Electrolyte Concentration Research Articles

Tuning the Solvation Structure of a Weakly Solvating Cyclic Ether Electrolyte for Wide‐Temperature Cycling of Lithium‐Sulfurized Polyacrylonitrile Batteries

AbstractSulfurized polyacrylonitrile (SPAN) cathodes in high energy‐density Li‐metal batteries have garnered widespread interest owing to their good cycling stability and moderately high capacities. However, their application is hindered by the low prevalence of advanced electrolytes that can simultaneously mitigate polysulfide generation at the cathode and stabilize the Li‐metal anode. Here, a weakly solvating electrolyte is presented, employing a single solvent tetrahydropyran (THP). The solvation structure is effectively tuned by adjusting the salt concentration to stabilize both the Li‐metal anode and SPAN cathode. This approach enables stable cycling with high SPAN loadings (≈5 mg cm−2) and lean electrolyte contents (≈5 µL mgSPAN−1) across a wide temperature range: 0 °C, room temperature, and 50 °C. A pouch cell with a high SPAN loading and a low electrolyte‐to‐SPAN (E/SPAN) ratio of 3 µL mg−1 shows a stable 79.1% capacity retention after 40 cycles. Additionally, THP can be effectively employed in localized high‐concentration electrolyte (LHCE) systems to reduce the diluent‐to‐solvent ratio for greater LHCE viability. The study demonstrates the potential of weakly solvating solvents in Li‐SPAN batteries, offering a pathway for their practical application.

Performance optimisation of new basket-shaped TiO2 photoelectrodes in a photocatalytic fuel cell utilising the response surface method: dye elimination and energy generation

ABSTRACT Response Surface Methodology (RSM) simplifies fuel cell design and offers possibilities for process improvement, operating condition optimisation, and performance improvements. By identify the best design parameters, RSM helps create fuel cell systems that are dependable, economical, and efficient. Although RSM is widely applied in many domains, more studies are still needed evaluating photocatalytic fuel cell performance in dye removal and optimising the conditions of reactions. Using RSM (central composite design), the system's ability to remove Methyl Orange (MO) and produce energy was enhanced in this study. TiO2/Ti and CuO/Cu are employed in this system as the photoelectrodes. Effective optimised parameters on contaminant removal and energy production, including dye concentration, electrolyte concentration, and pH, were achieved as 23.31 mg/L, 0.1 M, and pH = 3, respectively. 71.26% MO dye was removed, and 0.63 V, 0.19 mA/cm2, and 0.037 mW/cm2 values were recorded for the open-circuit voltage (VOC), short-circuit current (JSC), and maximum power density (PMAX), respectively, under optimal conditions, which was very close to the experimental values. The analysis of variances for dye removal and VOC, JSC, PMAX, correlation coefficient, and adjusted correlation coefficient for the four mentioned responses indicated a strong correlation between the predicted and experimental data, confirming the model's accuracy.

Precise Construction of the Triple-Phase Boundary and Its Antiphosphate Poisoning Effect in the Confined Region.

As a critical component for the oxygen reduction reaction (ORR), platinum (Pt) catalysts exhibit promising catalytic performance in High-temperature-proton exchange membrane fuel cells (HT-PEMFCs). Despite their success, HT-PEMFCs primarily utilize phosphoric acid-doped polybenzimidazole (PA-PBI) as the proton exchange membrane, and the phosphoric acid within the PBI matrix tends to leach onto the Pt-based layers, easily causing toxicity. Herein, we first propose UiO-66@Pt3Co1-T composites with precisely engineered interfacial structures. The UiO-66@Pt3Co1-T exhibits an octahedral porous framework with uniform structural dimensions and even distribution of surface nanoparticles, which demonstrate superior ORR performance compared to commercial Pt/C. The unique structure and morphology of the composites also exhibit a favorable half-wave potential in different concentrations of phosphoric acid electrolyte, regulated by the phosphoric acid adsorption site and intensity.This finding suggests that the incorporation of Co could effectively modulate the Pt d-band center, thereby enhancing the ORR performance. Furthermore, the selective adsorption of phosphoric acid by ZrO2 enables precise control over the phosphoric acid distribution. Notably, the retention of the octahedral framework post high-temperature treatment facilitates the establishment of dual transport pathways for gases and protons, leading to a stable and efficient triple-phase boundary.

Electrolyte-Salts Regulated Hydrogen-Bonding Configuration and Interphase Formation Achieving Highly Stable Anode for Rechargeable Aqueous Sodium-Ion Batteries.

Hydrogen evolution reactions that cause the alkalization of aqueous electrolytes generally frustrate the structural stability and cycling performance of NaTi2(PO4)3/C anode material for rechargeable aqueous sodium-ion batteries (ASIBs). Herein, a novel highly concentrated electrolyte with a large hydrogen-evolution overpotential and hydroxide-capture ability is rationally established by incorporating a bifunctional Mg(Ac)2 additive into a concentrated NaAc aqueous solution. The highly concentrated electrolyte salts (4m NaAc+3m Mg(Ac)2) favor regulation on hydrogen-bonding configurations and kinetically shift the hydrogen evolution potential to a lower value of -1.37 V (vs Ag/AgCl). The Mg(Ac)2 additive plays particular roles in spontaneously capturing hydroxide ions generated during hydrogen evolution reactions on anode surfaces and simultaneously forming a protective Mg(OH)2-like interphase. As a result, the unique electrolyte significantly improves the structural stability and cycling performance of NaTi2(PO4)3/C anode (94.8% capacity retention after 100 cycles at 100 mA·g-1). The effect of salt concentration on hydrogen bonding configurations of aqueous electrolytes is investigated with Raman spectroscopy and FTIR spectroscopy. The interphase is identified by coupling EDS mapping, X-ray photoelectron spectroscopy, and X-ray diffraction. This work provides a new strategy for improving the cycling stability of aqueous sodium-ion batteries.

Solvent Polarity‐Induced Regulation of Cation Solvation Sheaths for High‐Voltage Zinc‐Based Batteries with a 1.94 V Discharge Platform

To address the challenge of low discharge platforms (<1.5 V) in aqueous zinc‐based batteries, highly concentrated salts have been explored due to their wide electrochemical window (~3 V). However, these electrolytes mainly prevent hydrogen evolution and dendrite growth at the anode without significantly enhancing voltage performance. Herein we introduce an approach by adjusting solvent polarity to regulate cation solvation sheaths in hybrid electrolytes, reducing Zn/Zn2+ oxidation potential and water activity. Through strong cation‐water coordination and hydrogen bonding between dimethylsulfoxide and water, the designed electrolyte, at a low concentration, achieves a broader electrochemical window (4 V) than conventional concentrated electrolytes. Using this electrolyte, a Zn/Zn battery showed an impressive cycle life of 4340 cycles, while a Zn/lithium manganate battery delivered a high discharge platform of over 1.9 V with exceptional cycling stability. A Zn‐based micro‐battery with a polyvinyl alcohol‐based hybrid electrolyte also achieved a record‐high discharge platform of 1.94 V. This work presents a promising strategy for developing low‐concentration electrolytes for high‐performance sustainable energy storage.

Solvent Polarity-Induced Regulation of Cation Solvation Sheaths for High-Voltage Zinc-Based Batteries with a 1.94 V Discharge Platform.

To address the challenge of low discharge platforms (<1.5 V) in aqueous zinc-based batteries, highly concentrated salts have been explored due to their wide electrochemical window (~3 V). However, these electrolytes mainly prevent hydrogen evolution and dendrite growth at the anode without significantly enhancing voltage performance. Herein we introduce an approach by adjusting solvent polarity to regulate cation solvation sheaths in hybrid electrolytes, reducing Zn/Zn2+ oxidation potential and water activity. Through strong cation-water coordination and hydrogen bonding between dimethylsulfoxide and water, the designed electrolyte, at a low concentration, achieves a broader electrochemical window (4 V) than conventional concentrated electrolytes. Using this electrolyte, a Zn/Zn battery showed an impressive cycle life of 4340 cycles, while a Zn/lithium manganate battery delivered a high discharge platform of over 1.9 V with exceptional cycling stability. A Zn-based micro-battery with a polyvinyl alcohol-based hybrid electrolyte also achieved a record-high discharge platform of 1.94 V. This work presents a promising strategy for developing low-concentration electrolytes for high-performance sustainable energy storage.

Unveiling the Electrostatically Driven Collapsing and Relaxation of Polyelectrolyte-Colloid Complexes: A Tunable Pathway to Colloidal Assembly.

Polyelectrolyte-colloid (PEC) complexes, ubiquitous across diverse fields, exhibit remarkable phase transitions, mimicking intricate biological assemblies. While the role of electrostatic forces in the PEC complex assembly is undeniable, achieving a holistic comprehension remains an elusive goal. This study unveils a fascinating phenomenon: the formation of highly collapsed coacervate structures in PEC complexes at elevated polyelectrolyte concentrations, followed by the swelling of complexes at even higher concentrations. Employing anionic silica colloids and cationic chitosan as a model system, small-angle X-ray/neutron (SAXS/SANS) elucidates the transition from a bead-on-a-necklace-like phase to a dense packed coacervate state (with volume fraction ∼0.62) until 3 wt % concentration of the polyelectrolyte. However, beyond 3 wt %, swelling of the dense collapsed assembly is observed. This structural evolution of PEC complexes as a function of chitosan concentration is attributed to the interplay of electrostatically driven interactions and the Donnan effect. Notably, the critical concentration for coacervation, Cs*, demonstrates a linear dependence on the initial colloid concentration. Interestingly, a complete expansion of the coacervate is observed at a high polyelectrolyte concentration, particularly for dilute colloid solutions (2 wt %). Furthermore, the addition of an electrolyte sheds light on the delicate interplay of forces. While a low electrolyte concentration partially screens charges, leading to a shift in phase diagram, higher concentrations trigger complete coacervate dissolution beyond the critical electrolyte concentration of 0.2 M, due to the complete screening of electrostatic charges.

Green Hydrogen Synthesis from Human Urine as Sustainable Bioenergy Resources

With the earths cry for help as pollution rate increases, researchers are faced with a common task of tackling pollution resulting from dependence on fossil fuel as well as delivering sustainable energy. Renewable energy resources such as solar, wind, hydro to mention a few are currently finding applications within the world energy mix but some limitations which range from meteorology of locations to expected maximum energy output attainable. Hydrogen, the most abundant element in the world stand chance of abating this problem. However conventional method of its producing, poses severe treat to the atmospheric environment with the release of oxides of carbon hence, referred as blue hydrogen. Contrarily, green hydrogen from human urine stands a more sustainable and environmentally friendly energy resource. This study was aimed to empirically model the synthesis of green hydrogen from urea in human urine by an electrolytic process. The synthesized hydrogen was characterized on physiochemical properties of conductivity, turbidity, pH, specific gravity and colour, while the precursor urine characterized on gender, exposure duration and storage temperature. The synthesis process was modelled using Microsoft excel solver for the overall cell energy or polarization curve model, the Faraday’s efficiency model and gas purity model at electrolyte concentrations of 25 wt./wt., 30 wt./wt. and 35 wt./wt. of potassium oxide (buffer} to urea over a five-temperature interval range of 45 to 85 oC. Findings revealed that the gas produced was 99.88% hydrogen at the cathode. Also, hydrogen produced increased with increase in electrolyte concentration and moderate temperature with optimal conditions at 35 w/w electrolyte concentration and 65 oC. However, the minimum cell voltage was 2.06 V at 85 oC and 35 w/w electrolyte concentration. With an exception of the Faraday’s efficiency model at 30 wt./wt. electrolyte concentration across the system’s operating temperature range yielding an R2 value of 0.711, all the models yielded coefficient of determination values in the range of 0.96 and 0.99, indicating good fit for the alkaline urine electrolysis for green hydrogen synthesis from human urine.

Advances in the understanding of selective CO2 reduction catalysis

AbstractThe electrochemical synthesis for value‐added chemicals and fuels via carbon dioxide reduction reaction (CO2RR) offers an effective route to close the anthropogenic carbon cycle and store renewable energy. Currently, the copper‐based catalyst is still the only choice for generating various CO2RR species beyond two electron products. However, the wide range of CO2RR products generated on copper leads to low selectivity, and their low concentrations in electrolytes pose great costs in the downstream purification process and significantly challenge the scalability of this technology. To make this technology economically viable, enhancing product selectivity is crucial. In this review, we identify the primary CO2RR species and discuss the latest insights into the reaction mechanisms controlling CO2RR selectivity. Then, we examined factors that affect CO2RR selectivity. Emphasizing these factors in catalyst design, we highlight the importance of advanced technologies to expand our knowledge and prospects for the future of the CO2RR.

Formulating Electrolytes for 4.6 V Anode-Free Lithium Metal Batteries

High-voltage initial anode-free lithium metal batteries (AFLMBs) promise the maximized energy densities of rechargeable lithium batteries. However, the reversibility of the high-voltage cathode and lithium metal anode is unsatisfactory in sustaining their long lifespan. In this research, a concentrated electrolyte comprising dual salts of LiTFSI and LiDFOB dissolved in mixing solvents of dimethyl carbonate (DMC) and fluoroethylene carbonate (FEC) with a LiNO3 additive was formulated to address this challenge. FEC and LiNO3 regulate the anion-rich solvation structure and help form a LiF, Li3N-rich solid electrolyte interphase (SEI) with a high lithium plating/stripping Coulombic efficiency of 98.3%. LiDFOB preferentially decomposes to effectively suppress the side reaction at the high-voltage operation of the Li-rich Li1.2Mn0.54Ni0.13Co0.13O2 cathode. Moreover, the large irreversible capacity during the initial charge/discharge cycle of the cathode provides supplementary lithium sources for cycle life extension. Owing to these merits, the as-fabricated AFLMBs can operate stably for 80 cycles even at an ultrahigh voltage of 4.6 V. This study sheds new insights on the formulation of advanced electrolytes for highly reversible high-voltage cathodes and lithium metal anodes and could facilitate the practical application of AFLMBs.

Performance analysis of wire-electrochemical discharge cutting of glass material

The present study investigated the feasibility of micro-cutting in glass material by using Electrochemical Discharge Machining (ECDM) Process. Glass possesses outstanding properties that make it a versatile with widely used in a diverse range of applications. Because of its tendency to fracture brittle during machining, glass is typically processed in its liquid or viscous state to manufacture precise and high-quality parts. Machining glass with good dimensional accuracy is a challenging task due to its fragile nature. Therefore, researchers have recognized the very appropriate technique for machining glasses with precision. The Wire-Electrochemical Discharge Machining (WECDM) has been identified as the most economical and efficient technique for fabricating micro slits in thin glass samples. In the present work, an in-house setup for WECDM was developed and the feasibility of the developed configuration was examined. Two different thicknesses of glass specimen have been considered for experimentation for checking the quality of cut and it is found that thinner specimen possesses good quality cut. The regression model has been developed to find a relationship between input and response parameters. The developed regression model was reasonably well fitted with the observed values where applied voltage 55V, 15% by wt. electrolyte concentration and 70% duty cycle were the most influencing parametric combinations among others. Further mixed electrolytes have shown excellent performance up to a certain concentration in terms of Material Removal Rate (MRR). This study reveals that optimal capillary action, influenced by surface tension and electrolyte concentration, is crucial for consistent sparking and efficient material removal in WECDM.

Perfluorooctanoic Acids (PFOA) removal using electrochemical oxidation: A machine learning approach

The urgent need to eliminate Perfluorooctanoic Acid (PFOA) has positioned electrooxidation (EO) as a key solution for pollutant degradation. This study evaluates several machine learning (ML) models, including K-Nearest Neighbors (KNN), Decision Tree (DT), Random Forest (RF), Gradient Boosted Decision Trees (GBDT), and Deep Learning (DL), to predict EO efficiency in PFOA removal. Using 10-fold cross-validation, the RF model outperformed others with a root mean square error (RMSE) of 7.7 and a correlation coefficient of 0.965, demonstrating its robustness and accuracy across diverse operational settings. Feature importance within the RF model was analyzed using Gini impurity and Mean Decrease in Accuracy (MDA). Electrolysis Time consistently emerged as the most influential factor in both analyses, underscoring its pivotal role in providing extended exposure of PFOA molecules to reactive species at the electrode surfaces. The study also found strong agreement between Gini and MDA in identifying Current Density and Anode Material as critical factors, although MDA placed slightly more emphasis on Anode Material. Differences between Gini and MDA were more pronounced in the ranking of Electrolyte Type and Concentration, with MDA assigning higher importance to Electrolyte Concentration. In contrast, the Water Matrix was consistently ranked as the least important factor. The strong concordance between Gini and MDA highlights the reliability of the RF model in identifying key drivers of electrochemical degradation. Overall, this work contributes significantly to the advancement of pollutant degradation technologies, presenting a reliable ML-based tool for environmental remediation efforts.

Water-Based Polyurethane Dispersions: A Detailed Analysis of the Particle Charge Using Soft and Hard Particle Model.

Water-based polyurethane dispersions (PUDs) show a characteristic dependency of the electrophoretic mobility on the electrolyte concentration, which can be investigated by hard and soft particle models. For this purpose, additional information can be obtained by determining particle charges and electrostatic potentials. PUDs with different contents of an intrinsic ionic stabilizer and various polyol components were synthesized according to the acetone process. The particle charge was characterized by potentiometric acid-base titration, and the data of the titration curve were fitted assuming multiple functional groups with adaptable acid strengths. To investigate the electrostatic potentials, electrophoretic mobilities were measured as a function of electrolyte concentration and analyzed by soft and hard particle theory. Acid-base titration experiments indicated that not all detected ionic groups are located on the surface but are partly arranged inside the polymer particle, as evidenced by a significant decrease of the corresponding effective dissociation constant. The evaluation of the titration data and the electrokinetic experiments showed that the soft particle model of Ohshima is not suitable to reflect the actual particle charge. In contrast, the hard particle model can describe the measured electrophoretic mobility of the dispersions very well if the relaxation effect is taken into account. The dependency of the corresponding zeta potentials on the electrolyte concentration can be excellently modeled assuming a constant surface potential ψ0 and distance of the shear plane xs. Reasonable results are obtained for both parameters with only minor differences between the PUD series. Nonetheless, the electrokinetic surface charge densities calculated with respect to the surface potential are lower than expected from the titration results. Although our results indicate a more complex charge distribution in a peripheral layer, the hard particle model currently shows the best description of the electrokinetic behavior of the PUDs.

Propensity of hydroxide and hydronium ions for the air-water and graphene-water interfaces from abinitio and force field simulations.

Understanding acids and bases at interfaces is relevant for a range of applications from environmental chemistry to energy storage. We present combined abinitio and force-field molecular dynamics simulations of hydrochloric acid and sodium hydroxide highly concentrated electrolytes at the interface with air and graphene. In agreement with surface tension measurements at the air-water interface, we find that HCl presents an ionic surface excess, while NaOH displays an ionic surface depletion, for both interfaces. We further show that graphene becomes less hydrophilic as the water ions concentration increases, with a transition to being hydrophobic for highly basic solutions. For HCl, we observe that hydronium adsorbs to both interfaces and orients strongly toward the water phase, due to the hydrogen bonding behavior of hydronium ions, which donate three hydrogen bonds to bulk water molecules when adsorbed at the interface. For NaOH, we observe density peaks of strongly oriented hydroxide ions at the interface with air and graphene. To extrapolate our results from concentrated electrolytes to dilute solutions, we perform single ion-pair abinitio simulations, as well as develop force-field parameters for ions and graphene that reproduce the density profiles at high concentrations. We find the behavior of hydronium ions to be rather independent of concentration. For NaOH electrolytes, the force-field simulations of dilute NaOH solutions suggest no hydroxide adsorption but some adsorption at high concentrations. For both interfaces, we predict that the surface potential is positive for HCl and close to neutral for NaOH.

Low‐Temperature Sodium–Sulfur Batteries Enabled by Ionic Liquid in Localized High Concentration Electrolytes

AbstractLow ionic migration and compromised interfacial stability pose challenges for low‐temperature batteries. In this work, we discovered that even with the state‐of‐the‐art localized high‐concentration electrolytes (LHCEs), uncontrolled Na electrodeposition occurs with a huge overpotential of &gt;1.2 V at −20 °C, leading to cell failure within tens of hours. To address this, we introduce a new electrolyte category that incorporates an ionic liquid as a key solvation species. Diverging from traditional LHCEs, the IL‐tailored LHCE facilitates an anion–solvent‐molecules exchange within the solvation sheath between Na+ and organic cations at low temperatures. This behavior reduces solvation cluster size and strengthens Na+–anion coordination, which proves instrumental in enabling fast ionic dynamics in both the bulk liquid and at the interface. Therefore, durable Na electrodeposition and shuttle‐free, 0.5 Ah sodium–sulfur pouch cells are achieved at −20 °C, for the first time, surpassing the limitations of typical LHCEs. This tailoring strategy opens a new design direction for advanced batteries operating in fast‐charge and wide‐temperature scenarios.

Free Fatty Acids and Biochemical Changes in Iraqi patients with Chronic Renal Failure

Chronic renal failure (CRF) is progressive irreversible destruction of kidney tissue by disease which, if not treated by dialysis or transplant, will result in patient's death. This study was carried out on 30 patients (17 male and 13 female) with chronic renal failure. The aim of this research was studied the changes in the level of total protein ,albumin, calcium ,ionized calcium, phosphorous , iron ,ALP, LDH ,CK and FFA in patients with CRF before and after hemodialysis .The obtained results have been compared with 30 healthy subjects as control group (18male and 12 female). The results showed that there was significant increase in the level of calcium ,ionized calcium, phosphorous ,iron ,ALP,LDH,CK and FFA ,while there was a significant decrease in the level of total protein ,albumin before hemodialysis comparison to control group . Non significant changes was observed in the level of total protein ,albumin, calcium ,ionized calcium, phosphorous and significant increase in the level of iron ,ALP,LDH,CK and FFA after hemodialysis as compared to control group. This study shows significant positive correlation between FFA and each of albumin and total protein in pre and post-dialysis patients ,and a significant positive correlation with calcium and non significant with ionized calcium in pre-dialysis patients where as there were non significant correlation with calcium and a significant negative correlation with ionized calcium in post-dialysis patients. The conclusion of this study is hemodialysate composition (concentration of electrolytes, free –ionized calcium and some other plasma constituents), the increase concentration of other biochemical changes after renal dialysis because of amissibility a much of amounts of body fluids, and the change in acidosis status may be affect on the correlation between FFA and other parameters used in this study.

Chitin Nanowhisker/Gold Nanocluster Hybrids with an Excellent Dispersion Stability via Poly(ethylene glycol) Grafting.

Hybrid nanoparticles composed of chitin nanowhiskers (ChNWs) and gold nanoclusters (AuNCs) having an improved stability were prepared. The grafting of monomethoxypoly(ethylene glycol) (mPEG) and subsequent surface adsorption of AuNCs enabled the steric stabilization of ChNW/AuNC hybrids. mPEGs with terminal formyl groups and diethylacetal protecting groups were grafted via in situ deprotection and reductive amination with the surface amino groups (SAGs) of ChNWs. The treatment of chitin with a 30% sodium hydroxide solution improved the SAG contents of the ChNWs obtained from acid hydrolysis, resulting in an enhancement in mPEG grafting. The obtained sterically stabilized ChNW/AuNC hybrids exhibited remarkable dispersion stability at higher AuNC and electrolyte concentrations.

A Comprehensive Study on the Parameters Affecting Magnesium Plating/Stripping Kinetics in Rechargeable Mg Batteries

AbstractMg metal anode‐based battery is a more sustainable, lower cost, and higher energy density alternative to Li‐ion. However, this battery chemistry also faces several challenges associated with the high charge density of Mg2+, including achieving high reversibility and low voltage hysteresis for Mg metal plating/stripping. While significant improvements are achieved in last decades, they involve rather complex electrolyte formulations and/or Mg salts difficult to produce, and the use of unpractical substrates such as platinum. Here, significant improvement in terms of Mg plating kinetics is achieved in electrolytes containing commercial magnesium bis(trifluoromethanesulfonyl)imide salt (Mg(TFSI)2) by using titanium substrate with similar crystal structure and lattice parameter as Mg leading to lower nucleation overpotential. Low salt concentration electrolyte and addition of dibutyl magnesium (Mg(butyl)2) also enable the formation of thinner interphase, richer in solvent based decomposition products, further improving Mg plating kinetics. This work highlights the complex role of Mg(butyl)2, often considered as a simple drying agent, and how it impacts ion solvation favoring the mobility of electroactive cationic species, paving the way toward better electrolyte design with improved cation transference number.

Soft ionic atmosphere model for molar conductivity, diffusion coefficient and viscosity in concentrated electrolytes

Soft ionic atmosphere model for molar conductivity, diffusion coefficient and viscosity in concentrated electrolytes

Clustering Based on Laboratory Data in Patients With Heart Failure Admitted to the Intensive Care Unit.

Heart failure (HF) is a common condition that imposes a significant burden on healthcare systems. We aimed to identify subgroups of patients with heart failure admitted to the ICU using routinely measured laboratory biomarkers. A large dataset (N = 1176) of patients with heart failure admitted to the ICU at the Beth Israel Deaconess Medical Center in Boston, USA, between June 1, 2001, and October 31, 2012, was analyzed. We clustered patients to identify laboratory phenotypes. Cluster profiling was then performed to characterize each cluster, using a binary logistic model. Two distinct clusters of patients were identified (N = 679 and 497). There was a significant difference in the mortality rate between Clusters 1 and 2 (50 [7.4%] vs. 109 [21.9%], respectively, p < 0.001). Patients in the Cluster 2 were significantly older (mean [SD] age = 72.35 [14.40] and 76.37 [11.61] years, p < 0.001) with a higher percentage of chronic kidney disease (167 [24.6%] vs. 262 [52.7%], respectively, p < 0.001). The logistic model was significant (Log-likelihood ratio p < 0.001, pseudo R2 = 0.746) with an area under the curve of 0.905. The odds ratio for leucocyte count, mean corpuscular volume (MCV), red blood cell (RBC) distribution width, hematocrit (HcT), lactic acid, blood urea nitrogen (BUN), serum potassium, magnesium, and sodium were significant (all p < 0.05). Laboratory data revealed two phenotypes of ICU-admitted patients with heart failure. The two phenotypes are of prognostic importance in terms of mortality rate. They can be differentiated using blood cell count, kidney function status, and serum electrolyte concentrations.