Reverse Rate Research Articles

Stationary distribution of a reaction-diffusion hepatitis B virus infection model driven by the Ornstein-Uhlenbeck process.

A reaction-diffusion hepatitis B virus (HBV) infection model based on the mean-reverting Ornstein-Uhlenbeck process is studied in this paper. We demonstrate the existence and uniqueness of the positive solution by constructing the Lyapunov function. The adequate conditions for the solution's stationary distribution were described. Last but not least, the numerical simulation demonstrated that reversion rates and noise intensity influenced the disease and that there was a stationary distribution. It was concluded that the solution tends more toward the stationary distribution, the greater the reversion rates and the smaller the noise.

ANALISIS PORTOFOLIO OPTIMAL MODEL CAPM DALAM PENGAMBILAN KEPUTUSAN INVESTASI SAHAM PADA IDXQ30

This paper aimed to analyze the optimal portfolio based on the Capital Asset Pricing Model (CAPM) method by classifying the undervalued and overvalued stocks. The population of this paper are stocks listed on IDXQ30 in the 2022-2023 period, there are 22 stocks used as research samples. This paper used IDXQ30 daily closing price, closing price of the daily Jakarta Stock Exchange Composite Index on the IDX, and Bank Indonesia's daily reference interest rate or the BI-7 Day Reverse Repo Rate. The results of this paper indicated that CAPM method generates 8 undervalued stocks and 14 overvalued stocks. Undervalued stocks consist of KLBF, ITMG, ASII, UNTR, BBCA, PTBA, BMRI and HRUM while overvalued stocks consist of MIKA, SIDO, HEAL, INTP, UNVR, HMSP, MNCN, CPIN, TLKM, TAPG, LSIP, ACES, SCMA and SRTG. The investment decisions are made by buying stocks that are classified as undervalued and selling stocks that are classified as overvalued.
 
 Keywords: Capital Asset Pricing Model, IDXQ30, Investment Decision, Optimal Portfolio

Catholyte Modulation and Prussian Blue/Berlin Green Redox Mediator Enabling Efficient High‐Potential Mn2+/MnO2 Reaction for Aqueous Hybrid Batteries

The use of multielectron Mn2+/MnO2 cathode reaction achieves high‐energy aqueous acid–base asymmetric hybrid batteries. However, the ion crossover through the membrane and the accumulation of unreacted MnO2 lead to serve potential and capacity decay of the cathode during cycling. Herein, the catholyte modulation using the KCl additive and the design of a Prussian blue/Berlin green (PB/BG) redox mediator on the cathode current collector are developed to promote high‐potential Mn2+/MnO2 reaction. The addition of saturated KCl greatly suppresses the ion crossover to maintain the catholyte acidity, thus enabling high‐potential Mn2+/MnO2 reaction and stable high‐voltage discharge plateau of ≈2.2 V for the hybrid battery at a prolonged cycling. The reversible MnO2 deposition is effectively improved by the PB/BG redox mediator, which contributes to significant enhancements in the reversible capacity, rate capability, and cycling stability of the cathode. Importantly, the as‐assembled hybrid battery exhibits the highest energy density of ≈260 Wh kg−1 (based on the mass of the aqueous MnCl2 catholyte and a hydrogen storage anode material) among the previously reported Mn‐based acid–base asymmetric batteries.

Thermal decomposition of 1-ethyl-3-methylimidazolium acetate

To realize the potential applications of ionic liquids as working fluids and solvents one should have knowledge about their long-term stability, which depends on their thermally initiated decomposition. However, the possible decomposition pathways are not yet known accurately. 1-Ethyl-3-methylimidazolium acetate ([C2Mim][OAc]) is widely studied and shows potential in cellulose dissolution. In this study, we investigate possible [C2Mim][OAc] decomposition pathways by combining decomposition experiments and ab initio rate constant computations. Both approaches yield activation energies around 135 kJ·mol−1, which significantly deviate from earlier TGA measurements with open surface yielding 100–110 kJ·mol−1 and are probably affected by evaporation. Our study uses an improved TGA measurement protocol with a sealed pan with a tiny hole that fosters measurement of the actual chemical process leading to mass loss. Ab initio computations of this study comprise vapor-liquid equilibria of reactants and products as well as forward and reverse reaction rate constants in the gas and liquid phase. Calculations for the gas phase closely match a first-order analysis of the experiments, but calculations for the liquid phase strongly depend on the quality of solvation modeling. The computations indicate that the SN2 pathway with an activation energy of 142–144 kJ·mol−1 dominates thermal decomposition of [C2Mim][OAc].

Spherical Shell with CNTs Network Structuring Fe-Based Alluaudite Na2+2 δ Fe2- δ (SO4 )3 Cathode and Novel Phase Transition Mechanism for Sodium-Ion Battery.

Iron-based sulfate cathodes of alluaudite Na2+2 δ Fe2- δ (SO4 )3 (NFS) in sodium-ion batteries with low cost, steady cycling performance, and high voltage are promising for grid-scale energy storage systems. However, the poor electronic conductivity and the limited understanding of the phase-evolution of precursors hinder obtaining high-rate capacity and the pure phase. Distinctive NFS@C@n%CNTs (n = 1, 2, 5, 10) sphere-shell conductive networks composite cathode materials are constructed creatively, which exhibit superior reversible capacity and rate performance. In detail, the designed NFS@C@2%CNTs cathode delivers an initial discharge capacity of 95.9 mAh g-1 at 0.05 C and up to 60 mAh g-1 at a high rate of 10 C. The full NFS@C@2%CNTs//HC cell delivers a practical operating voltage of 3.5V and mass-energy density of 140Wh kg-1 at 0.1 C, and it can also retain 67.37 mAh g-1 with a capacity retention rate of 96.4% after 200 cycles at 2 C. On the other hand, a novel combination reaction mechanism is first revealed for forming NFS from the mixtures of Na2 Fe(SO4 )2 ·nH2 O (n = 2, 4) and FeSO4 ·H2 O during the sintering process. The inspiring results would provide a novel perspective to synthesize high-performance alluaudite sulfate and analogs by aqueous methods.

Sarcopenia Transitions and Influencing Factors Among Chinese Older Adults With Multistate Markov Model

Abstract Background and Objectives Little is known about the sarcopenia transition process across different stages among Chinese community-dwelling older adults. We aimed to explore dynamic transitions of sarcopenia and its influencing factors in Chinese older adults. Research Design and Methods Data were derived from the China Health and Retirement Longitudinal Study. A total of 2856 older adults with complete data in the 2011, 2013, and 2015 waves were included in our study. Participants were categorized into 3 states: no sarcopenia, possible sarcopenia, and sarcopenia according to the Asian Working Group for Sarcopenia 2019 (AWGS 2019) criteria. Continuous-time multistate Markov model was performed to estimate the 1-year transition probabilities and the associated factors of sarcopenia transitions. The association strength was expressed as hazard ratio and 95% confidence interval. Results The progression and reversion rates between no sarcopenia and sarcopenia state were 6.01 and 9.20 per 100 person-years, respectively. The 1-year progression probability to possible sarcopenia was higher compared with the likelihood of moving to the sarcopenia state (0.127 vs 0.034). The reversion probability to no sarcopenia was also higher among those with possible sarcopenia (0.281 vs 0.157). Older age, rural living, worse cognition status, higher chronic disease numbers, and lower nutrition status measured by body mass index accelerated the sarcopenia progression. Cognition status and body mass index level were related to higher chances of reverting. Discussion and Implications Possible sarcopenia might be a critical time window to promote sarcopenia reversion. Timely interventions aimed at delaying the progression and facilitating sarcopenia recovery should focus on improving cognitive function and nutrition levels.

Cryo-annealing of Photoreduced CdS Quantum Dot-Nitrogenase MoFe Protein Complexes Reveals the Kinetic Stability of the E4(2N2H) Intermediate.

A critical step in the mechanism of N2 reduction to 2NH3 catalyzed by the enzyme nitrogenase is the reaction of the four-electron/four-proton reduced intermediate state of the active-site FeMo-cofactor (E4(4H)). This state is a junction in the catalytic mechanism, either relaxing by the reaction of a metal bound Fe-hydride with a proton forming H2 or going forward with N2 binding coupled to the reductive elimination (re) of two Fe-hydrides as H2 to form the E4(2N2H) state. E4(2N2H) can relax to E4(4H) by the oxidative addition (oa) of H2 and release of N2 or can be further reduced in a series of catalytic steps to release 2NH3. If the H2 re/oa mechanism is correct, it requires that oa of H2 be associative with E4(2N2H). In this report, we have taken advantage of CdS quantum dots in complex with MoFe protein to achieve photodriven electron delivery in the frozen state, with cryo-annealing in the dark, to reveal details of the E-state species and to test the stability of E4(2N2H). Illumination of frozen CdS:MoFe protein complexes led to formation of a population of reduced intermediates. Electron paramagnetic resonance spectroscopy identified E-state signals including E2 and E4(2N2H), as well as signals suggesting the formation of E6 or E8. It is shown that in the frozen state when pN2 is much greater than pH2, the E4(2N2H) state is kinetically stable, with very limited forward or reverse reaction rates. These results establish that the oa of H2 to the E4(2N2H) state follows an associative reaction mechanism.

Early-childhood linear growth faltering in low- and middle-income countries

Globally, 149 million children under 5 years of age are estimated to be stunted (length more than 2 standard deviations below international growth standards)1,2. Stunting, a form of linear growth faltering, increases the risk of illness, impaired cognitive development and mortality. Global stunting estimates rely on cross-sectional surveys, which cannot provide direct information about the timing of onset or persistence of growth faltering—a key consideration for defining critical windows to deliver preventive interventions. Here we completed a pooled analysis of longitudinal studies in low- and middle-income countries (n = 32 cohorts, 52,640 children, ages 0–24 months), allowing us to identify the typical age of onset of linear growth faltering and to investigate recurrent faltering in early life. The highest incidence of stunting onset occurred from birth to the age of 3 months, with substantially higher stunting at birth in South Asia. From 0 to 15 months, stunting reversal was rare; children who reversed their stunting status frequently relapsed, and relapse rates were substantially higher among children born stunted. Early onset and low reversal rates suggest that improving children’s linear growth will require life course interventions for women of childbearing age and a greater emphasis on interventions for children under 6 months of age.

Sodium-Bismuth-Titanium glass–ceramic network: A high capacity anode network for Na+ ion storage

This article discusses 95[35Na2O-65Bi2O3]: 5TiO2 (mol%) glass-ceramic anode material system (abbreviated as GC-NBT5.0) in order to overcome major issues with Na-ion battery technology, such as inadequate reversible capacity, rate capability, electrical conductivity, and safety. After heat treatment for different heat treating regimes, the production of intense intermediate domains Na3Bi and Na3Ti results in flexible active centers with which heavier Na+ ions may react very easily for Na+ ion storage in the glass-ceramic anode network. As evaluated at 50mA/g over a longer cycle life of up to 3000 cycles, the GC-NBT5.0-8h glass ceramic anode beats both glass anode and traditional graphite anodes with a specific discharge capacity of 801mAh/g. However, the cell design is still backed by the best electrical conductivity because of the good interfacial contact between the glass-ceramic anode and electrolyte, and the lowest cycle-dependent complex impedance characteristics (Rct and Zw), which guarantee consistent capacity retention and the highest Columbic efficiency over longer cycle durations.

Is Omalizumab Treatment Used During the COVID-19 Pandemic Effective on the Frequency and Severity of COVID-19?

Objective: The effects of drugs used in chronic spontaneous urticaria (CSU) and similar chronic dermatological diseases in COVID-19 continue to be the subject of many studies. The present study aimed to reveal the frequency and severity of COVID-19 infection in CSU patients treated with omalizumab and antihistamines.
 Materials and Methods: CSU patients who were followed up and treated with omalizumab or antihistamines were evaluated retrospectively for clinical conditions with CSU and COVID-19 during the pandemic and compared with the control group regarding the incidence and severity of COVID-19 infection. In addition, urticaria disease severity was also compared with pre-pandemic scores for the CSU group.
 Results: Real-time reverse transcription-polymerase chain reaction test positivity rate for SARS-CoV-2 was detected in 17.4%, 30.1%, and 34.8% of the patients in omalizumab, antihistamine, and control groups, respectively (p= 0.001). The disease activity scores were increased in both antihistamine and omalizumab treated compared to the pre-covid state CSU patients, while the increase was minor in patients using omalizumab. 
 Conclusion: The fact that COVID-19 infection was seen less frequent and urticaria activity scores were lower during the infection in the omalizumab group suggests that omalizumab treatment is safe and convenient to use during COVID-19 infection.

Improved thermonuclear rate of42Ti(p,γ)43V and its astrophysical implication in therpprocess

Context.Accurate42Ti(p,γ)43V reaction rates are crucial for understanding the nucleosynthesis path of the rapid capture process (rpprocess) that occurs in X-ray bursts.Aims.We aim to improve the thermonuclear rates of42Ti(p,γ)43V based on more complete resonance information and a more accurate direct component, together with the recently released nuclear masses data. We also explore the impact of the newly obtained rates on therpprocess.Methods.We reevaluated the reaction rate of42Ti(p,γ)43V by the sum of the isolated resonance contribution instead of the Hauser-Feshbach statistical model. We used a Monte Carlo method to derive the associated uncertainties of new rates. The nucleosynthesis simulations were performed via the NuGrid post-processing code ppn.Results.The new rates differ from previous estimations due to the use of a series of updated resonance parameters and a direct S factor. Compared with the previous results from the Hauser-Feshbach statistical model, which assumes compound nucleus43V with a sufficiently high-level density in the energy region of astrophysical interest, large differences exist over the entire temperature region ofrp-process interest, up to two orders of magnitude. We consistently calculated the photodisintegration rate using our new nuclear masses via the detailed balance principle, and found the discrepancies among the different reverse rates are much larger than those for the forward rate, up to ten orders of magnitude at the temperature of 108K. Using a trajectory with a peak temperature of 1.95×109K, we performed therp-process nucleosynthesis simulations to investigate the impact of the new rates. Our calculations show that the adoption of the new forward and reverse rates result in abundance variations for Sc and Ca of 128% and 49%, respectively, compared to the variations for the statistical model rates. On the other hand, the overall abundance pattern is not significantly affected. The results of using new rates also confirm that therp-process path does not bypass the isotope43V.Conclusions.Our study found that the Hauser-Feshbach statistical model is inappropriate to the reaction rate evaluation for42Ti(p,γ)43V. The adoption of the new rates confirms that the reaction path of42Ti(p,γ)43V(p,γ)44Cr(β+)44V is a key branch of therpprocess in X-ray bursts.

Reversal interest rate and macroprudential policy

Could a monetary policy loosening in a low interest rate environment have unintended recessionary effects? Using a non-linear macroeconomic model fitted to the euro area economy, we show that the effectiveness of monetary policy can decline in negative territory until it reaches an endogenous turning point, where monetary policy becomes contractionary. The framework demonstrates that the risk of hitting the rate at which the effect reverses depends on the capitalization of the banking sector. The possibility of the reversal interest rate gives rise to a novel motive for macroprudential policy. We show that macroprudential policy in the form of a countercyclical capital buffer, which prescribes the build-up of buffers in good times, substantially mitigates the probability of encountering the reversal rate and increases the effectiveness of negative interest rate policies. This new motive emphasizes the strategic complementarities between monetary policy and macroprudential policy.

Reversible Data Hiding With Hierarchical Block Variable Length Coding for Cloud Security

Reversible data hiding in encrypted images (RDHEI) can serve as a technical solution to secure data in applications that rely on cloud storage. The key features of an RDHEI scheme are reversibility, security, and data embedding rate. To enlarge the embedding rate, this paper proposes a novel RDHEI scheme based on the median edge detector (MED) and a new proposed hierarchical block variable length coding (HBVLC) technique. In our scheme, the image owner first predicts the pixel values of the carrier image with MED. Then, the prediction error array is sliced into bit-planes and encoded plane by plane. By leveraging the inherent features of the prediction error bit-planes, the image owner adaptively decomposes a bit-plane into blocks of different hierarchical levels based on its local smoothness and encodes the blocks with a variable length coding method. As a result, the carrier image is efficiently compressed to provide spare room for data embedding. The encoded carrier image is then processed with the conventional steps of an RDHEI technique. Experimental results show that the proposed scheme not only can restore the secret data and the carrier image without loss but also outperforms state-of-the-art methods in the embedding rate for images with various features.

543 Is It the End of Hartmann’s Procedure for Perforated Diverticulitis with Peritonitis? an Updated Systematic Review and Meta-Analysis

Abstract Aim Hartmann’s procedure is the standard technique in the management of perforated diverticulitis. However, many recent studies showed that primary resection and anastomosis have better outcomes. Our aim is to compare HP’s outcomes versus PRA for Hinchey III and IV acute diverticulitis. Method PUBMED, Scopus, and Web of science were searched from inception to September 2022 for all studies comparing the outcomes of HP versus RPA for perforated diverticulitis with peritonitis and a systematic review and meta-analysis were done. Results 29 studies with a total of 4314 participants were included in our study. The pooled results of the included studies showed a remarkable decrease in mortality after PRA (Mortality, RR = 1.38, 95% CI = 1.09-1.73, P = 0.007). However, PRA is associated with a slight increase in the incidence of leakage (Leakage, RR = 0.40, 95% CI = 0.16-1.01, P = 0.05). Nevertheless, no difference in the overall incidence of complications between the two surgeries including SSI, wound dehiscence, bleeding, ileus and reoperation. (Overall incidence of complications, RR = 1.01, 95% CI = 0.84-1.21, P = 0.95). However, PRA is associated with shorter hospital stays but longer operative time. Moreover, those who had PRA with ileostomy had a higher stoma closure rate in comparison to HP (Closure rate, RR = 0.63, 95% CI = 0.49-0.81, P = 0.0003). Conclusions With a lower incidence of mortality, equal rates of complication and higher stoma reversal rates, RPA offers an excellent alternative to HP for perforated diverticulitis with purulent or feculent peritonitis.

Carbon-Coated Sodium Vanadium Phosphate Nanocomposites as Efficient Cathode Materials for Sodium-Ion Batteries and Capacitors

Sodium vanadium phosphate (Na3V2(PO4)3) with continuous carbon-coating (NVP/C) has been regarded as one of the most promising cathode materials for sodium-ion batteries (SIBs) owing to the three-dimensional sodium superionic conductor (NASICON) structure for fast sodium-ion migrations, high theoretical energy density (ca. 400 Wh/ kg), and good thermal stability (450°C). In this study, NVP/C nanoparticles (NPs) were successfully synthesized by employing ascorbic acid as the reductant and carbon source simultaneously, followed by calcination at 750°C in an argon atmosphere. The NVP/C NPs possessed great crystallinity, high purity, size of 100-200 nm, coated carbon layer of 5-10 nm, and carbon amounts of 8.5 wt. % were confirmed through the X-ray diffractometer, transmission electron microscope, and thermogravimetric analyzer, respectively. The remarkable reversible capacity (75 mAh/g at 0.1 C), rate capability (62 mAh/g at 2 C), and capacity retention (~100% after 1,000 cycles at 1 C) were delivered from the NVP/C half-cell. Encouraged by these impressive results, the asymmetric sodium-ion capacitors (SICs) consisted of the NVP/C cathode, free-standing hydrogel-derived hierarchical porous activated carbon (H-HPAC) anode, and organic electrolyte were also assembled to explore the electrochemical performances. As revealed, excellent rate capabilities were also achieved, i.e., 44 mAh/g at 0.45 A/gNVP and 28 mAh/g at 4.5 A/gNVP. Accordingly, the NVP/C NPs synthesized in the present study are reasonably believed to serve as potential cathode materials for SIBs and SICs. Figure 1

The Growth Hormone Deficiency (GHD) Reversal Trial: effect on final height of discontinuation versus continuation of growth hormone treatment in pubertal children with isolated GHD—a non-inferiority Randomised Controlled Trial (RCT)

Background Growth hormone deficiency (GHD) is the commonest endocrine cause of short stature and may occur in isolation (I-GHD) or combined with other pituitary hormone deficiencies. Around 500 children are diagnosed with GHD every year in the UK, of whom 75% have I-GHD. Growth hormone (GH) therapy improves growth in children with GHD, with the goal of achieving a normal final height (FH). GH therapy is given as daily injections until adult FH is reached. However, in many children with I-GHD their condition reverses, with a normal peak GH detected in 64–82% when re-tested at FH. Therefore, at some point between diagnosis and FH, I-GHD must have reversed, possibly due to increase in sex hormones during puberty. Despite increasing evidence for frequent I-GHD reversal, daily GH injections are traditionally continued until FH is achieved.Methods/designEvidence suggests that I-GHD children who re-test normal in early puberty reach a FH comparable to that of children without GHD. The GHD Reversal study will include 138 children from routine endocrine clinics in twelve UK and five Austrian centres with I-GHD (original peak GH < 6.7 mcg/L) whose deficiency has reversed on early re-testing. Children will be randomised to either continue or discontinue GH therapy. This phase III, international, multicentre, open-label, randomised controlled, non-inferiority trial (including an internal pilot study) will assess whether children with early I-GHD reversal who stop GH therapy achieve non-inferior near FH SDS (primary outcome; inferiority margin 0.55 SD), target height (TH) minus near FH, HRQoL, bone health index and lipid profiles (secondary outcomes) than those continuing GH. In addition, the study will assess cost-effectiveness of GH discontinuation in the early retesting scenario.DiscussionIf this study shows that a significant proportion of children with presumed I-GHD reversal generate enough GH naturally in puberty to achieve a near FH within the target range, then this new care pathway would rapidly improve national/international practice. An assumed 50% reversal rate would provide potential UK health service cost savings of £1.8–4.6 million (€2.05–5.24 million)/year in drug costs alone. This new care pathway would also prevent children from having unnecessary daily GH injections and consequent exposure to potential adverse effects.Trial registrationEudraCT number: 2020-001006-39

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.

Retracted: Clinical Study on Long-Term Sinus Reversion Rate and Left Atrial Function Recovery of Mitral Valve Disease with Atrial Fibrillation under Modified Surgical Radiofrequency Ablation.

[This retracts the article DOI: 10.1155/2021/5667364.].

Prognostic analysis of thermal interface material effects on anisotropic heat transfer characteristics and state of health of a 21700 cylindrical lithium-ion battery module

In this study, a semi-empirical computational heat transfer model has been developed to simulate anisotropic thermal characteristics in nickel-rich rechargeable 21700 lithium-ion battery modules with thermal interface materials. A set of conservation equations were developed and numerically solved using a finite-volume-based computational fluid dynamics technique. Experimental measurements of direct current internal resistance, temperature-dependent open circuit potential, and electrochemical impedance were conducted to obtain thermal and electrical data prior to the development of battery heat generation and performance aging models. Detailed reversible and irreversible heat generation rates in battery modeling could be fully addressed and evaluated from the experimental data for post-extensive numerical analysis. After validating the developed battery models against measured experimental data, further numerical analyses were performed to evaluate the effect of thermal interface materials on the battery module temperatures and the state of health. Numerical results showed that the cooling performance of the battery module was improved by reducing interfacial thermal contact resistances after the thermal interfacing application. Moreover, it was found that the parallel thermal conductivity of the interfacing materials to bottom cooling channels is primarily related to the uniform temperature distribution of the battery module, whereas the vertical thermal conductivity is rather associated with maximum temperature. These features are clearly apparent with increased coolant flow rate and thermal interfacing thickness. Lastly, the state of health of the battery module can be enhanced with improved temperature uniformity and decreased maximum temperature of the module when the thermal interfacing materials are employed.

Post-Substitution Modulated Robust Sodium Layered Oxides.

Sodium layered oxides feature in high capacity and diverse composition, however, are plagued by various issues including limited kinetics and interfacial instability with residual alkali. Conventional substitution/doping and heterogeneous coating are promising to tackle the problems of bulk and surface, respectively, but normally insufficient to address both. Herein, a post-substitution strategy is proposed to modify primary sodium-layered-oxide particles that can simultaneously deal with bulk and surficial issues. As a typical example, post Ti-substitution for O3-NaNi1/3 Fe1/3 Mn1/3 O2 is successfully performed by adjusting thermodynamic driving force, resulting in depth-controllable Ti infusion from surface to bulk, as proved by energy dispersive spectroscopy maps collected at the cross-section. Residual alkali species are efficiently diminished and benefited from the surface-to-bulk osmotic reaction, significantly improving Coulombic efficiency. Moreover, remarkable enhancements in reversible capacity (135mAhg-1 at C/10), rate capability (74% retention at 5C), and long-term cycling stability (80% retention after 300 cycles at 2C) are achieved by manipulating gradient-like Ti distribution in a primary particle that brings with increased kinetics and strengthened interfacial stability, surpassing those given by rough heterotic coating and homogeneous Ti-substitution. Such post-substitution is expected to provide a universal strategy to modify primary layered-oxide particles for developing advanced cathode materials of SIBs.