Pure SiO2 Research Articles

Enhanced photocatalytic removal of methyl orange dye employing SiO2/Mn2O3 based nanocatalyst under visible light

Surface water contamination by dye pollutants is a global environmental concern. The treatment of effluent from textile waste using metal oxide-based photocatalysts is a widely employed approach owing to its efficacy and simplicity. Herein, the synthesis and fabrication of novel visible radiation receptive manganese oxide and mesoporous silica nanocomposites (Mn2O3/SiO2) is described. Surface morphology of nanocomposites using scanning electron microscopy (SEM) displayed spherical shaped agglomerated structure. The chemical composition of nanocomposites was examined by using energy dispersive x-ray (EDX) analysis respectively indicating the presence of respective elements. Structural analysis was carried out by using XRD spectroscopy, while optical properties were evaluated by employing UV–visible spectroscopy. The photocatalytic activity of pure Mn2O3 and SiO2 nanoparticles as well as their nanocomposites with two different ratios Mn2O3/SiO2 (1:3) and Mn2O3/SiO2 (3:1) were evaluated by using methyl orange (MO) as a model dye. The band gap energy of Mn2O3/SiO2 (1:3) and Mn2O3/SiO2 (3:1) nanocomposite was 2.39 eV and 1.69 eV respectively. The nanocomposites exhibited improved photocatalytic efficiency as compared to pure nanoparticles as a function of pH and mixing ratio. For instance, at pH 7.0, Mn2O3/SiO2 (1:3) nanocomposite has depicted maximum degradation efficiency of 68 % for degradation of MO as compared to Mn3O4/SiO2 (3:1) nanocomposite, Mn3O4 and SiO2 nanoparticles. However, at pH 2.0 Mn2O3/SiO2 (3:1) nanocomposite had shown maximum degradation efficiency of 99 % as compared to Mn2O3/SiO2 (1:3), Mn2O3 and SiO2 nanoparticles. The degradation reaction followed pseudo first order kinetics. At pH 7.0, the rate constant values of nanocomposites i.e. Mn2O3/SiO2(1:3) and Mn2O3/SiO2(3:1) comes out to be 4.68 × 10−3 min−1 and 2.49 × 10−3 min−1 respectively. At pH 2.0, the rate constant values calculated for Mn2O3/SiO2(1:3) nanocomposite and Mn2O3/SiO2(3:1) nanocomposite was 4.91 × 10−3 min−1 and 1.24 × 10−2 min−1 respectively. The easy fabrication of these nanocomposites coupled with facile tuning of their properties make them suitable contenders for efficient dye degradation in wastewater treatment.

Impact of Harmonic Voltage on the Partial Discharge Properties of Eco-Friendly Nanofluid

The Insulation is crucial in transformers to maintain electrical isolation between components and windings, ensuring safe and efficient operation. Mineral oil acts as both insulation and coolant in transformers. It is a substance that does not naturally degrade and can persist in the environment for an extended period if accidentally released. Therefore, Sunflower oil is used as a substitute for mineral oil. However, harmonic distortion is a common issue in power systems, leading to increased dielectric loss and partial discharge activity, ultimately causing insulation failure and equipment damage. Hence, it is vital to analyze the partial discharge performance of pure Sunflower oil under varying harmonic AC voltages to ensure the reliable operation of electrical devices. The study examines the partial discharge characteristics of a sunflower oil-based nanofluid under harmonic AC voltages, which is a blend of pure sunflower oil and SiO2 nanoparticles. Two nanofluid mixtures were created, one with a 0.01% mass ratio and the other with 0.05% sunflower oil. Various PD characteristics were evaluated, including Partial Discharge significance, starting voltage, duration of increase, maximum amplitude, Phase-Resolved PD sample, and frequency and time graphs of the Partial Discharge signal. All tests were carried out under IEC regulations. A comparison was made between the outcomes of Nano blended sunflower oil and natural sunflower edible oil. Experiments were conducted on partial discharges in Sunflower oil using specific harmonic superimposed AC Voltages, utilizing the third and fifth harmonics. The findings reveal that: a) PDIV value decreases with increasing harmonic order when using AC voltage with superimposed harmonics, b) PD characteristics are closely related to the voltage waveform, and the addition of Silica to sunflower oil results in reduced PD amplitude, pulse duration, and time duration compared to pure sunflower oil.

Effect of MgO on solidification crystallisation behaviour of high SiO2 content MnO–SiO2–Al2O3-based inclusions in Si–Mn-killed steel

Aiming at avoiding the formation of high-hardness crystalline phase in inclusions, the effect of MgO on the solidification crystallisation behaviour of high SiO2 content MnO–SiO2–Al2O3-based inclusions was investigated. The results showed that the high SiO2 content MnO–SiO2–Al2O3 inclusions precipitated the pure SiO2 phase during the solidification process. With the increase of MgO content in inclusions, the content of the SiO2 phase decreased continuously, while the MgSiO3 phase began to precipitate and the content increased gradually. Besides, 20 wt.% MgO content inclusions first precipitated the Mg2SiO4 phase, and the MgSiO3 phase was formed in the subsequent solidification process. Thermodynamic calculation results indicated that the beginning of crystallisation temperature first decreased and then increased with the increase of MgO content in inclusions. However, the calculation results were partially different from the experiment results, because inclusions became the undercooling system during solidification and led to crystallisation hysteresis. The increase of MgO content in inclusions decreased the content of bridging oxygen and resulted in the depolymerisation of complex network structures, which promoted the crystallisation of inclusions. Moreover, the crystalline phase formed in inclusions transformed along the route of “SiO2 phase–MgSiO3 phase–Mg2SiO4 phase” with the increase of MgO content in inclusions.

Kinetics of formation, microstructure, and properties of monolithic forsterite (Mg2SiO4) produced through solid-state reaction of nano-powders of MgO and SiO2

The synthesis of forsterite can be challenging because the initial oxides react slowly and undesirable compounds like enstatite (MgSiO3) can form instead of forsterite (Mg2SiO4). Although several methods have been developed to overcome these challenges, the synthesis of forsterite using the solid-state reaction of nanopowders has not been investigated. This study aims to explore the possibility of producing forsterite by reacting MgO and SiO2 nano-powder. The initial oxides were wet ball milled, dried, and reaction sintered. Spectroscopy and microscopy methods were used to analyze the formed phases and study the formation kinetics. The density, coefficient of thermal expansion (CTE), and hardness of sintered samples were measured using a densimeter, a dilatometer, and a hardness tester, respectively. The results demonstrated that it is possible to synthesize forsterite by solid state reaction of pure MgO and SiO2 nano-powders. The reaction between the two compounds begins at a temperature as low as 860 °C and leads to the formation of forsterite by a two-step formation mechanism. The first reaction involves the reaction of MgO and SiO2 to form enstatite, and the second one produces forsterite as a result of enstatite reacting further with MgO. The activation energy values ranged from 1028.89 to 1105.655 kJ/mol for the formation of forsterite, and from 456.316 to 488.08 kJ/mol for the formation of enstatite. Monolithic forsterite was completely formed at a low temperature of 1200 °C for a relatively short duration of 2 h. The sample sintered at 1400 °C for 2 h, had a density of 2.96 g/cm3, a Vickers hardness of 7.64 GPa, and a coefficient of thermal expansion of 10.24 × 10−6/K measured in the temperature range of 200–1300 °C.

Superhydrophilic antireflection films with excellent optical and mechanical performance for perovskite solar cells

SiO2-based antireflection (AR) films can obviously improve the transmittance of the glass cover on the solar cells. Nevertheless, it’s still challenging to fabricate SiO2 films in a facile way with great antireflective properties, high hardness and good weather resistance to ensure their long-term use in outdoor environments. To solve this problem, a double-layer broadband SiO2 antireflective film with high transmittance increase and excellent mechanical properties was successfully prepared via an acid-catalyzed sol–gel method using polyethylene glycol (PEG) as pore-forming agent. The porous PEG2000-modified SiO2 films were selected as the outer layer for coating onto the pure SiO2 film to form double-layer SiO2 films with graded refractive index. When the mass ratio of PEG2000 to TEOS was 40 %, the obtained film showed the highest transmittance increase of 3.03 % in the wavelength range of 380–1100 nm and a high hardness of 3H. After applied to the perovskite solar cell, a significant enhancement of 1.19 % in photoelectric conversion efficiency (PCE) was achieved compared to the solar cell covered with bare substrate. Furthermore, the water contact angle (WCA) was also reduced to 6° while that of pure SiO2 film was 51.3°, endowing the double-layer SiO2 film superhydrophilic and anti-fogging performance. After the weather resistance test, the transmittance loss of the film was only 0.38 %. Therefore, this work demonstrated that the use of an appropriate amount of pore-forming agent PEG and the double-layer graded refractive index structure can enhance the transmittance of acid-catalyzed SiO₂ films, while maintaining high hardness and good weathering resistance for perovskite solar cells.

Effect of desert-sand replacing pure SiO2 on crystallization, densification and properties of cordierite glass-ceramic

Idle desert sand was utilized to replacing pure SiO2 in raw materials to synthesize cordierite glass-ceramics. The effects of desert sand addition on sinterability, phase transformation, microstructure, and mechanical and thermal properties of the glass-ceramics were studied. Results show that glass transition temperature and the crystallization temperatures of glass to μ-cordierite and further to α-cordierite were all monotonously decreased with an increase of the replacement from 10 wt% to 90 wt%. Densification of the glass powder compacts started from 900 °C and was improved with increasing the replacement of desert sand and sintering temperature. The highest bending strength of 133.6 MPa and hardness of 936.7 HV were occurred at 90 wt% replacement when sintered at 1000 °C and 1100 °C for 2 h respectively; the lowest thermal expansion coefficient of 1.92 × 10−6/°C was achieved by a 50 wt% replacement and sintering at 1100 °C for 2 h. Desert sand addition not only introduces main compositions of SiO2, Al2O3, and MgO but also introduces nucleation agents of Fe2O3 and TiO2 and fluxes of Na2O, K2O, and CaO. These impurities had significant effect on improvement of the crystallization, densification, and properties of products. This eliminates the need for nucleation agents and fluxes that are necessary in the case of using pure oxides and minerals as raw materials.

Role of alumina particles in chemical-mechanical synergies in ruthenium polishing

Abrasive particles are usually considered to only play a "mechanical wear" role in the metal chemical mechanical polishing (CMP) process, neglecting their influence on chemical reactions. This study reveals the chemical role of Al2O3 particles in ruthenium (Ru) CMP by comparing the properties and polishing performance of Al2O3-SiO2 mixed slurry and pure SiO2 slurry. Several testing methods are used to investigate the mechanical and chemical actions of Al2O3 particles, including particle size distribution, Zeta potential, electrochemical reaction kinetics, oxide layer property and hydroxyl radical detection test. The results indicate that Al2O3 particles enhance the mechanical action by reducing the Zeta potential, and promote the chemical action by catalyzing hydrogen peroxide to produce hydroxyl radical (Fenton-like reaction) on Ru surface. These increase the material removal rate of Ru CMP with mixed slurry by nearly 5 times, while the surface roughness decreases by 60 %. The mechanism of chemical reaction promoted by increasing the hydroxyl radical concentration on Ru surface is confirmed from the aspects of increased corrosion current, oxide layer thickness and proportion of higher-valence Ru oxide (RuO2) in the oxide layer. Among them, the thickened oxide layer is a significant factor contributing to the substantial improvement in the material removal rate of Ru and the reduction in surface roughness. This study enhances the understanding of the chemical-mechanical synergistic mechanism of abrasive particles in metal polishing and elucidates the principle of this mechanism on promoting material removal and surface quality. It also provides new research ideas and theoretical guidance for efficient and high-quality metal polishing.

SYNTHESIS AND CHARACTERIZATION OF NANOSILICA (SiO2) VOLCANIC ROCK OF MOUNT BATUR IN BALI

This research was conducted to synthesize and characterize silica minerals (SiO2) from volcanic rocks in the active volcano in Bali, namely Mount Batur. The synthesis carried out on five different color variants of this rock sample is by the coprecipitation method which begins with the process of taking rock samples on Mount Batur, crushing the rock until it becomes powder with a size of 100 mesh, washing with distilled water and drying, immersing the rock powder in the solution. 2 M HCl for 12 hours, then the results of the soaking were reacted again with 7 M NaOH solution as a hydrolysis process to obtain pure SiO2 in the sample. In the form of sodium silicate precursor (Na2SiO3), the sample was titrated with a 2 M HCl solution to obtain silica gel which was then washed and dried until amorphous silica powder was produced. The results of the XRF analysis showed that the SiO2 mineral content in the sample after going through the synthesis process was 94.9% and the Si element was 89.9%. The XRD characterization results show that the phase formed from the sample has a quartz structure with the highest peak at an angle of 2θ = 23.07o, then decreases and levels out at an angle of 2θ = 32.94o which is characteristic of an amorphous structure and with a silica grain size of 8.47 nm – 8.65 nm.

High-temperature CO2 sorption over Li4SiO4 synthesized from diatomite: study of sorption heat and isotherm modeling.

The Li4SiO4 seems to be an excellent sorbent for CO2 capture at post-combustion. Our work contributes to understanding the effect of the natural Algerian diatomite as a source of SiO2 in the synthesis of Li4SiO4 for CO2 capture at high temperature. For this purpose, we use various molar % (stoichiometric and excess) of calcined natural diatomite and pure SiO2. To select the best composition, CO2 sorption isotherms at 500°C on the prepared Li4SiO4 are obtained using TGA measurements under various flows of CO2 in N2. The sorbent having 10% molar SiO2 in diatomite (10%ND-LS) exhibits the best CO2 uptake, probably due to various factors such as the content of the different secondary phases. A comparative study was performed at 400 to 500°C on this selected 10%ND-LS and those with stoichiometric composition obtained with diatomite and pure SiO2. The obtained isotherms show the endothermic character of CO2 sorption. In addition, the evolution of isosteric heat highlights the nature of the involved CO2/Li4SiO4 interactions, by considering the double-shell mechanism. Finally, the experimental sorption isotherms are confronted with some well-known adsorption models to explain the phenomenon occurring over our prepared sorbents. Freundlich and Jensen-Seaton models present a better correlation with the experimental results.

Nitrogen plasma treated cotton fabrics coated with SiO2 followed by RGO deposition for water purification process

Experimental investigations have been carried out to modify the surface properties of Cotton fabrics using low temperature DC glow discharge nitrogen plasma. Plasma treatment is an eco-friendly, dry and clean process over wet chemical methods and does not suffer from any environmental and health concerns [1]. The important plasma parameters such as power and working pressure are kept constant with various treatment times (5, 15, 30, and 60 mins). The plasma-treated cotton fabrics are optimized by XRD, FTIR, and SEM. A comparative study has been done for the untreated and different treated fibers. Pure SiO2 is coated on untreated and nitrogen plasma treated cotton fabrics by sputtering method. The samples are coated for different sputtering times (10 and 30 min). Finally, Reduced Graphene Oxide (RGO) is coated on plasma treated SiO2 deposited fabrics. RGO is prepared by modified hummers methods [2]. Our results provide a way to develop a filter for water purification.

Assessment of thermohydraulic performance and entropy generation in an evacuated tube solar collector employing pure water and nanofluids as working fluids

This study conducts a numerical comparison of the thermal performance of three distinct working fluids (pure water, TiO2, and SiO2 water-based nanofluids) within an evacuated tube solar collector using Computational Fluid Dynamics. The study evaluates thermohydraulic performance alongside global and local entropy generation rates, while considering variations in solar radiation values and inlet mass flow rates. Results indicate that nanofluids demonstrate superior performance under low solar radiation, exhibiting higher outlet temperatures, velocities, thermal efficiency, and exergy efficiency compared to pure water. However, at the higher solar radiation level, the efficiency of SiO2 water-based nanofluid diminishes due to its impact on specific heat. Furthermore, the entropy generation analysis reveals significant reductions with TiO2 water-based nanofluid in all the phenomena considered (up to 79 %). The SiO2 nanofluid performance aligns closely with pure water under high radiation value. This investigation offers valuable insights into the utilization of nanofluids in solar collectors across diverse operating conditions, emphasizing their pivotal role in enhancing overall performance.

Insight into the photodegradation of o,p'-dichlorodiphenyltrichloroethane in a broad spectrum of irradiation light

Photolysis is the main pathway for the degradation of persistent organic pollutants (POPs). Most investigations, however, have been limited to the ultraviolet or visible region, and the reaction mechanism of infrared (IR) light is still unclear. In this study, the photodegradation of o,p'-dichlorodiphenyltrichloroethanes (o,p'-DDT) on the silica (SiO2)/air interface under different irradiation light sources was systematically investigated. Interestingly, for the first time, effective degradation of o,p'-DDT under IR light irradiation was observed, which was ascribed to the anti-Stokes Raman scattering process of SiO2. Moreover, desert sands could also serve as a vector for the photodegradation of o,p'-DDT. The lower removal efficiency of desert sands compared to pure SiO2 was a combined effect of differences in Fe3+ component and SiO2 content. It is worth noting that direct photodegradation plays a dominant role in the photodegradation of o,p'-DDT on SiO2. Besides, indirect photodegradation resulted mainly from •OH (25.0%), O2•− (6.9%), and 1O2 (5.6%) generated in the reaction system. In addition to hydroxylation and dechlorination products, the formation of four novel silicon-based products was observed, which resulted from the direct reaction of silyl radicals with o,p'-DDT. This study revealed that the specific Raman scattering effect of SiO2 played a vital role in the self-purification process of POPs upon SiO2-based environmental matrices. The light-mediated decontamination system upon SiO2 constructed in this study could provide critical information for addressing POPs contamination on sands.

Fabrication of Superhydrophobic Coating (SiO<sub>2</sub>/PDMS) by a Simple Method

A simple and economical method for producing a superhydrophobic surface on a glass substrate is investigated. The surface composes of silica particles synthesized via a sol-gel method with an average particle size of 69.33 nm. Organosilan PDMS (FS-1200 silicon sealant) was used to reduce the surface energy of particles, which were then coated onto a glass substrate by dip coating. After coating, the substrate was dried for one hour at 60ºC in an oven to remove excess solvent. XRD, FE-SEM, FTIR, and contact angle (CA) measurement techniques were used to characterize silica particles and coated surfaces. The water contact angle (WCA) of pure SiO2 (NPs) was 86º indicating its hydrophilic qualities, while the contact angle of a superhydrophobic surface was 156º.

Hydrogen partitioning between stishovite and hydrous phase δ: implications for water cycle and distribution in the lower mantle

Water is transported into the deep mantle by subducting slabs, playing important roles in mantle dynamics and evolution. An aluminous hydrous mineral, phase δ with a main component of AlOOH, has been considered an important water carrier in the lower mantle. Recent studies reported that SiO2 stishovite can accommodate weight percent levels of water, indicating another important water carrier in the lower mantle. However, which mineral can mainly carry water is not clear yet. Recent hydrous phase relation studies reported that stishovite is depleted in alumina when coexisting with hydrous phase δ, in which water content of stishovite was not investigated. In this study, we investigated hydrogen partitioning between stishovite and hydrous phase δ at 24–28 GPa and 1000–1200 °C by means of Kawai-type multi-anvil press in combination with Fourier-transform infrared spectroscopy at ambient conditions on recovered samples. Fourier-transform infrared spectra of recovered stishovites showed that water contents of stishovite coexisting with hydrous phase δ were limited to up to ~ 500 ppm. This indicates that coexisting hydrous phase δ causes not only depletion in alumina but also in hydrogen in stishovite and therefore mainly transports water in a cold subducting slab. Once hydrous phase δ becomes thermally unstable, alumina and water contents in silica minerals are increased by the chemical reaction between SiO2 and AlOOH, and aluminous silica minerals such as stishovite and CaCl2-type phase will be a main water carrier in the lower mantle. Presence of small-scale seismic scatterers observed around 1900 km depth, which was considered to be caused by a transition from almost pure SiO2 stishovite to CaCl2-type phase, might also be able to be explained by the phase transition of stishovite coexisting with hydrous phase δ.

La doped silica aerogel as selective adsorbent for the desulfurization of model fuel

La doped silica aerogel composites (La2O3/SiO2-n) with different Si/La molar ratio were synthesized through sol-gel method and atmospheric drying technology, which were used to adsorb thiophenic compounds from model fuels. Compared with the pure SiO2 aerogel, the adsorption capacities of La2O3/SiO2-n obviously increased, owing to adding La species led to the appearance of the weak Lewis acid sites on the surface. The adsorption mechanism of La2O3/SiO2-n for thiophenics included the direct S-La bond and weak π-La acid-base interaction between La3+ and thiophenics, and the former was primary. Among La2O3/SiO2-n, the La2O3/SiO2-200 not only had the highest adsorption capacity for thiophene, up to 8.16 mg S/gads (i.e., 138.31 mg-S/mmol La), but also exhibited an excellent anti-aromatics competitive adsorption ability and a good regeneration performance. The adsorption kinetic and adsorption isotherms were well described by pseudo-second-order (PSO) and Langmuir models, respectively, indicating the adsorption of La2O3/SiO2-200 for TH was dominated by chemisorption, which was a spontaneous and endothermic process. The present of aromatics in model fuels had a slightly negative effect on the adsorption of La2O3/SiO2 for thiophene.

Production of hydrogen via water oxidation using mesoporous‐assembled SiO2@TiN nanocomposite electrocatalyst

AbstractElectrochemical water splitting is one of the promising approaches for the production of molecular hydrogen as well as to meet the clean and sustainable energy demand of the modern world. However, the key task for the research communities is to design a cost‐effective and efficient electrocatalyst to contribute positively to recent world crises. This study presents a novel SiO2@TiN nanocomposite and utilize it for oxygen evolution reaction (OER) as an electrocatalysts. The different techniques use for the characterization of SiO2@TiN nanocomposite. The electrochemical investigations encompass linear sweep voltammetry (LSV), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) which collectively yield critical parameters for assessing electrocatalytic performance. At a current density of 10 mAcm−2 the SiO2@TiN nanocomposite has a substantially lower overpotential of 256 mV compared to pure SiO2 and TiN. The composite also shows smaller tafel slope of 40 mV dec−1 as well as lower overpotential. The SiO2@TiN nanocomposite also demonstrates the enhanced redox activity as a result of its synergistic effect. Consequently, the increased electrical conductivity of TiN facilitates the attachment of metal oxides and more active sites are exposed to improve the OER activity of the fabricated materials.

Insights into the solid-liquid interface of ionic liquid-immobilized solid acid catalyst for isobutane alkylation

The hydrophobic surface modification of solid acids can modulate the interfacial behaviors for isobutane alkylation. Herein, the interfacial properties between isobutane/butene mixtures and immobilized chloroaluminate ionic liquids with different alkyl chain lengths (e.g., ethyl, butyl, hexyl, and octyl groups) on silica substrates were studied through molecular dynamics simulations. The immobilization of ILs leads to obvious aggregation of C4 reactants and improves molar ratio of isobutane to 2-butene (I/O) at the interface, e.g., SiO2-[EPIm][Al2Cl7] (I/O = 1.17) versus pure SiO2 (I/O = 0.77) systems. With the prolonged alkyl chain of cations, the interfacial thickness gradually increases, while the I/O molar ratio exhibits the opposite order. Despite the inhibited diffusion of C4 reactants by immobilized ILs, the relative diffusion of isobutane to 2-butene is improved as the alkyl chain of cations prolongs. The above information suggests that the immobilization of ionic liquids with butyl groups is a good choice for isobutane alkylation.

Mesoporous silica-amine beads from blast furnace slag for CO2 capture applications.

Steel slag, abundantly available at a low cost and containing over 30 wt% silica, is an attractive precursor for producing high-surface-area mesoporous silica. By employing a two-stage dissolution-precipitation method using 1 M HCl and 1 M NaOH, we extracted pure SiO2, CaO, MgO, etc. from blast furnace slag (BFS). The water-soluble sodium silicate obtained was then used to synthesize mesoporous silica. The resulting silica had an average surface area of 100 m2 g-1 and a pore size distribution ranging from 4 to 20 nm. The mesoporous silica powder was further formed into beads and post-functionalized with polyethyleneimine (PEI) for cyclic CO2 capture from a mixture containing 15% CO2 in N2 at 75 °C. The silica-PEI bead was tested over 105 adsorption-desorption cycles, demonstrating an average CO2 capture capacity of 1 mmol g-1. This work presents a sustainable approach from steel slag to cost-effective mesoporous silica materials and making CO2 capture more feasible.

A Scalable and Effective Strategy for Boosting the Initial Coulombic Efficiency of Silicon Suboxide Anode

Silicon suboxide (SiO x ) is one of the most attractive candidates for anode materials for high-energy-density lithium-ion batteries due to its high specific capacity and its relatively lower volume expansion than that of Si. However, its low initial Coulombic efficiency (ICE) seriously affects its practical applications. In this work, we demonstrate a scalable and effective strategy to enable a high ICE of the SiO x electrode through a MnO-assisted disproportionation reaction. The obtained Mn 2 SiO 4 –Si–SiO x @C (MSS@C) material shows a reduced lithium irreversible consumption in the first cycle. The Mn 2 SiO 4 phase can store lithium through a conversion reaction with a smaller volume change (33%) than SiO x , which helps to maintain the structural stability of MSS@C during cycling. Meanwhile, the metallic Mn nanoparticles generated from Mn 2 SiO 4 during the lithiation process facilitate electron conduction, thus improving the electrode reaction kinetics. Owing to the synergetic effects, the MSS@C material exhibits a higher ICE (79.51%) compared to 60.91% of pure SiO x , and a superior cyclic performance (832 mAh g −1 at 0.5 A g −1 after 350 cycles with a capacity retention of 90.4%). This work offers a new approach to increase the ICE while improving the electrode reaction kinetics and cycling stability of SiO x -based materials.

Difunctional Ag nanoparticles with high lithiophilic and conductive decorate on core-shell SiO2 nanospheres for dendrite-free lithium metal anodes

Lithium metal is an attractive and promising anode material due to its high energy density and low working potential. However, the uncontrolled growth of lithium dendrites during repeated plating and stripping processes hinders the practical application of lithium metal batteries, leading to low Coulombic efficiency, poor lifespan, and safety concerns. In this study, we synthesized highly lithiophilic and conductive Ag nanoparticles decorated on SiO2 nanospheres to construct an optimized lithium host for promoting uniform Li deposition. The Ag nanoparticles not only act as lithiophilic sites but also provide high electrical conductivity to the Ag@SiO2@Ag anode. Additionally, the SiO2 layer serves as a lithiophilic nucleation agent, ensuring homogeneous lithium deposition and suppressing the growth of lithium dendrites. Theoretical calculations further confirm that the combination of Ag nanoparticles and SiO2 effectively enhances the adsorption ability of Ag@SiO2@Ag with Li+ ions compared to pure Ag and SiO2 materials. As a result, the Ag@SiO2@Ag coating, with its balanced lithiophilicity and conductivity, demonstrates excellent electrochemical performance, including high Coulombic efficiency, low polarization voltage, and long cycle life. In a full lithium metal cell with LiFePO4 cathode, the Ag@SiO2@Ag anode exhibits a high capacity of 133.1 and 121.4 mAh/g after 200 cycles at rates of 0.5 and 1C, respectively. These results highlight the synergistic coupling of lithiophilicity and conductivity in the Ag@SiO2@Ag coating, providing valuable insights into the field of lithiophilic chemistry and its potential for achieving high-performance batteries in the next generation.