (N=5), or vanH (N=2). All VVE isolates belonged to the CC17 complex and comprised five STs, namely ST17 (40.0%), ST1421 (25.0%), ST80 (25.0%), ST787 (5.0%), and ST981 (5.0%). Most isolates were related to three hospital-associated clones (ST17, ST1421, and ST80). After vancomycin exposure, 18 of the 20 VVEs acquired vancomycin resistance. Considering the high reversion rate, detecting VVE by screening VSE for vanA is critical for appropriate treatment and infection control.

Mechanically robust and conductive Ti5Te4/P@C composite materials as promising lithium-ion battery anodes

An urgent need has emerged to develop lithium-ion battery anodes that exhibit high reversible capacity and rate performance surpassing carbonaceous materials. Si-based composites have been investigated extensively. However, in this study, we explored another potential alloy anode consisting of Te and phosphorus without Si. Herein, we present a novel composite material, Ti5Te4/P@C, as an anode for lithium-ion batteries (LIBs). Tellurium, which exhibits good electrical conductivity and high volumetric capacity, and red phosphorus, which exhibits high theoretical capacity, were selected as potential anode materials. To overcome the common drawbacks of the two materials, including the vigorous expansion of volume, electrochemically inactive materials, such as titanium and carbon, were introduced as matrix buffers. Te, Ti, red phosphorus, and C were synthesized using a three-step high energy ball milling (HEBM) technique, that is, stepwise synthesis of (1) Ti and Te, (2) red phosphorus, and (3) carbon. The developed Ti5Te4/P@C composites revealed that the introduction of red P led to the generation of additional pure Te in the Ti5Te4/P@C composites, which was owing to the different binding interactions between Ti, Te, and red P, as confirmed by DFT calculations. Among the developed Ti5Te4/P@C anodes, Ti5Te4/P(30 wt%)@C exhibited outstanding cyclability and high rate performance (440 mAh g−1 at 300 mA g−1 after 500 cycles). To confirm the electrochemical responses and Li+ ion diffusion mechanisms, CV and GITT analyses were performed. Based on the electrochemical characteristics, the superior electrochemical performance of the Ti5Te4/P@C anodes can be ascribed to the well-defined composite structure, including the high electrical conductivity of Te, high theoretical capacity of red P, and effective buffering agents of Ti as a mechanical supporter and conductive C, which enable a pseudocapacitive response, providing better reversibility. Therefore, the Ti5Te4/P@C composite materials are viable anodes for high-performance LIBs.

Chemically bonded MXene/SnSe2 composite with special structural transformation as a high-performance anode for lithium and potassium ions battery

Sn-C bonding coupled MXene/SnSe2 composite with SnSe2 nanosheets vertically coating on the MXene surface was prepared successfully by the solvothermal method, in which MXene matrix etched separately by HF and LiF/HCl was used to explore the improving effect on the electrochemical performance of SnSe2. It is found that MXene etched by HF acid shows more obvious accordion-like structure with larger layer spacing, and its composite with SnSe2 demonstrates better lithium and potassium storage properties. When employed as potassium-ion batteries (PIBs) anode, MXene/SnSe2 electrode can deliver a reversible capacity of 222.8 mAh·g−1 till 300 cycles at the current density of 200 mA·g−1. As an anode for lithium-ion batteries (LIBs), MXene/SnSe2 could provide high reversible capacity (515.6 mAh·g−1 after 300 cycles at 200 mA·g−1) and rate capacity (1015.1 mAh·g−1 at 500 mA·g−1 and 496.2 mAh·g−1 at 5000 mA·g−1). Even at 2000 mA·g−1, the capacity of MXene/SnSe2 can be maintained at 322.6 mAh·g−1 after 500 cycles. Further analysis by ex-situ SEM finds that the MXene/SnSe2 electrode undergoes structural reconstruction at the high current density of 2000 mA·g−1. In the first few cycles, SnSe2 nanosheets are changed into a network structure and then in-situ pulverized into many small nanoparticles, all which immerged on MXene surface and between layers. Although MXene/SnSe2 electrode experiences structural transformation, it retains apparent layered structure. This provides a fast channel for electrons and ions migration, resulting in higher Li+ diffusion rate and diffusion-controlled storage capacity. It is believed that the work could be acted as a reference for design composite with MXene and used for anode as well as other materials.

Bifunctional electrocatalytic hybrid heterostructures for polysulfide anchoring/conversion for a stable lithium-sulfur battery.

In situ phase engineering of transition metal dichalcogenides (TMDs) with controlled sulfur vacancies offers a promising strategy for superior-performance lithium-sulfur (Li-S) batteries. Herein, we demonstrate a bifunctional approach by designing a sulfur host material using 1T-MoS2/MoO3 heterostructures grown directly on carbon nanopot-resembling designer structures (CMS). The metallic phase (1T-MoS2) with MoO3 synergistically contributes to exceptional electronic transport, increased interlayer spacing, and more electrochemically active sites across its basal plane. Carbon nanopot structures and sulfur vacancies within the TMDs act as anchoring sites for lithium polysulfides (LiPSs). Additionally, the specifically phase-engineered 2D heterostructure promotes their efficient conversion into the electrochemically favorable Li2S phase. This dual functionality is expected to significantly improve the rate capability and cycle life stability of Li-S batteries. This translates to a high reversible rate capacity of 1205 mA h g-1 at a current density of 0.2 A g-1. The sulfur-loaded CMS nanostructure shows an excellent cycling life with a decay rate of only 0.078% over 1100 cycles at 1 A g-1, underscoring the effectiveness of the in situ phase engineering approach for creating a stable Li-S battery.

Permanent Shape Reconfiguration and Locally Reversible Actuation of a Carbon Nanotube/Ethylene Vinyl Acetate Copolymer Composite by Constructing a Dynamic Cross-Linked Network.

Given the rapid developments in modern devices, there is an urgent need for shape-memory polymer composites (SMPCs) in soft robots and other fields. However, it remains a challenge to endow SMPCs with both a reconfigurable permanent shape and a locally reversible shape transformation. Herein, a dynamic cross-linked network was facilely constructed in carbon nanotube/ethylene vinyl acetate copolymer (CNT/EVA) composites by designing the molecular structure of EVA. The CNT/EVA composite with 0.05 wt % CNT realized a steady-state temperature of ∼75 °C under 0.11 W/cm2 light intensity, which gave rise to remote actuation behavior. The dynamic cross-linked network along with a wide melting temperature offered opportunities for chemical and physical programming, thus realizing the achievement of the programmable three-dimensional (3D) structure and locally reversible actuation. Specifically, the CNT/EVA composite exhibited a superior permanent shape reconfiguration by activating the dynamic cross-linked network at 140 °C. The composite also showed a high reversible deformation rate of 11.1%. These features endowed the composites with the capability of transformation to 3D structure as well as locally reversible actuation performance. This work provides an attractive guideline for the future design of SMPCs with sophisticated structures and actuation capability.

Mild Cognitive Impairment – Prospects for Prognosis and Management

The term mild cognitive impairment (MCI) has traditionally been used to refer to a transitional period between normal cognitive function and clinically probable Alzheimer’s disease (AD). Many studies report high reversion rates, however, with some 30% to 50% of those diagnosed with MCI reverting to “normal” cognition at subsequent follow-up. The detection of differentiable predisposing factors, reflected in the dichotomy between the annual reversion rate to normal cognition and the conversion rate to dementia, indicates that there are modifiable factors that may be contributing to cognitive decline. The clinical prospect for dementia and the presence of these predisposing factors have together made a strong case for early diagnosis and therapeutic intervention. Current efforts seek to identify tools capable of resolving the causal ambiguities inherent in MCI and to develop therapeutic avenues addressing such underlying aspects before long lasting and irreversible cognitive loss. This review explores three arenas for which there is especial promise for determining and modulating prognosis: in the diagnostic realm, novel neuroimaging procedures and biomarkers and, in the domain of therapy, network based non-invasive neurostimulation therapies. Particular examples include novel structural and dynamical MRI procedures for assessing connectivity and its alterations during disease, inflammation and miRNA markers, and non-invasive procedures for rehabilitating deteriorating brain functions. The advances occurring in these select areas indicate that the determination of MCI’s multi-etiology is a realistic goal that can ground prognosis assessment and therapeutic outcome.

Core-shell structured Si@Cu nanoparticles segregated in graphene-carbon nanotube networks enable high reversible capacity and rate capability of anode for lithium-ion batteries

The volume expansion of Si electrodes and the poor conductivity of Si as well as the repeated rupture of solid electrolyte interface (SEI) lead to the rapid capacity decay of Si-based anode Li-ion batteries. The rational design of anode materials for the above problems is considered an effective solution. In this work, core-shell structured Si@Cu nanoparticles segregated in graphene-carbon nanotube networks (Si@Cu/CNT/rGO) is constructed by one-step hybrid and reduction self-assembly strategy. First, metallic copper was coated on silicon nanoparticles to improve the reaction kinetics of the cell during operation. The flexible reduced graphene oxide and rigid carbon nanotube are designed as a network structure for increasing the electrical conductivity and mechanical strength of the electrode material. This design not only provides sufficient buffering space for the volume change during cell operation, but also improves the electron migration effect of the composite Si@Cu/CNT/rGO. Thanks to this design, the composite electrode maintains a high lithium storage capacity of 1915.5 mAh/g (130 cycles) and 1486.7 mAh/g (200 cycles) after charging and discharging at 100 mA g−1 and 1000 mA g−1, respectively.

Carbon confined GeO2 hollow spheres for stable rechargeable Na ion batteries.

Germanium (Ge) based nanomaterials are regarded as promising high-capacity anode materials for Na ion batteries, but suffer fast capacity fading problems caused by the alloying/de-alloying reactions of Na-Ge. Herein, we report a new method for preparing highly dispersed GeO2 by using molecular-level ionic liquids (ILs) as carbon sources. In the obtained GeO2@C composite material, GeO2 exhibits hollow spherical morphology and is uniformly distributed in the carbon matrix. The as-prepared GeO2@C exhibits improved Na ion storage performances including high reversible capacity (577 mA h g-1 at 0.1C), rate property (270 mA h g-1 at 3C), and high capacity retention (82.3% after 500 cycles). The improved electrochemical performance could be attributed to the unique nanostructure of GeO2@C, the synergistic effect between GeO2 hollow spheres and the carbon matrix ensures the anode material effectively alleviates the volume expansion and the particle agglomeration problems.

Reversible and irreversible stimuli-responsive chromism of a square-planar platinum(ii) salt.

A new simple Pt(ii) terpyridyl salt that shows reversible response towards acetonitrile and irreversible response towards methanol has been reported, accompanied with the colorimetric/luminescent changing from red to yellow. Experimentally and theoretically, the spectroscopic change derives from the hydrogen bonds between crystal water in the Pt(ii) terpyridyl salt and external organic molecules, and the different strength of hydrogen bond leads either reversible or irreversible stimuli-response. Furthermore, this Pt(ii) terpyridyl salt has been on one hand applied as a probe for sensing acetonitrile in water solution, with high selectivity, good reversibility, proper sensitivity and fast response rate, and on the other hand as advanced anticounterfeiting materials. The current study provides a new approach to acquire and design either reversible or irreversible stimuli-responsive luminescent materials.

Adaptation dynamics between copy-number and point mutations.

Together, copy-number and point mutations form the basis for most evolutionary novelty, through the process of gene duplication and divergence. While a plethora of genomic data reveals the long-term fate of diverging coding sequences and their cis-regulatory elements, little is known about the early dynamics around the duplication event itself. In microorganisms, selection for increased gene expression often drives the expansion of gene copy-number mutations, which serves as a crude adaptation, prior to divergence through refining point mutations. Using a simple synthetic genetic reporter system that can distinguish between copy-number and point mutations, we study their early and transient adaptive dynamics in real time in Escherichia coli. We find two qualitatively different routes of adaptation, depending on the level of functional improvement needed. In conditions of high gene expression demand, the two mutation types occur as a combination. However, under low gene expression demand, copy-number and point mutations are mutually exclusive; here, owing to their higher frequency, adaptation is dominated by copy-number mutations, in a process we term amplification hindrance. Ultimately, due to high reversal rates and pleiotropic cost, copy-number mutations may not only serve as a crude and transient adaptation, but also constrain sequence divergence over evolutionary time scales.

Earth's Paleomagnetic Field and its Changes Through Time

Paleomagnetic data is the only way to access the behavior of the geomagnetic field of internal origin through geological time. Therefore, the complete description of the paleosecular variation (PSV) is fundamental for unraveling the evolution of the Earth's core. Modeling of PSV relies on observing the fluctuations in the direction and intensity of the field on the surface, the evaluation of the paleomagnetic data dispersion in different times and situations of low and high reversal rates, the kinematics of the virtual poles during reversals, and other aspects. Magneto-cyclostratigraphy is a powerful tool to constrain the age of sedimentary formations, and the recognition of patterns of magnetic variation represents a breakthrough in the development of cyclostratigraphy. This paper reviews some of the contributions to the subject of the Laboratory of Paleomagnetism at Instituto de Astronomia, Geofísica e Ciências Atmosféricas the University of São Paulo.

3D heterojunction assembled via interlayer-expanded MoSe2 nanosheets anchored on N-doped branched TiO2@C nanofibers as superior anode material for sodium-ion batteries

High-performance sodium-ion batteries (SIBs) are highly expected in the field of large-scale static energy storage due to the low expenditure and abundant sodium resource. However, the sodium storage performance of anode materials for SIBs has suffered from the foot-dragging reaction kinetics arising from large-size Na+ during intercalation/deintercalation, which imposes more stringent requirements on the morphology and structure of the potential anode electrodes. Herein, we successfully designed and synthesized a three-dimensional (3D) heterojunction as anode material for SIBs, which assembled by interlayer-expanded MoSe2 nanosheets perpendicularly anchored on the nitrogen-doped branched TiO2 @C nanofibers (MoSe2 @NBT@CNFs). Not only does the branched TiO2 @C nanofibers suppress the severe self-aggregation of MoSe2 nanosheets but also buffer the volume expansion during the cycling process. Moreover, an expanded interlamellar distance of MoSe2 nanosheets accelerate sodium ion diffusion, and strong chemical interactions between MoSe2 nanosheets and carbon nanofibers are conducive to improve the charge-transfer kinetics and reinforce the structural durability. As might be expected, the MoSe2 @NBT@CNFs anode can deliver excellent cycling performance with high reversibility (315.2 mAh g1 after 800 cycles at 2 A g1) and remarkable rate capability (194.2 mAh g1 at 30 A g1). The rational design strategy could offer guidance for developing high-performance metal chalcogenide-based electrode materials for SIBs.

High Sulfur-doped hollow carbon sphere with multicavity for high-performance Potassium-ion hybrid capacitors.

S doping is an effective strategy to improve the potassium-ion storage performance of carbon-based materials. However, due to the large atomic radius of S and poor thermal stability, it is challenging to synthesize carbon materials with high sulfur content by solid-phase transformation. In this work, we designed a multi-cavity structure that can confine the molten S during heat treatment and make it fully react, then achieving high S doping (7.6 at. %). As we known, S doping can also effectively increase the active sites of carbon materials to obtain higher capacity. In addition, through different ex/in-situ characterizations and DFT calculations, we confirmed that the S atoms can effectively expand the interlayer spacing of carbon, which facilitates the intercalation/deintercalation reaction of K+, thereby significantly improving the rate performance. Therefore, benefiting from the effect of S-doping, the sample exhibits high reversible specific capacity (401.0 mAh g-1 at 0.1 A/g) and rate performance (167.2 mAh g-1 at 5 A/g). The as-assembled K+ hybrid capacitor delivers both high energy density and power density (138.5Whkg-1 and 7692.5Wkg-1, respectively). This work provides a new approach to design S content carbon-based materials for high performance K+ storage.

Open versus laparoscopic Hartmann's procedure: a systematic review and meta-analysis.

Hartmann's procedure is traditionally performed in emergency situations where single-step procedures with immediate anastomosis may be unsafe. However, it can be associated with significant morbidity and low colostomy reversal rate. Whilst randomised controlled trials and a Cochrane review have reported strong evidence of laparoscopic over open colectomies, no such reviews have been performed for Hartmann's procedure. Hence, this paper aims to summarise the existing evidence to determine the efficacy of laparoscopic Hartmann's procedure over its open counterpart. Embase, Medline and Cochrane databases were searched from inception to 15 November 2020 for keywords relating to 'laparoscopy' and 'Hartmann' using strict inclusion and exclusion criteria. Odds ratio was estimated for dichotomous outcomes and weighted mean difference was estimated for continuous outcomes. From the 836 articles yielded from the search strategy, 12 articles were selected for meta-analysis. Pooled analysis revealed that laparoscopic Hartmann's procedure (LHP) allows for a shorter length of stay, and a lower risk of overall surgical site infections and superficial surgical site infections. There was no significant difference in other outcomes. Single-arm analysis of LHP also showed an unprecedented high colostomy reversal rate of over 80%. In clinically suitable patients, laparoscopic Hartmann's procedure has benefits over open Hartmann's procedure. Despite the selection bias of single-arm studies, LHP has reported a high stoma reversal rate of over 80%. Future well-controlled studies should be done to affirm the findings.

Centralizing the Umbilicus in Abdominoplasty: Eccentric versus Concentric Fascial Plication in Addition to Medializing at the Skin.

The umbilicus is often not a midline structure. Centralization of the umbilicus during an abdominoplasty is routinely performed at the level of the skin; however, this is associated with a high rate of postoperative reversion. The authors propose using an eccentric fascial plication centered on the true midline to maintain postoperative centralization of the umbilicus in addition to correction at the skin level. A retrospective study was conducted of all patients between 2015 and 2019 who underwent abdominoplasty with either skin only (concentric plication) or fascial (eccentric plication) umbilical centralization. The Fisher exact test and t test were used to compare the two groups and assess differences in rates of umbilical reversion. A total of 71 patients were included in the study; the majority of patients were women [ n = 69 (97%)] and White [ n = 50 (70%)]. There were 28 (39%) patients who underwent concentric plication, and 43 (61%) had eccentric plication. Mean body mass index in the concentric and eccentric groups was 32 kg/m 2 and 28.5 kg/m 2 , respectively. Average follow-up was 51.6 months for concentric plication and 27.8 months for eccentric plication. Of those who received concentric plication, 10 patients (36%) had their umbilicus revert to the preoperative position; none in the eccentric plication group reverted ( P < 0.0001). Midline placement of the umbilicus during an abdominoplasty is important in providing symmetry to optimize aesthetics. Eccentric fascial plication maintains the centralization of the umbilicus when compared with concentric fascial plication with skin-only centralization. Therapeutic, III.

High-Performance Aqueous Zinc-Ion Batteries Enabled by Binder-Free and Ultrathin V2O5-x@Graphene Aerogels with Intercalation Pseudocapacitance.

As a result of the absence of solid-state diffusion limitation, intercalation pseudocapacitance behavior is emerging as an attractive charge-storage mechanism that can greatly facilitate the ion kinetics to boost the rate capability and cycle stability of batteries; however, related research in the field of zinc-ion batteries (ZIBs) is still in the initial stage and only found in limited cathode materials. In this study, a novel V2O5-x@rGO hybrid aerogel consisting of ultrathin V2O5 nanosheets (∼1.26 nm) with abundant oxygen vacancies (Vö) and a three-dimensional (3D) graphene conductive network was specifically designed and used as a freestanding and binder-free electrode for ZIBs. As expected, the ideal microstructure of both the material and the electrode enable fast electron/ion diffusion kinetics of the electrode, which realize a typical intercalation pseudocapacitance behavior as demonstrated by the simulation calculation of cyclic voltammetry (CV), ex situ X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and first-principles density functional theory (DFT) calculation. Thanks to the elimination of solid-state diffusion limitation, the V2O5-x@rGO electrode delivers a high reversible rate capacity of 153.9 mAh g-1 at 15 A g-1 and 90.6% initial capacity retention at 0.5 A g-1 after 1050 cycles in ZIBs. The intercalation pseudocapacitance behavior is also realized in the assembled soft-pack battery, showing promising practical application prospects.

Cage-like MnSe@PPyC/rGO as superior dual anode materials in Li/Na-ions storage

Along with high reversible capacity, superior cycling and rate performances, transition metal-based materials have been considered as promising dual anode materials for lithium/sodium ion storage. However, one of the greatest challenges during the selenization process is that the as-prepared transition metal selenides with designed morphology could retain the original morphology of transition metal oxides well. To address this key issue, in this work, a cage-like MnSe@PPyC/rGO composite is successfully developed by one-step selenization/carbonization treatment with in-situ formed polypyrrole coated MnO2 nanorods and graphene oxide as precursors, which effectively preserve the original rod-like morphology and endow a conductive network. The morphology control process, composition and microstructural change have been systematically characterized with SEM, EDS, TEM, TGA, BET, XRD, and XPS. Benefited from the above composition and structure, cage-like MnSe@PPyC/rGO exhibits good rate performance (310.3 mAh/g at 3.2 A/g) and high reversible lithium storage capacity (776.9 mAh/g at 0.1 A/g after rate testing). As anode materials for SIBs, the composite demonstrates high capacity of 546.6 mAh/g at 0.2 A/g as well as outstanding rate capability and cycle stability (294.4 mAh/g after 455 cycles at 2 A/g and 194.5 mAh/g after 2000 cycles at 10 A/g). The finding provides a new avenue for the study of transition metal/carbon composites with special morphology as dual anode materials for Li/Na-ions storage.