Reverse Ion Research Articles

Synergic Origin and Evolution of TDS, Mg and Fluoride in Groundwater as Relative to Chronic Kidney Disease of Unknown Etiology (CKDu) in Sri Lanka

The rural population in the Dry Zone of Sri Lanka is largely affected by Chronic Kidney Disease of Unknown etiology (CKDu). According to the multidisciplinary research carried out so far, quality of groundwater is considered one of the possible causative factors for CKDu. Therefore, assessment of the quality of groundwater being used for drinking and its evolution mechanism is the key to identifying the linkage between CKDu and drinking water. This study aimed to perform a detailed investigation on groundwater sources using isotopic, chemical, and hydrogeological methods in the CKDu-endemic (site A) and the control area (sedimentary formation—site B) in the Malwathu Oya basin and the control areas in the Malala Oya basin (site C) selected for a systematic comparison. Our investigation shows that elevated levels of TDS, magnesium, and fluoride in the shallow groundwater affected by climatic, geochemical, and hydrogeological processes may contribute to the CKDu in the Dry Zone of Sri Lanka. All the groundwater samples analysed have exceeded the hardness threshold. Prominent Mg hardness proportion together with excess F− in the CKDu endemic area may produce nephrotoxic MgF2 complexes that may trigger renal damage. In contrast, NaF complexes in the CKDu control area leads to reduction of F− toxicity in the human body. Elevated F− and Mg2+ are found in site A, low F− and high Mg2+ in site B, and either combinations of low F− and low Mg2+, high F− and low Mg2+, or low F− with high Mg2+ in site C. TDS, hardness, Mg2+, Na+, and F− are formed with different mechanisms in the three selected areas. The primary process that regulates the evolution of groundwater types and contents in sites A and C is the weathering of silicates. Similarly, in site A, carbonate dissolution and reverse ion exchange are quite strong. Cation exchange and evaporite dissolution are more pronounced in site C. Shallow groundwaters are evapo-concentrated, hence their quality deteriorates more significantly than the deep groundwater in the CKDu endemic area. Dilution decreases the ion content in site A while evaporite dissolution increases it in site C after the rainy season. Evaporation and seawater mixing affect the quality of groundwater in site B. It is also found that a statistically significant difference exists in the F−/Na+, F−/Mg2+, and F−/Ca2+ between the endemic and control areas. Intensive rock weathering combined with desorption has added excess F− to the groundwater in site A, while cation exchange and fluorite dissolution are contributing factors in site C.

Evidence for reversible oxygen ion movement during electrical pulsing: enabler of emerging ferroelectricity in binary oxides

Ferroelectric HfO2-based materials and devices show promising potential for applications in information technology but face challenges with inadequate electrostatic control, degraded reliability, and serious variation in effective oxide thickness scaling. We demonstrate a novel interface-type switching strategy to realize ferroelectric characteristics in atomic-scale amorphous binary oxide films, which are formed in oxygen-deficient conditions by atomic layer deposition at low temperatures. This approach can avoid the shortcomings of reliability degradation and gate leakage increment in scaling polycrystalline doped HfO2-based films. Using theoretical modeling and experimental characterization, we show the following. (1) Emerging ferroelectricity exists in ultrathin oxide systems as a result of microscopic ion migration during the switching process. (2) These ferroelectric binary oxide films are governed by an interface-limited switching mechanism, which can be attributed to oxygen vacancy migration and surface defects related to electron (de)trapping. (3) Transistors featuring ultrathin amorphous dielectrics, used for non-volatile memory applications with an operating voltage reduced to ±1 V, have also been experimentally demonstrated. These findings suggest that this strategy is a promising approach to realizing next-generation complementary metal-oxide semiconductors with scalable ferroelectric materials.

Toward Decontamination in Coastal Regions: Groundwater Quality, Fluoride, Nitrate, and Human Health Risk Assessments within Multi-Aquifer Al-Hassa, Saudi Arabia

Contamination in coastal regions attributed to fluoride and nitrate cannot be disregarded, given the substantial environmental and public health issues they present worldwide. For effective decontamination, it is pivotal to identify regional pollution hotspots. This comprehensive study was performed to assess the spatial as well as indexical water quality, identify contamination sources, hotspots, and evaluate associated health risks pertaining to nitrate and fluoride in the Al-Hassa region, KSA. The physicochemical results revealed a pervasive pollution of the overall groundwater. The dominant water type was Na-Cl, indicating saltwater intrusion and reverse ion exchange impact. Spatiotemporal variations in physicochemical properties suggest diverse hydrochemical mechanisms, with geogenic factors primarily influencing groundwater chemistry. The groundwater pollution index varied between 0.8426 and 4.7172, classifying samples as moderately to very highly polluted. Similarly, the synthetic pollution index (in the range of 0.5021–4.0715) revealed that none of the samples had excellent water quality, with various degrees of pollution categories. Nitrate health quotient (HQ) values indicated chronic human health risks ranging from low to severe, with infants being the most vulnerable. Household use of nitrate-rich groundwater for showering and cleaning did not pose significant health risks. Fluoride HQ decreased with age, and children faced the highest risk of fluorosis. The hazard index (HI) yielded moderate- to high-risk values. Nitrate risks were 1.21 times higher than fluoride risks, as per average HI assessment. All samples fell into the vulnerable category based on the total hazard index (THI), with 88.89% classified as very high risk. This research provides valuable insights into groundwater quality, guiding water authorities, inhabitants, and researchers in identifying safe water sources, vulnerable regions, and human populations. The results highlight the need for appropriate treatment techniques and long-term coastal groundwater management plans.

Multifunctional Dual‐Metal‐Salt Derived Ternary Eutectic Electrolyte for Highly Reversible Zinc Ion Battery

AbstractDeep eutectic electrolytes offer opportunities for tailoring solvation structure and interface chemistry in advanced batteries, but developing deep eutectic electrolytes for high‐performance zinc ion batteries (ZIBs) remains a challenge. Herein, multifunctional dual‐metal‐salt derived ternary eutectic electrolytes (DMEEs) are designed via a supporting salt strategy for dendrite‐free and long‐lifespan ZIBs. DMEEs are constructed by zinc trifluoromethanesulfonate (Zn(OTF)2), supporting salt of lithium bis(trifluoromethanesulfonyl)imide, and neutral ligand of N‐methylacetamide. Noticeably, supporting salt with weak lattice energy not only induces the reconstruction of intermolecular interactions to form ion pairs and ion aggregates but also tailors the Zn2+ solvation structure and solid electrolyte interface (SEI). The developed DMEEs possess a dual‐anion‐rich Zn2+ solvation shell and induce an inorganic‐rich hybrid SEI, which effectively suppresses side reactions and obtains a dendrite‐free Zn anode with high reversibility. Remarkably, Zn//Zn cells demonstrate cycling stability for over 3000 h, and Zn//PANI full cells deliver no significant capacity decay after 5000 cycles at a high current density of 5 A g−1. This work opens a new avenue to design advanced deep eutectic electrolytes, and the deep understanding of solvation structure and SEI offers guidelines for developing high‐performance batteries.

Spatial and seasonal groundwater quality assessment for drinking suitability using index and machine learning approach

Spatial and seasonal evaluation and monitoring of groundwater (GW) quality is essential for the sustainable management of this priceless resource and the provision of safe drinking water. Nevertheless, GW quality appraisal was not given due attention in the current study area (flat terrain part of the Tana sub-basin). This study sought to assess the seasonal and regional physicochemical GW quality parameters for drinking appropriateness using the drinking water quality index (DWQI) and support vector machine (SVM). The main cations in both the dry and wet study seasons were, in decreasing order, Na+, Ca2+, Mg2+, K+, and Fe2+, according to the results. Conversely, the main anions were HCO3−, CO32−, Cl− or NO3−, SO42− and PO43−, ordered from higher to lower. During the two research seasons, Ca–HCO3 and Na–HCO3 were the predominant water types based on Piper diagram results. Reverse ion exchange and evaporation were the principal hydrogeochemical processes that control the hydrogeochemistry identified by Durov and Gibbs diagrams, respectively. Excellent GW quality class for drinking was demonstrated by the majority of geographical and seasonal DWQI readings over the two seasons. Nevertheless, during the rainy season, there was a noticeable decline in the GW quality condition around the northern shores of Lake Tana. Therefore, it is advised to implement comprehensive GW quality protection measures and improve system management to mitigate pollution to reduce health hazards in the examined region.

Designing NiFe-metal organic frameworks@NiFe-layered double hydroxide/carbon fiber self-supporting electrode for enhanced capacitive deionization

Self-supporting electrode benefits to enhance the desalination capacity and maximize the capacitance retention by avoiding the usage of organic binders and conductive additives in capacitive deionization (CDI). In this work, we design a self-supporting electrode of NiFe-metal organic framework@NiFe-layered double hydroxides/carbon fiber (MOF@LDH/CC) for highly efficient CDI. The cross-linked CC provides a unique network structure to promote the diffusion of salty ions, leading to high desalination kinetics. On the other hand, the NiFe-MOF acts as seed to induce the growth of NiFe-LDH which not only block the agglomeration of NiFe-LDH layers, but also strengthen the linkage between the CC and NiFe-LDH. As expected, the optimized MOF@LDH/CC//activated carbon CDI system achieves high initial salt removal capacity of 0.033 mg/cm2 in 1000 μS/cm NaCl solution, which decreases to 0.026 mg/cm2 after 30 cycles. The capacity decline is ascribed to the salt deposition during the cycling, which can be observed from the structural evolution. Further, the X-ray photoelectron spectra verifies the reversible chloride ions electro-adsorption/desorption by MOF@LDH/CC. Meanwhile, the porous fibrous structure of MOF@LDH/CC electrode is remaining after few cycles, highlighting the robust structure.

Bimetallic Intercalated Vanadium Oxide As a High-Performance Cathode for Aqueous Zinc Ion Batteries.

In this paper, a bimetallic Na0.13Mg0.02V2O5·0.98H2O (NMVO) material with an interlayer spacing of 11.67 Å was synthesized by a simple preintercalation method as a cathode for zinc ionic batteries (ZIBs). The large layer spacing provides a wide channel for the embedding of Zn2+, resulting in high reversible capacity and ion diffusion kinetics. In addition, by virtue of the high electronic conductivity of metal ions, NMVO exhibits excellent electronic conductivity under the combined action of Na+ and Mg2+ bimetallic intercalation. At the same time, preintercalation ions and structural water act as interlayer pillars to stabilize the layer structure of NMVO during the cycling process. The above reasonable structural design endows the NMVO with excellent electrochemical performance. The battery with NMVO cathode delivers a high initial capacity of 126 mAh g-1 at 10 A g-1, and still remains at 76% after 5000 cycles, providing 100 Wh kg-1 energy density and 9.5 kW kg-1 power density (based on the mass of cathode). This bimetallic intercalation structure provides a general feasible scheme for the design of vanadium-based electrode materials.

Redox-Regulated Synthetic Channels: Enabling Reversible Ion Transport by Modulating the Ion-Permeation Pathway.

Natural redox-regulated channel proteins often utilize disulfide bonds as redox sensors for adaptive regulation of channel conformations in response to diverse physiological environments. In this study, we developed novel synthetic ion channels capable of reversibly switching their ion-transport capabilities by incorporating multiple disulfide bonds into artificial systems. X-ray structural analysis and electrophysiological experiments demonstrated that these disulfide-bridged molecules possess well-defined tubular cavities and can be efficiently inserted into lipid bilayers to form artificial ion channels. More importantly, the disulfide bonds in these molecules serve as redox-tunable switches to regulate the formation and disruption of ion-permeation pathways, thereby achieving a transition in the transmembrane transport process between the ON and OFF states.

Redox‐Regulated Synthetic Channels: Enabling Reversible Ion Transport by Modulating the Ion‐Permeation Pathway

AbstractNatural redox‐regulated channel proteins often utilize disulfide bonds as redox sensors for adaptive regulation of channel conformations in response to diverse physiological environments. In this study, we developed novel synthetic ion channels capable of reversibly switching their ion‐transport capabilities by incorporating multiple disulfide bonds into artificial systems. X‐ray structural analysis and electrophysiological experiments demonstrated that these disulfide‐bridged molecules possess well‐defined tubular cavities and can be efficiently inserted into lipid bilayers to form artificial ion channels. More importantly, the disulfide bonds in these molecules serve as redox‐tunable switches to regulate the formation and disruption of ion‐permeation pathways, thereby achieving a transition in the transmembrane transport process between the ON and OFF states.

Conformational Locking as a Strategy to Reverse Ion Recognition Selectivity.

This study delves into the ion recognition capabilities of a novel host molecule, emphasizing the role of conformational locking in dictating ion selectivity. By employing the Buchwald-Hartwig cross-coupling reaction, we have notably shifted the ion receptor's selectivity from K+ to Na+. The findings are supported by computational simulations that reveal differences in binding energies and molecular strain impacting ion recognition. This innovative structural modification broadens the scope for alterations at the calix[4]arene's lower rim, paving the way for new methods and strategies in modulating ion recognition selectivity.

Purines recognition and quantitative analysis by surface-enhanced Raman spectroscopy

The common quantification methods of purines, including high-performance liquid chromatography, micellar electrokinetic chromatography, reverse phase ion pair chromatography, and capillary zone electrophoresis, have been used for the analysis of purines. These conventional techniques are limited by long operation times, large sample volumes, requirements for pretreatment and separation processes, or sophisticated, bulky and expensive equipment. Here, we have developed a simple method to prepare a probe for the quantitative analysis of purines using the surface-enhanced Raman scattering (SERS) method. The SERS probe is a rough Ag wire obtained with simple electrochemical treatment, which is optimized to reach the maximum SERS signal enhancement. The Raman enhancement factor (EF) of Ag wire after roughening can reach ∼106. Under optimized conditions, the rough Ag wire is capable of recognizing four purine bases (namely, guanine, adenine, hypoxanthine, and xanthine) in the range of 10−5 to 10−1 mg/mL with a linear relationship between SERS intensity of signature peak and purine concentration. The recovery rate of each purine base is higher than 80% in the mixture of four purines. The overall method was successfully applied to the monitoring of the level of purines in marketplace beer beverages. The novel wire-based SERS sensor used with portable Raman spectroscopy is prospective in diet safety and personalized point-of-care medical detection.

Interfacial Engineering of Zn Metal via a Localized Conjugated Layer for Highly Reversible Aqueous Zinc Ion Battery.

Aqueous zinc-ion batteries are regarded as promising and efficient energy storage systems owing to remarkable safety and satisfactory capacity. Nevertheless, the instability of zinc metal anodes, characterized by issues such as dendrite growth and parasitic side reactions, poses a significant barrier to widespread applications. Herein, we address this challenge by designing a localized conjugated structure comprising a cyclic polyacrylonitrile polymer (CPANZ), induced by a Zn2+-based Lewis acid (zinc trifluoromethylsulfonate) at a temperature of 120 °C. The CPANZ layer on the Zn anode, enriched with appropriate pyridine nitrogen-rich groups (conjugated cyclic -C=N-), exhibits a notable affinity for Zn2+ with ample deposition sites. This zincophilic skeleton not only serves as a protective layer to guide the deposition of Zn2+ but also functions as proton channel blocker, regulating the proton flux to mitigate the hydrogen evolution. Additionally, the strong adhesion strength of the CPANZ layer guarantees its sustained protection to the Zn metal during long-term cycling. As a result, the modified zinc electrode demonstrates long cycle life and high durability in both half-cell and pouch cells. These findings present a feasible approach to designing high performance aqueous anodes by introducing a localized conjugated layer.

Interfacial Engineering of Zn Metal via a Localized Conjugated Layer for Highly Reversible Aqueous Zinc Ion Battery

AbstractAqueous zinc‐ion batteries are regarded as promising and efficient energy storage systems owing to remarkable safety and satisfactory capacity. Nevertheless, the instability of zinc metal anodes, characterized by issues such as dendrite growth and parasitic side reactions, poses a significant barrier to widespread applications. Herein, we address this challenge by designing a localized conjugated structure comprising a cyclic polyacrylonitrile polymer (CPANZ), induced by a Zn2+‐based Lewis acid (zinc trifluoromethylsulfonate) at a temperature of 120 °C. The CPANZ layer on the Zn anode, enriched with appropriate pyridine nitrogen‐rich groups (conjugated cyclic −C=N−), exhibits a notable affinity for Zn2+ with ample deposition sites. This zincophilic skeleton not only serves as a protective layer to guide the deposition of Zn2+ but also functions as proton channel blocker, regulating the proton flux to mitigate the hydrogen evolution. Additionally, the strong adhesion strength of the CPANZ layer guarantees its sustained protection to the Zn metal during long‐term cycling. As a result, the modified zinc electrode demonstrates long cycle life and high durability in both half‐cell and pouch cells. These findings present a feasible approach to designing high performance aqueous anodes by introducing a localized conjugated layer.

α-α Coupling-Dominated PPy Film with a Well-Conjugated Structure for Superlong Cycle Life Supercapacitors.

As the electrode of a supercapacitor, polypyrrole (PPy) inevitably suffers from structural rupture during repeated doping/dedoping processes and releases low practical capacitance due to the large amount of aggregation or cross-linking in PPy chains. The coupling mode (α-α, α-β, or β-β coupling) of pyrroles is critical to the conjugated structure, the conductivity, and cycling stability of PPy. Here, we prepared an α-α coupling-dominated PPy film via simple frozen interfacial polymerization. The PPy film with a nanostructure exposes more electrochemical active sites for the electrode, which can enhance the practical capacitance. The high proportion of the α-α coupling mode results in a high degree of large π-conjugation and a planar structure that can effectively improve the reversible ion transport efficiency and promote uniform stress distribution during the charge and discharge process. The assembled symmetric water-based supercapacitor delivers a high specific capacitance of 267.1 F g-1 at 1 A g-1 and 266.7 F g-1 at 5 A g-1 and exhibits an outstanding cycling performance of above 200 F g-1 even after 60,000 cycles.

Simulation of Rock-Water Interaction in the Southwestern Part of El Minya Governorate of Egypt

Abstract Twenty-one groundwater samples were picked up from the southwest of El Minya Governorate, Egypt. These samples’ physicochemical characteristics were analyzed. Using a water quality index software (WQI) and the United States Salinity Laboratory (USSL) staff chart, water samples were assessed for drinking and irrigation applications. The interaction between water and rock was assessed using the saturation index (SI), chloro-alkaline indices (CAI), Gibbs ratios (GC and GA), end-member diagram (END), corrosion ratio (CR), factor analysis, and dendrogram. Datasets elucidated that water samples were distinguished by SO42-, Na+, and Cl- dominance, excessive mineralization, hardness, and fresh to slightly saline water. The examined water is divided into two types: SO4. Ca-Cl. Mg (30%) and SO4. Na-Cl (70%). All samples were over-saturated with anhydrite, aragonite, calcite, dolomite, and gypsum minerals except for halite and sylvite minerals dissolution, according to SI. The existence of reversible ion exchange between alkaline earth’s (Ca2++Mg2+) ions in water and alkalis’ ions (Na++ K+) in solids; this is explained by the negative values of the chloro-alkaline indices, which point to recharging from rainfall. The Gibbs diagram showed that the dominant interaction is rock weathering. The silicate weathering and evaporite mineral dissolution control the water composition and salinity, which led to an excess of the dominant ions, as demonstrated by the END. Three wells in the research area are potentially unhealthy and unfit for irrigation and drinking.

Hydrochemical assessment of groundwater using multivariate statistical methods and water quality indices (WQIs)

Groundwater quality assessment is crucial for the sustainable management of water resources in arid regions, where groundwater is the primary source of water supply and increasing demand raises concerns. The study area in Southwest Algeria relies heavily on groundwater as a source of water supply, and the increasing demand for freshwater raises concerns about the quality of groundwater. To assess the hydrochemical characteristics and water quality of groundwater in the Ain Sefra region, multivariate statistical methods, geochemical modeling and water quality indices were employed. The study revealed that the groundwater samples could be classified into four water groups using hierarchical cluster analysis Q mode (HCA), namely Ca–Mg–HCO3, Ca–Mg–Cl–SO4, Ca–SO4 and Na–Cl. Factor analysis was used to identify the main factors controlling the study area’s hydrochemical processes. The results indicated that water–rock interaction, reverse ion exchange and anthropogenic pollution were the main hydrochemical processes affecting groundwater chemistry. The water quality index indicated that the groundwater was suitable for human consumption, with only 2.32% of the samples being unsuitable. Additionally, the groundwater was suitable for agricultural use, but salinity control was necessary. The saturation index values showed that the groundwater was supersaturated with aragonite, calcite, dolomite, anhydrite and gypsum, and undersaturated with halite. Ca-smectite, Mg-smectite and kaolinite were identified as the primary processes controlling the chemical composition of groundwater. The application of multivariate statistical methods, geochemical modeling and water quality indices provided a comprehensive understanding of the hydrochemical characteristics and water quality of groundwater in the Ain Sefra region. The findings of the study can serve as a useful basis for future studies on groundwater quality assessment in the region.

Evaluation of spatial and temporal dynamics of seawater intrusion in coastal aquifers of southeast India: insights from hydrochemical facies analysis.

This study aims to investigate and understand the temporal and spatial movement of seawater intrusion into the coastal aquifers. Groundwater salinity increase has affected the entire eastern part of the study area and is primarily influenced by direct and reverse ion exchange reactions associated with intrusion and freshwater influx phases, which alternate over monsoons. To gain insights into the spatiotemporal dynamics of the seawater intrusion process, hydrochemical facies analysis utilizing the HFE-Diagram was employed. Additionally, the study considered the major ionic changes during both the monsoons. The HFE-Diagram analysis of hydrochemical facies revealed distinctions in the behaviour of each coastal aquifer concerning seawater intrusion-induced salinization. In PRM 2020, the data shows that approximately 65% of the samples fall under the freshening phase, while the remaining 35% were categorized as intrusion phase. Within the freshening phase, seven different hydrochemical facies were identified, including Na-Cl, Na-MixCl, MixNa-MixCl, Na-MixHCO3/MixSO4, MixNa-MixSO4, Na-HCO3, and MixCa-HCO3. In contrast, the intrusion phase had four facies: MixCaMixHCO3, MixNa-Cl, Ca-Cl, and Na-Cl. Especially, the Na-Cl facies (f1) within the freshening phase attributed for the largest percentage, contributing 30% of the samples. In POM 2021, the distribution of samples shifted slightly, with approximately 72.5% belonging to the freshening phase and 27.5% to the intrusion phase. Within the freshening phase of POM 2021, five hydrochemical facies were identified: Na-Cl, Na-MixCl, Na-MixHCO3/MixSO4, MixNa-MixSO4, and Na-HCO3. The intrusion phase of POM 2021 had three facies: MixNa-Cl, Na-Cl, and MixCa-Cl. Similar to PRM 2020, the Na-Cl facies (f1) remained the most predominant in the freshening phase, comprising 30% of the samples. The relation between total dissolved solids (TDS) and various ionic ratios, such as HCO3-/Cl-, Na+/Cl-, Ca2+/Cl-, Mg2+/Cl-, K+/Cl-, and SO42-/Cl-, clearly demonstrates the presence of seawater influence within the coastal aquifers of the study area.

Construction of fully coated polypyrrole oxygen-barrier film based on MXene nanosheets for high reliability capacitive deionization

MXene has emerged as a promising capacitive deionization (CDI) faradic material for the advantages of excellent hydrophilicity, outstanding specific capacitance, and highly reversible ions intercalation/de-intercalation. However, its practical applications are severely restricted by the bottleneck problems of severe self-stacking and susceptibility to be oxidized by dissolved oxygen in aqueous solution. Herein, polypyrrole (PPy) oxygen-barrier film was fabricated and fully coated on the surface of MXene by the in-situ polymerization method to construct the composite electrode of PPy@MXene. In this unique architecture, the PPy oxygen-barrier film both enhances the antioxidant properties of MXene and weakens the strong interfacial interactions between MXene nanosheets to reduce the self-aggregation. Meanwhile, by doping different ions (Cl– and dodecyl benzene sulfonate, DBS–), PPy films were provided with excellent conductivity, abundant hole sites, and good ion exchange properties, which significantly promoted the charge priority adsorption capability of PPy-Cl@MXene and PPy-DBS@MXene electrodes. Consequently, compared with MXene//MXene cell, the PPy-Cl@MXene//PPy-DBS@MXene CDI cell presents dominant deionization capacity (55 mg g−1) and outstanding cycling stability (3 % degradation after 40 cycles). Most importantly, the morphology, structure and surface charge characteristics of the electrodes after long-term desalination confirmed that the MXene with fully coated PPy film was not destroyed by dissolved oxygen and maintained good structural integrity, which is conducive to improving the reliability of the MXene-based electrodes in CDI. Additionally, ion doped PPy@MXene electrodes highlight preferential adsorption to divalent cations. The work proposes a new strategy to advance the practical application of MXene by simultaneously solving its self-stacking and oxidative degradation issues.

Hierarchically Structured Nb2O5 Microflowers with Enhanced Capacity and Fast-Charging Capability for Flexible Planar Sodium Ion Micro-Supercapacitors

HighlightsHierarchically structured Nb2O5 microflowers consiste of porous and ultrathin nanosheets.Nb2O5 microflowers exhibit enhanced capacity and rate performance boosting Na ion storage.Planar NIMSCs with charge and kinetics matching show superior areal capacitance and lifespan.Planar Na ion micro-supercapacitors (NIMSCs) that offer both high energy density and power density are deemed to a promising class of miniaturized power sources for wearable and portable microelectronics. Nevertheless, the development of NIMSCs are hugely impeded by the low capacity and sluggish Na ion kinetics in the negative electrode. Herein, we demonstrate a novel carbon-coated Nb2O5 microflower with a hierarchical structure composed of vertically intercrossed and porous nanosheets, boosting Na ion storage performance. The unique structural merits, including uniform carbon coating, ultrathin nanosheets and abundant pores, endow the Nb2O5 microflower with highly reversible Na ion storage capacity of 245 mAh g−1 at 0.25 C and excellent rate capability. Benefiting from high capacity and fast charging of Nb2O5 microflower, the planar NIMSCs consisted of Nb2O5 negative electrode and activated carbon positive electrode deliver high areal energy density of 60.7 μWh cm−2, considerable voltage window of 3.5 V and extraordinary cyclability. Therefore, this work exploits a structural design strategy towards electrode materials for application in NIMSCs, holding great promise for flexible microelectronics.

Correction: Mimicking ion and water management in poultry breeding for highly reversible zinc ion batteries

Correction for ‘Mimicking ion and water management in poultry breeding for highly reversible zinc ion batteries’ by Shengli Zhai et al., Energy Environ. Sci., 2023, 16, 5479–5489, https://doi.org/10.1039/D3EE03045H.