Ruthenium Oxide Research Articles

Redefining precision in cancer Treatment: A novel electrochemical approach using bimetal oxide composites for Niraparib quantification

Amidst the accelerating global surge in cancer incidences, there has been a parallel increase in worldwide efforts to propel the development of advanced therapeutic agents, and the role of poly(ADP-ribose)polymerase (PARP) inhibitors like Niraparib (NRP) has emerged as significant. NRP, approved by the FDA for treating certain ovarian cancers, requires precise and sensitive detection techniques to mitigate potential toxicities. Existing methods such as HPLC-UV, LC-MS/MS, and UPLC-MS/MS are often complex and expensive. In light of this, this study pioneered the development of a new electrochemical sensor utilizing a novel bimetal oxide composite to modify the bare glassy carbon electrode (GCE) to detect NRP efficiently. The bimetal oxide composite, comprised of ruthenium (IV) oxide (RuO2) and bismuth (III) oxide (Bi2O3), is designed to enhance the electrochemical performance of the electrode by offering superior redox (Faradaic) reactions and electrical conductivity. The implemented analytical strategy employed precision differential pulse voltammetry (DPV), conducted under rigorously controlled conditions to evaluate the sensor's performance. Subsequent assessments established a linear response range for NRP determination, spanning 0.1 to 9.39 µM, with a correlation equation denoted as I = 0.243CNRP + 0.261 and an associated coefficient of determination (R2) of 0.990. This allowed for the discernment of the limit of detection (LOD) at 0.037 µM and the limit of quantification (LOQ) at 0.12 µM for NRP. Significantly, the electrochemical sensor developed herein demonstrated robust efficacy in quantifying NRP in pharmaceutical formulations and urine samples, affirming its potential application in clinical practice. This research heralds a new era in the analytical pursuit of cancer therapeutics, providing an accessible, cost-effective, and reliable alternative for detecting and monitoring Niraparib, thereby contributing to the broader landscape of personalized oncology treatment.

Interfacial Interaction between the Ruthenium(IV) Oxide Cluster and Graphitic Carbon Nitride Governing the Photocatalytic Activity

Interfacial Interaction between the Ruthenium(IV) Oxide Cluster and Graphitic Carbon Nitride Governing the Photocatalytic Activity

Hydrous ruthenium oxide quantum dots anchored on carbon nanocages for Zn-ion hybrid capacitors

Zn-ion hybrid capacitors (ZICs) are a novel and promising electrochemical energy storage system, while exploring high-performance cathode materials is essential for the development of ZICs. Herein, we propose hydrous ruthenium oxide quantum dots (RuO2 QDs) anchored on porous carbon nanocages (PCNCs) as a new cathode material for ZICs. For the RuO2 QDs@PCNCs material, hydrous RuO2 QDs with a small size of 2–3 nm uniformly disperse on the PCNC support, providing large electrode–electrolyte interface for electrochemical reactions and abundant active sites for ion storage. Consequently, the RuO2 QDs@PCNCs cathode material displays desirable electrochemical performance in ZICs, including a large capacity of 224 mAh g−1 at 0.4–1.8 V, superior rate capability (showing 156 mAh g−1 capacity even at a large current of 20 A g−1) and good stability during a long-term cycling test over 20,000 cycles, significantly superior to currently-reported cathode materials for ZICs. An ultrahigh energy density of 180 Wh/kg is achieved for the RuO2 QDs@PCNCs cathode-based ZICs. Mechanism investigations point out the capacitive behavior-dominated and Zn2+/H+ co-participated charge storage process with fast electrochemical kinetics for the RuO2 QDs@PCNCs cathode in ZICs. This work not only provides a new choice for high-performance cathodes but also enriches the electrochemical theory of ZICs.

Economical electrochemical process for PAHs removal form offshore produced water

In this work, produced water (PW) from offshore exploration was electrochemically oxidised utilising ruthenium oxide (Ti/RuO2) anode in a lab-scale electrolytic batch cell. Electrolysis time, starting pH, and current density (CD) have all been examined for their effects. The sum of initial concentrations of 16 priority PAHs in PW was 160 g/dm3. At optimum conditions, including CD of 10 mA/cm2, pH 6, and electrolysis time of 4 h, maximum PAHs removal was 98 %. The CD, starting pH, and electrolysis duration were all optimised using the RSM-based Box-Behnken (BBD) experimental design. The trials findings demonstrated that the quadratic model, based on BBD, was appropriate for the data (P value > 0.0001), and the suggested model was supported by a high R-squared value. The polynomial regression model was chosen as the best fit model for optimization in the current investigation based on ANOVA. Low probability values and the model's F-values suggested that the elimination of PAHs is important. According to the findings, electrocatalytic oxidation with a Ti/RuO2 anode is a potentially effective method for removing PAHs from aqueous solutions.

Nanostructured Pt@RuOx catalyst for boosting overall acidic seawater splitting

In the domain of acidic water splitting, designing bifunctional catalysts that marry high activity with enduring stability is a formidable challenge. Herein, we have constructed platinum-containing ruthenium oxide nanoparticles (Pt@RuOx NPs) to achieve excellent overall water splitting performance in acidic electrolytes. Pt@RuOx NPs demonstrate exceptional catalytic activity for both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in acidic seawater, requiring overpotentials of only 20 and 157 mV, respectively to achieve a current density of 10 mA cm−2. Furthermore, in 0.5 M H2SO4, this catalyst exhibits high HER (19 mV) and OER (236 mV) catalytic activities. The two-electrode water splitting system composed of bifunctional Pt@RuOx NPs requires cell voltages of only 1.442 and 1.465 V to deliver a current density of 10 mA cm−2 in acidic seawater and 0.5 M H2SO4. Remarkably, this catalyst displays remarkable stability in the water splitting process. It is shown that the introduction of Pt could augment oxygen vacancies and enhance catalytic activity significantly. The synergy between Pt and Ru further contributes to the improved performance. Additionally, we have observed that acidic seawater holds distinct advantages for acidic water splitting, along with a thorough exploration of the relationship between Cl− concentration and catalytic performance. This study not only provides a strategy to improve the catalytic activity and stability of ruthenium-based catalysts for water splitting in acidic environments, but also unveils the promoting effect of Cl− on the catalytic activity in acidic water splitting.

Molten Salt-Derived RuO2 Nanocrystals and Nanowires: Unveiling Correlations of Morphology, Microstructure, and Electrocatalytic Performance.

Ruthenium oxide (RuO2), due to its comparable binding energy with *H and cost-effectiveness against Pt, has emerged as a pivotal electrocatalyst for oxygen evolution reaction (OER). In the present study, RuO2 nanocrystals (NCs) and nanowires (NWs) were obtained by a molten salt process and the morphology, crystal structure, and local bonding features were examined by using electron microscopy and X-ray absorption spectroscopy. From the electrochemical measurement, both RuO2 NCs and NWs exhibit favorable stability and activity toward oxygen evolution reaction in an alkali medium, althought NCs exhibit higher activity, which is likely attributed to the larger surface area and the high local structural disorder. The theoretical calculation reveals that RuO2 NWs with a primary (110) orientation show a higher overpotential due to its d-band center's proximity to the Fermi level versus (101). The present work suggests that the molten salt process could be an efficient method for producing metal oxide catalysts with tailorable geometry and performances.

Room‐Temperature Aerobic Oxidation of Amines to Nitriles over Ruthenium Oxide Supported on CeO2 Derived from MOFs

AbstractHeterogenous BPDC−RuO2−CeO2 catalyst derived from Ce−BPDC MOFs can successfully enable the oxidation of amines to nitriles under mild conditions (1 atm O2, H2O as a solvent, room temperature). The catalytic system has the good compatibility with benzylic and aliphatic amines. Lewis acid‐base pairs [Ru−O−Ce−Vö] formed by the combination of acidic oxygen vacancy and basic oxygen pair Ru−O−Ce on the surface of the catalyst is the key factor for the catalytic activity. The mechanical experiments indicate that amines adopt the step‐by‐step dehydrogenation process to nitriles in this transformation. Moreover, the catalyst could be recycled up to six times without the evident loss of catalytic activity and the change of morphology.

Ruthenium Oxide Clusters Immobilized in Cationic Vacancies of 2D Titanium Oxide for Chlorine Evolution Reaction

The development of dimensionally stable anodes (DSAs) has made the chlorine evolution reaction (CER) the most important industrial anode reaction since the 1960s. However, the preparation of DSA depends on the extensive use of precious metals, Ru and Ir, which are expensive and scarce. Herein, a cationic defect adsorption–oxidation anchoring strategy to immobilize oxidized sub‐nano ruthenium clusters on 2D low‐crystallinity titanium oxide (2D TiOx) substrate is reported. Through the metal oxide−support interaction, the 2D TiOx alters the electronic structure of ruthenium oxide (RuOx), improving its activity, selectivity, and stability for CER. Specifically, the mass activity of the RuOx/2D TiOx electrode is 26.5 and 143.5 times higher than that of the state‐of‐the‐art commercial RuO2 and DSA, respectively, at an overpotential of 100 mV. Moreover, the selectivity of the RuOx/2D TiOx electrode to CER is approximately 96.5%, and it exhibits remarkable durability lasting for over 210 h. Therefore, the 2D TiOx substrate holds significant potential for improving the dispersion, active site density, and atomic utilization of oxidized sub‐nano noble metal clusters.

Facile synthesis of ultrafine iron-cobalt (FeCo) nanocrystallite-embedded boron/nitrogen-codoped porous carbon nanosheets: Accelerated water splitting catalysts

Designing two-dimensional (2D) porous carbon nanosheets is expected to boost the water splitting efficiency of low-cost iron (Fe) and cobalt (Co)-based catalysts. Nevertheless, the aggregations, tedious preparation procedures, and expensive precursors for synthesizing 2D porous carbon nanosheets have hindered their widespread application. Herein, for the first time, we developed a low-cost method for large-scale and rapid synthesis of the three-dimensional (3D) hierarchically porous architectures self-assembled by the ultrafine FeCo nanoparticles embedded and boron/nitrogen-codoped 2D porous carbon nanosheets (denoted as FeCo@BNPCNS). The optimal FeCo@BNPCNS-900 exhibited abundant porous channels, a large surface area, and vast carbon edges/defects. Therefore, 8.10 at% electrochemically active boron (B)/nitrogen (N) centers were doped into the porous carbon nanosheets. In an alkaline solution, the optimal FeCo@BNPCNS-900 nanosheets revealed excellent hydrogen evolution reaction (HER) electrocatalytic activity, surpassing commercial 20 wt% Pt/C. For instance, the HER potential at 10 mA cm−2 [-50.6 mV vs. reversible hydrogen electrode (RHE)] of FeCo@BNPCNS-900 was even 19.3 mV more positive than that of commercial 20 wt% Pt/C (-69.9 mV vs. RHE). Meanwhile, its oxygen evolution reaction (OER) catalytic activity was just a little worse than ruthenium oxide (RuO2). The water electrolysis cell of FeCo@BNPCNS-900 nanosheets just required a small voltage of 1.589 V for full water splitting to achieve 10 mA cm−2, even 70.3 mV more negative than that of the state-of-the-art 20 wt% Pt/C||RuO2 benchmark (1.660 V) with outstanding stability. The perfect 3D hierarchically porous and honeycomb-like architecture, abundant porous channels/mesopores, and uniformly dispersed electrocatalytically active sites on FeCo@BNPCNS-900 nanosheets were responsible for the outstanding water splitting performance. Finally, this study provides an efficient strategy for the large-scale, rapid, and low-cost synthesis of 2D porous carbon nanosheets without using any template, surfactant, or expensive precursors.

Unravel the mechanism of d-orbital modulation and oxygen vacancy in cerium-doped RuO2 catalysts for acidic oxygen evolution reaction

Ruthenium (Ru) and its compounds with abundant d-orbital electrons are considered as potential candidates to replace commercial iridium-based catalysts for proton exchange membrane water electrolysis. However, the low corrosion resistance of ruthenium oxide in acidic conditions seriously hinders their large-scale application. Heteroatom doping can modulate the local bonding environment and electronic structure, and becomes a practical means to promote RuO2 in acid oxygen evolution reaction (OER). Here, we report Ce dopants in high-performance and durable Ce-RuO2 catalysts during acidic OER. Significantly, the Ce-RuO2 had high OER activity with a small overpotential of 191 mV (10 mA·cm−2), which was better compared with RuO2 (229 mV) and commercial RuO2 (351 mV). Theoretical analysis showed Ce in Ce-RuO2 had a lower peak at the Fermi level, indicating the adsorption capacity of oxygen-containing species is weaker than that of Ru. The introduction of Ce significantly impacts the d orbital, causing a positive shift in the d band of Ru, and raises the peak of Ru to the Fermi level, which promotes electron transfer. Furthermore, the rate-determining step for OER on the RuO2 (110) surface is the conversion of O to OOH, and the lower reaction energy of Ce-RuO2 than that of RuO2 (0.31 vs. 0.77 eV) demonstrates the thermodynamic advantage of Ce-doped RuO2 over pristine RuO2.

“Energizing bacterial sensing: Unveiling new horizons with Ti2CN-ionic liquid triboelectric nanogenerator”

Triboelectric nanogenerator provides efficient harvesting of electrical energy from the ambient mechanical energy for sustainable self-powered systems. This study describes the development of the Titanium carbonitride (Ti2CN)-Ionic liquid (IL)-based TENG system for powering the bacterial sensing system. Monitoring water safety against waterborne bacterial infection is crucial to eliminate bacterial disease outbreaks. Herein, the Mannose-binding lectin acts as a recognition element to target the pathogen-associated molecular patterns for the real-time onsite detection of Gram-positive and Gram-negative bacteria. The sensor comprising of the Mannose-binding lectin (MBL) immobilized on the Ruthenium oxide (RuO2) nanoparticle loaded bovine serum albumin (BSA) modified electrode. Taguchi orthogonal array optimized the factors involved in the performance of the sensor. Unlike the conventional bacterial detection strategies, this system requires only 20 min of incubation time and can detect E.coli, S.aureus and B.cereus whole-cell bacteria which proved this sensor could screen the bacterial concentration with a detection limit of 1.42–1.67 CFU mL−1 and a dynamic range of 101 to 105 CFU mL−1. The real-time analysis carried out in waster water samples ensured the reliability of the sensor and this strategy could further be used without any further instrumentation in future.

Surface chemistry regulation on particle-support interaction of ruthenium and Cr-Fe oxides for selective oxidation of 5-hydroxymethylfurfural

Surface chemistry regulation on particle-support interaction of ruthenium and Cr-Fe oxides for selective oxidation of 5-hydroxymethylfurfural

BaRuO3 coated Ti plate as an efficient and stable electro-catalyst for water splitting reaction in alkaline medium

Water splitting using an electrochemical device to produce hydrogen fuel is a green and economic approach to solve the energy and environmental crisis. The realistic design of durable electro-catalysts and their synthesis using a simplistic technique is a great challenge to produce hydrogen by water electrolysis. Herein, we report a stable highly active barium ruthenium oxide (BRO) electro-catalysts over Ti plate using a soft chemical method at low temperature. The synthesized material shows facile hydrogen evolution reaction (HER) as well as oxygen evolution reaction (OER) in alkaline medium with over-potentials of 195 mV and 300 mV, respectively at a current density of 10 mA cm−2. The excellent stability lasts for at least 24 h without any degradation for both the HER and OER at the current density of 10 mA cm−2, inferring the practical applications of the material toward production of green hydrogen energy. Certainly, the synthesized catalyst is capable adequately for the overall water splitting at a cell voltage of 1.60 V at a current density of 10 mA cm−2 with an impressive stability for at least 24 h, showing a minimum loss of potential. Thus the present work contributes to the rational design of stable and efficient electro-catalysts for overall water splitting reaction in alkaline media.

Understanding Catalytic Mechanisms and Cathode Interface Kinetics in Nonaqueous Mg-CO2 Batteries.

We leverage first-principles density functional theory (DFT) calculations to understand the electrocatalytic processes in Mg-CO2 batteries, considering ruthenium oxide (RuO2) as an archetypical cathode catalyst. Our goal is to establish a mechanistic framework for understanding the charging and discharging reaction pathways and their influence on overpotentials. On the RuO2 (211) surface, we found reaction initiation through thermodynamically favorable adsorption of Mg followed by interactions with CO2. However, we found that the formation of carbonate (CO32-) and oxalate (C2O42-) intermediates via the activation of CO2 at the catalytic site is thermodynamically unfavorable. We predict that MgC2O4 will form as the discharge product due to its lower overpotential compared to MgCO3. However, MgC2O4 is thermodynamically unstable and is expected to decompose into MgCO3, MgO, and C as final discharge products. Through Bader charge analysis, we investigate the covalent interactions between intermediates and catalyst sites. Moreover, we study the electrochemical free energy profiles of the most favorable reaction pathways and determine discharge and charge overpotentials of 1.30 and 1.35 V, respectively. Our results underscore the importance of catalyst design for the cathode material to overcome performance limitations in nonaqueous Mg-CO2 batteries.

Misoriented high-entropy iridium ruthenium oxide for acidic water splitting.

Designing an efficient catalyst for acidic oxygen evolution reaction (OER) is of critical importance in manipulating proton exchange membrane water electrolyzer (PEMWE) for hydrogen production. Here, we report a fast, nonequilibrium strategy to synthesize quinary high-entropy ruthenium iridium-based oxide (M-RuIrFeCoNiO2) with abundant grain boundaries (GB), which exhibits a low overpotential of 189 millivolts at 10 milliamperes per square centimeter for OER in 0.5 M H2SO4. Microstructural analyses, density functional calculations, and isotope-labeled differential electrochemical mass spectroscopy measurements collectively reveal that the integration of foreign metal elements and GB is responsible for the enhancement of activity and stability of RuO2 toward OER. A PEMWE using M-RuIrFeCoNiO2 catalyst can steadily operate at a large current density of 1 ampere per square centimeter for over 500 hours. This work demonstrates a pathway to design high-performance OER electrocatalysts by integrating the advantages of various components and GB, which breaks the limits of thermodynamic solubility for different metal elements.

Microwave abetted nano-hybrids driven high performance in catalytic, energy storage, and photovoltaic applications using RuO2–ZnO nano-hexagons anchored spheres

This work for the first time explores the pristine ruthenium oxide (RuO2) and RuO2 – zinc oxide (ZnO) nano-hexagons anchored spheres (RuO2–ZnO NHA – S) prepared via simpler microwave assisted route. NHA – S possessed 3.71 eV of band gap energy. It has a mixed crystallinity pattern based on tetragonal (space group: P42/mnm) and hexagonal (space group: P63mc), which are attributable to the presence of pristine RuO2 and ZnO. Morphologically, the developed nano-hybrid existed as the network of nano-spheres attached to nano-hexagons with varied extent of agglomeration. The electro-catalytic performance of this sustainable nano-hybrid was assessed for generation of oxygen and hydrogen through water splitting. As a bifunctional nano-catalyst, this material expressed greater affinity towards pure hydrogen production with of lower overpotential (ηHER) and Tafel slope values of 129 mV and 62.5 mV dec−1, respectively. Nano-hybrids embellished electrode achieved an outstanding specific capacitance of 834 F g−1 inside 0.1 M NaCl. While minimal equivalent series resistance (Rs) of 0.78 Ω indicated higher conductivity. As interface materials inside perovskite solar cells, they improved transferal of holes to hole extraction layer from absorber layer and reached an efficiency of 17.1% in comparison to pristine RuO2 gaining 11.63%.

Phase engineering oriented defect-rich amorphous/crystalline RuO 2 nanoporous particles for boosting oxygen evolution reaction in acid media

Imposing phase engineering to porous materials is promising to realize outperforming electrocatalytic performances by taking advantages of the merits of porous nanoarchitecture and heterophase structure. In this work, amorphous/crystalline ruthenium oxide (RuO₂) porous particles with rationally regulated heterophases are successfully prepared by integrating the phase engineering into the porous material synthesis. The resultant defect-rich amorphous/crystalline RuO₂ porous particles exhibit excellent electrocatalytic performance toward the oxygen evolution reaction, achieving a low overpotential of 165 mV at a current density of 10 mA·cm⁻² and a high mass activity up to 133.8 mA·cm⁻² at a low overpotential of 200 mV. This work indicates that the synergistic effect of amorphous/crystalline heterophase and porous structural characteristics enables RuO₂ to trigger a superior electrocatalytic activity.

Effect of Metal-Substitution within Ruthenium Oxide on Structure and Oxygen Evolution Activity and Stability

The development and utilization of proton exchange membrane water electrolyzers (PEMWEs) is hindered by the cost, activity, and stability of the oxygen evolution reaction (OER) electrocatalyst. Iridium oxide (IrOx) is currently the go-to OER electrocatalyst, as it has been shown to have relative high activity and stability when compared to other OER active catalysts. However, iridium is one of the rarest elements in the Earth’s crust, and therefore cost is a major limitation of iridium-based electrocatalysts. Ruthenium oxide (RuO2) is much lower cost and more active than iridium oxide; however, RuO2 it is unstable in acidic media and undergoes degradation over time. We investigated substituting niobium, tantalum, and zirconium, which are OER-stable metals, into RuO2 to improve the OER stability. Our study explored the effects of different metals and varied concentrations within RuO2 (Ru1-xMxO2, M = Nb, Ta, and Zr) on the structure, morphology, OER activity, and stability. The structure and morphology were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy, and scanning electron microscopy. Preliminary results from XRD showed observable phase separation at higher concentrations of Nb, Ta, and Zr and less phase separation at lower concentrations for Nb and Ta. There was no observable phase separation for Zr at lower concentrations. XRD peak shifts were observed and indicate the incorporation of the metal ions into the crystal structure of rutile RuO2. The OER activities and stabilities of Ru1-xMxO2 were measured using a rotating disk electrode configuration and compared with synthesized RuO2. Our preliminary results show that the OER activity and stability are strongly affected by the addition of the different metals and could be attributed to morphology and structural changes. Our findings help to further the development of lower cost, high activity, and increased stability OER electrocatalysts, which are crucial to the large-scale adoption of PEMWE’s.

Cobalt-Iron Cyanometallates as Active Components for Water Electrolysis through Oxygen Evolution in Acid Medium

Electrochemical water splitting (oxidation) leading to the oxygen evolution at anode and hydrogen generation at cathode is a topic of growing scientific and technological interest. The reaction provides not only means for producing oxygen but, more importantly, for generation of highly pure hydrogen, a carrier for storing renewable energy and further utilization in low-temperature fuel cells. Among important issues are choice of the catalytic material, its morphology and operating conditions including temperature, electrolyte, pH etc. In some cases of electrolysis cells, at cathode, the hydrogen evolution could be accompanied by CO2-reduction (to simple organic molecules), regardless of water oxidation, at anode.The suitability of polynuclear mixed-valence inorganic materials (e.g. polyoxometallates, infinite metal oxides, cyanometallates) for the preparation of thin electrocatalytic films on electrode surfaces has been recognized in recent years. Among such systems, Prussian Blue (iron hexacyanoferrate) and the metal-substituted (e.g. with Co, Ni, or Ru) analogues known as transition metal cyanometallates have received considerable attention owing to their physicochemical stability, well-defined redox transitions, counter-ion-sorption selectivity and catalytic electroactivity. In the present work, we explore Prussian-Blue-like cobalt(II,III) hexacyanoferrate(II,III) cocatalytic overlayers together with ruthenium oxide (conventional electrocatalysis) and tungsten oxide n-type semiconductors (photoelectrochemistry). While cobalt hexacyanoferrate has already been demonstrated to exhibit some activity toward oxidation of water under photoelectrochemical conditions, its intrinsic electrocatalytic activity is unclear, and it will be addressed during presentation.The mixed, or multi-layered, cyanometallates of cobalt, ruthenium and were fabricated through electrodeposition in the appropriate mixtures for modification. Special attention was paid to their morphological, structural properties and the presence of counter-cations (e.g., potassium or sodium, in addition to protons). Electrochemical measurements were performed using cyclic voltammetry, chronoamperometry and chronocoulometry. The systems’ structural modifications as well as their effect on the electroactivity of the catalytic systems towards the oxygen evolution reaction in acid media were addressed. It is noteworthy that some of the hybrid cobalt-ruthenium hexacyanoferrate compositions showed remarkable catalytic ability towards the oxygen evolution reaction in acid electrolyte. In other words, the cyanide-linked ruthenium-oxo species was used to promote oxygen evolution while cobalt hexacyanoferrates acted as stabilizing agents. The enhanced catalytic activities of the as-synthesized electrodes should also be attributed to such features as high population of hydroxyl groups and high Broensted acidity (due to presence of Ru or W oxo sites) and related fast electron transfers coupled to unimpeded proton displacements. The possibility of metal-metal interactions between nanosized metals (Co and Ru or Co and W) cannot be excluded.

Microwave-Assisted Sol-Gel Synthesis of High-Voltage Ruthenium-Doped LiFePO4 Cathodes for Solid-State Lithium-Ion Batteries

The demand for high voltage and high-capacity energy systems has grown due to increased use of portable electronics, electric vehicles, and grid energy storage systems. LiFePO4 (LFP) shows great promise as a cathode material due to its low cost, structural stability, safety characteristics, and low environmental impact. However, LFP cathodes possess a low Li-ion diffusion coefficient and poor electrical conductivity compared to oxide-based cathodes that are used currently. To make LFP competitive with oxide-based cathodes, LFP was modified to improve its characteristics. Doping of materials is a highly effective method for improving electrochemical characteristics in LFP cathodes. Ruthenium-doping of iron sites within LFP has shown positive effects in the promotion of Li-ion diffusion, reduction in band gap energies, and improved electrical conductivity. Previous studies have shown that ruthenium-doping at 0.01 moles has an increased specific capacity of 162 mAh g-1, better cycling characteristics, and reduced resistance compared to pristine LFP.1 Ruthenium doping levels above 0.02 moles have shown a decrease in specific capacity, cycling characteristics, and an increased resistance due to the formation of ruthenium oxide that disrupts the crystal lattice of LFP. In this study, LiFe1-xRuxPO4 (x= 0.01, 0.0075, and 0.005) and pristine LFP were prepared via microwave-assisted sol-gel synthesis to explore the effects of lower levels of ruthenium-doping on LFP electrochemical characteristics. Microwave synthesis was employed for reduced sintering time, beneficial effects on microstructure, and decreased cost. Samples were characterized via scanning electron microscopy, in-situ/ex-situ X-ray diffraction, energy dispersive X-ray spectroscopy, electrochemical impedance spectroscopy, and cyclic voltammetry.The authors acknowledge financial support from the NSF IUCRC program for the “Center for solid-state electric power storage” (#2052631) and support from the South Dakota Board of Regents for the “Governor’s Research Center (GRC) for electrochemical energy storage”.1.) Gao, Y.; Xiong, K.; Zhang, H.; Zhu, B. Effect of RU Doping on the Properties of Lifepo4/c Cathode Materials for Lithium-Ion Batteries. ACS Omega 2021, 6 (22), 14122–14129.