Changes In Cell Volume Research Articles

Weekly dynamics of abundance and size structure of specific nanophytoplankton lineages in coastal waters (Baltic Sea)

AbstractNanophytoplankton, the key component of algal communities, remains understudied, thus there is a substantial knowledge gap about dynamics of abundance, biovolume, and cell size of specific algae. Here, I studied weekly changes in abundance, biovolume, cell volume, and cell surface to volume (SV) ratio (> 11,700 cells measured) of specific nanophytoplankton groups using amplicon sequencing and catalyzed reported deposition‐fluorescence in situ hybridization. I applied oligonucleotide probes to study major nanophytoplankton groups: chlorophytes, chrysophytes, pelagophytes, cryptophytes, pedinellids, and haptophytes. I designed three novel probes, two for pedinellid species Apedinella radians and Pseudopedinella elastica, and for a haptophyte genus Haptolina. Chlorophytes were the most abundant group, followed by haptophytes and cryptophytes. Abundance and biovolume of specific groups showed distinct seasonal dynamics and fluctuated up to 100‐fold within a week. Different groups contributed to nanophytoplankton peaks over the season, and this pattern was consistent down to a genus/species level, as shown for cryptophytes, pedinellids, and haptophytes. Inorganic nutrients were the best explanatory variables for abundance and biovolume, but their importance varied for specific groups. Thus, the differences in seasonal dynamics of different algal groups can be explained by temporal niche separation between them. Changes in nanophytoplankton size structure were substantial, and cell volume varied over 104‐fold. However, the size dynamics (variability in cell volume and SV ratio) was lower at genus/species level, indicating changes in nanophytoplankton size structure likely resulted from changes in community composition. Temperature and nutrients best explained the size dynamics, but their explanatory power differed for specific nanophytoplankton groups.

Hydrogen storage performances of RCaMgNi9 (R = Nd, Gd and Er) compounds

The influence of substitution of R (R = Nd, Gd and Er) for Ca on hydrogen storage performances of Ca2MgNi9 compound was investigated. RCaMgNi9 compounds have obvious hydrogen absorption and desorption plateaus though their hydrogen storage capacities are reduced with the decrease of atomic radii of R. The hydriding enthalpies of RCaMgNi9 (R = Nd, Gd and Er) range from −30.4 to −19.5 kJ mol−1 H2 as the change of cell volumes. Moreover, RCaMgNi9 alloy electrodes show better cycle stabilities and high-rate discharge capacities than Ca2MgNi9. However, GdCaMgNi9 and ErCaMgNi9 have relatively worse hydrogen storage properties as compared to NdCaMgNi9 due to the small atomic radii of Gd and Er.

Methamphetamine-induced apoptosis in glial cells examined under marker-free imaging modalities.

.We used phase microscopy and Raman spectroscopic measurements to assess the response of in vitro rat C6 glial cells following methamphetamine treatment in real time. Digital holographic microscopy (DHM) and three-dimensional (3-D) tomographic nanoscopy allow measurements of live cell cultures, which yield information about cell volume changes. Tomographic phase imaging provides 3-D information about the refractive index distribution associated with the morphology of biological samples. DHM provides similar information, but for a larger population of cells. Morphological changes in cells are associated with alterations in cell cycle and initiation of cell death mechanisms. Raman spectroscopy measurements provide information about chemical changes within the cells. Our Raman data indicate that the chemical changes in proteins preceded morphological changes, which were seen with DHM. Our study also emphasizes that tomographic phase imaging, DHM, and Raman spectroscopy are imaging tools that can be utilized for noninvasive simultaneous monitoring of morphological and chemical changes in cells during apoptosis and can also be used to monitor other dynamic cell processes.

Giant barocaloric effect in all- d -metal Heusler shape memory alloys

The large change of unit cell volume at the martensitic transition of all-$d$-metal Heusler shape memory alloys suggests that these compounds are prone to exhibit a large barocaloric response. In this paper, the composition of a Ni-Mn-Ti alloy has been tailored so that it undergoes a martenistic transition between two structural phases which do not ferromagnetically order, thereby leading to a large transition entropy change. The combination of large entropy and volume changes confers to this alloy an outstanding barocaloric effect close to room temperature. The barocaloric performances found for the studied compound outperform those reported for other shape memory Heusler alloys, and are among the largest values reported for the best state-of-the-art intermetallic compounds. The reported results place all-$d$-metal Heusler shape memory alloys at the forefront of caloric materials to be used in clean solid-state refrigeration technologies.

Regulation of K‐Cl cotransporters (KCCs) activity by a PP1 phosphatase/WNK3 kinase complex

Study ObjectiveTo identify and characterize the mechanism protein phosphatases use to regulate KCCs activity during ionic homeostasis and the regulation of cell volume via WNK3 kinase.BackgroundSLC12A family are membrane proteins that transport Na+ and/or K+ coupled to Clinside and outside the cell. They regulate cell volume, trans‐epithelial ionic transport, neuron excitability and blood pressure balance. Several members of the family and their regulatory proteins are mutated in human diseases characterized by alteration of ionic homeostasis mainly in the kidney and the brain. The family is formed by KCCs, NCC and NKCCs regulated in a reciprocal manner by phospho‐ and dephosphorylation events. WNKs kinases and their down‐stream substrates, SPAK/OSR1 are their main phospho‐regulatory proteins. Dephosphorylation results in KCCs activation and NCC and NKCCs inhibition, whereas phosphorylation produces the opposite effect. KCCs activation is abolished by inhibition of PP1A and PP2, demonstrating an essential regulatory role for PPs in this process. Substrate specificity for WNK and SPAK/OSR1 kinases is stablished by a SPAK binding motif, present in WNK kinases and the SLC12A. Conversely, some consensus motifs for direct PPs‐dephosphorylation have been stablished. In the present study we analyzed two putative PP1 binding sites present in the WNK3 kinase sequence. Our previous findings showed that WNK3 inhibits all the KCCs and its catalytically inactive form, WNK3 DA activates them. Inhibition of PPs showed regulation of KCCs activity by WNK3 depends on PPs activity. By mutating these putative PP1 binding sites we are aiming to identify the serine (Ser)‐threonine (Thr) kinases/phosphatases complex involved in KCCs response to cell volume changes regulated by WNK3.MethodsKCCs dephosphorylation was evaluated by Western Blot analysis. from HEK 293 cells transfected with either WT WNK3 kinase (WNK3 WT), catalytically inactive WNK3 (WNK3 DA), or PP1 binding sites mutant WNK3 (WNK3 PP1A, WNK3 DA PP1A, WNK3 PP1B or WNK3 DA PP1B) Cells were stimulated with either isotonic or hypotonic buffers in order to stimulate phosphatase activity under KCCs regulatory phosphorylation sites (pT1039 and pT991 in KCC3a). Regulation of KCCs K‐Cl transport by WNK3 WT, DA and mutants was assayed directly in Xenopus laevis oocytes. Formation of a kinase/phosphatase/cotransporter complex was evaluated by immunoprecipitation assays.ResultsData obtained in HEK cells and X. laevis oocytes showed that WNK3 PP1 binding sites mutation modified the effect of WNK3 WT and WNK3 DA previously reported over KCCs in response to cell volume changes.ConclusionsBinding of PP1 to WNK3 and formation of a regulatory complex is necessary for WNK3 to regulate SLC12A family response to osmotic and cell volume changes.Support or Funding InformationPAPIIT IA207718CONACYT, CB‐2016‐01, 283555This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Quantitative Evaluation of Long-Range and Cooperative Ion Effect on Water in Polyamide Network.

Despite long-standing research efforts to elucidate the specific ion effect on the structure and dynamics of water, the spatial extent affected by ions and the cooperativity of ions and counterions are still controversial. Here, we demonstrate an undoubtable evidence of long-range and cooperative ion effect on water molecules in a polyamide network by using a precision ion sensor of photonic crystal hydrogel membrane. The ion effect was quantitatively evaluated by means of the osmotic work per unit cell volume change of photonic crystal, Wunit, required for the ion-inhibited dehydration, which means a suppressed migration of water molecules by the extensive effect of ions beyond their immediate hydration shells. It was found that Wunit required for 14 vol % contraction of the membrane sensor in LiCl aqueous solutions was7.7 times larger than that in Sr(NO3)2 solutions. The combination of structure-making Ca2+ and Sr2+ with nitrate anions lowered the ion effect than the chloride salts of borderline Na+ and Ba2+. Furthermore, the nitrate salt of Sr2+ exhibited a lower ion effect than the chloride salts of structure-breaking K+ and Cs+.These results have revealed that the ion effect acts to water extensively, which is modulated by cooperative interactions of ions and counterions.

Enhanced oxygen mobility by doping Yb in BaGd1-xYbxMn2O5+δ double perovskite-structured oxygen storage materials

The A-site ordered BaGd1-xYbxMn2O5+δ double perovskites have been systematically investigated in terms of the crystal structure, oxygen nonstoichiometry, microstructure and oxidation states of Mn, oxygen storage properties and oxygen in-situ intake, as well as transport properties. The increased content of Yb in BaGd1-xYbxMn2O5+δ results in a decrease of the relative unit cell volume changes between oxidized materials and reduced counterparts. Crystal structure with P4/nmm space group is observed at room temperature in all BaGd1-xYbxMn2O5+δ (x = 0, 0.2 and 0.4), except in BaGd0.6Yb0.4Mn2O6. The increased content of Yb in BaGd1-xYbxMn2O5+δ modifies materials' morphology, allowing to obtain fine powders. The Mn2+ and/or Mn3+ oxidation states are present in the reduced BaGd1-xYbxMn2O5, confirmed by XPS studies. The Yb doping in BaGd0.6Yb0.4Mn2O5+δ significantly decreases the reduction time and oxidation/reduction temperature. The in-situ oxidation of BaGd0.6Yb0.4Mn2O5 in air associated with P4/nmm → P-1 space group change occurs between 225 and 275 °C, and its nature may indicate the oxygen diffusion mainly occurs in the Gd0.6Yb0.4 layers. The TEC values calculated from high temperature XRD data, not exceeding 14.8(1) × 10−6 K−1, are moderate. The high electrical conductivity (100 S cm−1 in air at 600 °C) and high oxygen diffusion coefficient suggest wide potential applications of the developed BaGd0.6Yb0.4Mn2O5+δ.

Probing into the working mechanism of Mg versus Co in enhancing the electrochemical performance of P2-Type layered composite for sodium-ion batteries

As a cost-effective element, Mg has been applied as doped inactive atom to improve the electrochemical performance of sodium-ion cathode materials. Herein, we report Mg-substituted Na0.67Mn0.65Ni0.2Co0.15-xMgxO2 composites as high-performance cathode for sodium-ion batteries and investigate the underlying working mechanism using in situ investigation techniques to monitor the operando changes of electrodes. In situ X-ray diffraction investigation demonstrates P2-type structure is well preserved even charged to 4.3 V and the changes of lattice parameters and unit cell volume of Na0.67Mn0.65Ni0.2Mg0.15O2 are alleviated via Mg replacement. As a result, the capacity retention increases from 62% in Na0.67Mn0.65Ni0.2Co0.15O2 to 94% in Na0.67Mn0.65Ni0.2Mg0.15O2. Meanwhile, less CO2 evolution was detected in the coin cell with Na0.67Mn0.65Ni0.2Mg0.15O2 electrode than in that with Na0.67Mn0.65Ni0.2Co0.15O2 electrode in online differential electrochemical mass spectrometry test, suggesting a depressed side reaction between electrode and electrolyte after Mg completely replacing Co. In situ electrochemical impedance spectroscopy investigation further proves Mg is beneficial for the interfacial conductivity enhancement compared to Co, which provides evidence for enhanced high rate capabilities. These comprehensive results provide new viewpoints to explain the improved cycling and rate capabilities from the aspects of crystal structure evolution, coin cell gas evolution and electrolyte/electrode interface conductivity during charge/discharge process.

Plant nyctinasty - who will decode the 'Rosetta Stone'?

Nyctinasty is the circadian rhythmic nastic movement of leguminous plants in response to the onset of darkness, a unique and intriguing phenomenon that has attracted attention for centuries. The movement itself is caused by the asymmetric volume change of motor cells between the adaxial and abaxial sides of the leaflet. Recently, we identified the ion channels responsible for the volume change of motor cells during the leaf-opening process of Samanea saman; the asymmetric expression of SsSLAH1, which is under the control of SsCCA1, was found to play a key role in this process. Here, we summarize the history of the study of nyctinasty, our current results and several insights for further study.

The Volume-Regulated Anion Channel in Glioblastoma.

Malignancy of glioblastoma multiforme (GBM), the most common and aggressive form of human brain tumor, strongly depends on its enhanced cell invasion and death evasion which make surgery and accompanying therapies highly ineffective. Several ion channels that regulate membrane potential, cytosolic Ca2+ concentration and cell volume in GBM cells play significant roles in sustaining these processes. Among them, the volume-regulated anion channel (VRAC), which mediates the swelling-activated chloride current (IClswell) and is highly expressed in GBM cells, arguably plays a major role. VRAC is primarily involved in reestablishing the original cell volume that may be lost under several physiopathological conditions, but also in sustaining the shape and cell volume changes needed for cell migration and proliferation. While experimentally VRAC is activated by exposing cells to hypotonic solutions that cause the increase of cell volume, in vivo it is thought to be controlled by several different stimuli and modulators. In this review we focus on our recent work showing that two conditions normally occurring in pathological GBM tissues, namely high serum levels and severe hypoxia, were both able to activate VRAC, and their activation was found to promote cell migration and resistance to cell death, both features enhancing GBM malignancy. Also, the fact that the signal transduction pathway leading to VRAC activation appears to involve GBM specific intracellular components, such as diacylglicerol kinase and phosphatidic acid, reportedly not involved in the activation of VRAC in healthy tissues, is a relevant finding. Based on these observations and the impact of VRAC in the physiopathology of GBM, targeting this channel or its intracellular regulators may represent an effective strategy to contrast this lethal tumor.

Phase transformation behavior of ultrathin Hf0.5Zr0.5O2 films investigated through wide range annealing experiments

Hf0.5Zr0.5O2 thin films are not always ferroelectric. This work investigates the impact of annealing temperature and time on the crystalline structures and dielectric properties of 10 nm thick Hf0.5Zr0.5O2 thin films. It is found that the tetragonal phase crystal is formed from the amorphous film firstly, then transforms to the orthorhombic and monoclinic phases, in accordance with the annealing temperature and time. The volume fraction of the orthorhombic phase in the film, which is known as the origin of ferroelectricity, becomes dominant in a certain range of the annealing condition. Thus, the annealing temperature and time are responsible for the anti-ferroelectric, ferroelectric, and paraelectric characteristics of Hf0.5Zr0.5O2 thin films. This phase transformation behavior is discussed from the viewpoint of formation energies of the respective crystal phases, which accompanies the changes of unit cell volumes. The competition of transformation rates between the tetragonal to orthorhombic and the orthorhombic to monoclinic is key for the formation of ferroelectric films.

Fluid dynamics during bleb formation in migrating cells in vivo.

Blebs are cellular protrusions observed in migrating cells and in cells undergoing spreading, cytokinesis, and apoptosis. Here we investigate the flow of cytoplasm during bleb formation and the concurrent changes in cell volume using zebrafish primordial germ cells (PGCs) as an in vivo model. We show that bleb inflation occurs concomitantly with cytoplasmic inflow into it and that during this process the total cell volume does not change. We thus show that bleb formation in primordial germ cells results primarily from redistribution of material within the cell rather than being driven by flow of water from an external source.

Anomalous Temperature Dependence of the Lowest-Frequency Lattice Vibration in Crystalline γ-Aminobutyric Acid.

Crystalline γ-aminobutyric acid (GABA) exhibits unusual thermal behavior in a low-frequency lattice vibration that occurs at 37.2 cm-1 at 290 K but decreases dramatically by 34.0% when the sample is cooled to 78 K. Lattice vibrations in molecular crystals are indicators of intermolecular force characteristics, and the extraordinary temperature sensitivity of this vibration offers new insight into the local environment within the solid. Solid-state density functional theory simulations of the GABA crystal have found this anomalous frequency shift is based in unexpected differences in the strengths of the intermolecular hydrogen bonds that are cursorily the same. This was accomplished through mapping of the potential energy surfaces governing the terahertz-frequency motions of the GABA solid and use of the quasi-harmonic approximation to model the response of all the lattice vibrations to temperature-induced unit cell volume changes brought about through the anharmonic character of the intermolecular interactions. The analysis reveals that the vibration in question is rotational in nature and involves the significant distortion of a specific weak intermolecular N-H···O hydrogen bond in the crystal that results in its unique thermal response.

Regulation of extracellular ATP of human erythrocytes treated with α-hemolysin. Effects of cell volume, morphology, rheology and hemolysis

Alpha-hemolysin (HlyA) of uropathogenic strains of Escherichia coli irreversibly binds to human erythrocytes (RBCs) and triggers activation of ATP release and metabolic changes ultimately leading to hemolysis.We studied the regulation of extracellular ATP (ATPe) of RBCs exposed to HlyA. Luminometry was used to assess ATP release and ATPe hydrolysis, whereas changes in cell volume and morphology were determined by electrical impedance, ektacytometry and aggregometry.Exposure of RBCs to HlyA induced a strong increase of [ATPe] (3–36-fold) and hemolysis (1–44-fold), partially compensated by [ATPe] hydrolysis by ectoATPases and intracellular ATPases released by dead cells. Carbenoxolone, a pannexin 1 inhibitor, partially inhibited ATP release (43–67%).The un-acylated toxin ProHlyA and the deletion analog HlyA∆914-936 were unable to induce ATP release or hemolysis.For HlyA treated RBCs, a data driven mathematical model showed that simultaneous lytic and non-lytic release mainly governed ATPe kinetics, while ATPe hydrolysis became important after prolonged toxin exposure.HlyA induced a 1.5-fold swelling, while blocking this swelling reduced ATP release by 77%. Blocking ATPe activation of purinergic P2X receptors reduced swelling by 60–80%. HlyA-RBCs showed an acute 1.3–2.2-fold increase of Ca2+i, increased crenation and externalization of phosphatidylserine. Perfusion of HlyA-RBCs through adhesion platforms showed strong adhesion to activated HMEC cells, followed by rapid detachment. HlyA exposed RBCs exhibited increased sphericity under osmotic stress, reduced elongation under shear stress, and very low aggregation in viscous media.Overall results showed that HlyA-RBCs displayed activated ATP release, high but weak adhesivity, low deformability and aggregability and high sphericity.

Effect of acute hypohydration on glycemic regulation in healthy adults: a randomized crossover trial.

The aim of this study was to investigate the acute effect of hydration status on glycemic regulation in healthy adults and explore underlying mechanisms. In this randomized crossover trial, 16 healthy adults (8 men, 8 women) underwent an oral glucose tolerance test (OGTT) when hypohydrated and rehydrated after 4 days of pretrial standardization. One day before OGTT, participants were dehydrated for 1 h in a heat tent with subsequent fluid restriction (HYPO) or replacement (RE). The following day, an OGTT was performed with metabolic rate measurements and pre- and post-OGTT muscle biopsies. Peripheral quantitative computer tomography thigh scans were taken before and after intervention to infer changes in cell volume. HYPO (but not RE) induced 1.9% (SD 1.2) body mass loss, 2.9% (SD 2.7) cell volume reduction, and increased urinary hydration markers, serum osmolality, and plasma copeptin concentration (all P ≤ 0.007). Fasted serum glucose [HYPO 5.10 mmol/l (SD 0.42), RE 5.02 mmol/l (SD 0.40); P = 0.327] and insulin [HYPO 27.1 pmol/l (SD 9.7), RE 27.6 pmol/l (SD 9.2); P = 0.809] concentrations were similar between HYPO and RE. Hydration status did not alter the serum glucose ( P = 0.627) or insulin ( P = 0.200) responses during the OGTT. Muscle water content was lower before OGTT after HYPO compared with RE [761 g/kg wet wt (SD 13) vs. 772 g/kg wet wt (SD 18) RE] but similar after OGTT [HYPO 779 g/kg wet wt (SD 15) vs. RE 780 g/kg wet wt (SD 20); time P = 0.011; trial × time P = 0.055]. Resting energy expenditure was similar between hydration states (stable between -1.21 and 5.94 kJ·kg-1·day-1; trial P = 0.904). Overall, despite acute mild hypohydration increasing plasma copeptin concentrations and decreasing fasted cell volume and muscle water, we found no effect on glycemic regulation. NEW & NOTEWORTHY We demonstrated for the first time that an acute bout of hypohydration does not impact blood sugar control in healthy adults. Physiological responses to mild hypohydration (<2% body mass loss) caused an elevation in copeptin concentrations similar to that seen in those with diabetes as well as reducing cell volume by ~3%; both of these changes had been hypothesized to cause a higher blood sugar response.

Metamagnetism in manganate magnesium ferrite

Abstract The metamagnetic properties of the manganese magnesium ferrites having the general formula Mn0.7Mg0.3Fe2O4 prepared by the standard ceramic technique have been studied. It is proposed that when a change of temperature at adequate magnetic field is applied in a Mn0.7Mg0.3Fe2O4 a magnetic phase transition will be generated, giving rise to an antiferromagnetic (AFM) state from ferrimagnetic (FM) phase. The critical transition field H ac = 300 A/m was estimated for critical magnetization curve of transition from the metamagnetic behavior to FM behavior of sample. The FM to AFM transition in these ferrites is accompanied by a Néel type to Yafet-Kittel type transition and gradual spin ordering changes of the unit cell volume. The application of an external magnetic field to the low-temperatures AFM state causes the sample to reset to the original FM state.

A 30-year journey from volume-regulated anion currents to molecular structure of the LRRC8 channel.

The swelling-activated anion channel VRAC has fascinated and frustrated physiologists since it was first described in 1988. Multiple laboratories have defined VRAC's biophysical properties and have shown that it plays a central role in cell volume regulation and possibly other fundamental physiological processes. However, confusion and intense controversy surrounding the channel's molecular identity greatly hindered progress in the field for >15 yr. A major breakthrough came in 2014 with the demonstration that VRAC is a heteromeric channel encoded by five members of the Lrrc8 gene family, Lrrc8A-E. A mere 4 yr later, four laboratories described cryo-EM structures of LRRC8A homomeric channels. As the melee of structure/function and physiology studies begins, it is critical that this work be framed by a clear understanding of VRAC biophysics, regulation, and cellular physiology as well as by the field's past confusion and controversies. That understanding is essential for the design and interpretation of structure/function studies, studies of VRAC physiology, and studies aimed at addressing the vexing problem of how the channel detects cell volume changes. In this review we discuss key aspects of VRAC biophysics, regulation, and function and integrate these into our emerging understanding of LRRC8 protein structure/function.

Impact of the Environment upon the Candida albicans Cell Wall and Resultant Effects upon Immune Surveillance.

The fungal cell wall is an essential organelle that maintains cellular morphology and protects the fungus from environmental insults. For fungal pathogens such as Candida albicans, it provides a degree of protection against attack by host immune defences. However, the cell wall also presents key epitopes that trigger host immunity and attractive targets for antifungal drugs. Rather than being a rigid shield, it has become clear that the fungal cell wall is an elastic organelle that permits rapid changes in cell volume and the transit of large liposomal particles such as extracellular vesicles. The fungal cell wall is also flexible in that it adapts to local environmental inputs, thereby enhancing the fitness of the fungus in these microenvironments. Recent evidence indicates that this cell wall adaptation affects host-fungus interactions by altering the exposure of major cell wall epitopes that are recognised by innate immune cells. Therefore, we discuss the impact of environmental adaptation upon fungal cell wall structure, and how this affects immune recognition, focussing on C. albicans and drawing parallels with other fungal pathogens.

Analysis of novel hyperosmotic shock response suggests 'beads in liquid' cytosol structure.

ABSTRACTProteins can aggregate in response to stresses, including hyperosmotic shock. Formation and disassembly of aggregates is a relatively slow process. We describe a novel instant response of the cell to hyperosmosis, during which chaperones and other proteins form numerous foci with properties uncharacteristic of classical aggregates. These foci appeared/disappeared seconds after shock onset/removal, in close correlation with cell volume changes. Genome-wide and targeted testing revealed chaperones, metabolic enzymes, P-body components and amyloidogenic proteins in the foci. Most of these proteins can form large assemblies and for some, the assembled state was pre-requisite for participation in foci. A genome-wide screen failed to identify genes whose absence prevented foci participation by Hsp70. Shapes of and interconnections between foci, revealed by super-resolution microscopy, indicated that the foci were compressed between other entities. Based on our findings, we suggest a new model of cytosol architecture as a collection of numerous gel-like regions suspended in a liquid network. This network is reduced in volume in response to hyperosmosis and forms small pockets between the gel-like regions.

Highly reversible potassium-ion intercalation in tungsten disulfide.

Rechargeable potassium-ion batteries (PIBs) show promise beyond Li-ion technology in large-scale electrical-energy storage due to the abundance and low cost of potassium resources. However, the intercalation of large-size K+ generally results in irreversible structural degradation and short lifespan to the hosts, representing a major obstacle. Here, we report a new electrochemical K+-intercalation host, tungsten disulfide (WS2), which can store 0.62 K+ per formula unit with a reversible capacity of 67 mA h g-1 and well-defined voltage plateaus at an intrinsically safe average operation potential of 0.72 V versus K/K+. In situ X-ray diffraction and ex situ electron microscopy revealed the underlying intercalation mechanism, a relatively small cell volume change (37.81%), and high reversibility of this new battery chemistry. Such characteristics impart WS2 with ultrahigh structural stability and a long lifespan, regardless of deep or fast charging. WS2 achieved record-high cyclability among chalcogenides up to 600 cycles with 89.2% capacity retention at 0.3C, and over 1000 cycles with 96.3% capacity retention and an extraordinary average Coulombic efficiency of 99.90% at 2.2C. This intercalation electrochemistry may open up new opportunities for the design of long-cycle-life and high-safety PIBs.