Reduction In Thermal Conductivity Research Articles

Enhancing thermoelectric properties of Ca3Co4O9 ceramics through oscillatory pressure sintering

Oscillatory Pressure Sintering (OPS) has been demonstrated to be a favorable manufacturing approach for the control of fine and uniform distribution of grains in various ceramic systems, which can lead to enhanced densification and thus improved physical and mechanical properties. In this study, OPS was utilized to prepare pure Ca3Co4O9 thermoelectric material. The results show that the electrical properties and thermoelectric properties of Ca3Co4O9 prepared by OPS are superior to those of samples sintered by conventional hot pressing (HP) without oscillation. This may be attributed to the better alignment of plate-like grains in the OPS samples, which increase electrical conductivity, and also the higher density of grain boundaries that enhance the phonon scattering and, thus, the reduction of thermal conductivity. This study suggests that a straightforward oscillatory pressure sintering approach can be utilized to obtain high-quality and high-performance thermoelectric materials without the need for doping, templating, or high-temperature sintering.

Extremely Low Lattice Thermal Conductivity and Significantly Enhanced Near-Room-Temperature Thermoelectric Performance in α-Cu2Se through the Incorporation of Porous Carbon.

In this work, a series of Cu2Se/x wt % porous carbon (PC) (x = 0, 0.2, 0.4, 0.6, 0.8, 1) composite materials were synthesized by ball milling and spark plasma sintering (SPS). The highly ordered porous carbon was synthesized by a hydrothermal method using mesoporous silica (SBA-15) as the template. X-ray diffraction results show that the incorporation of porous carbon induces a phase transition of Cu2Se from the β phase to the α phase. Meanwhile, the addition of porous carbon reduces the carrier concentration from 2.7 × 1021 to 2.45 × 1020 cm-3 by 1 order of magnitude. The decrease of the carrier concentration leads to the reduction of electrical conductivity and the increase of the Seebeck coefficient, which results in the enhancement of the power factor. On the other hand, the incorporation of porous carbon into Cu2Se increases the porosity of the composites and also introduces more interfaces between the two materials, which is evidenced by positron annihilation lifetime measurements. Both pores and interfaces greatly enhance phonon scattering, leading to extremely low lattice thermal conductivity. In addition, the decrease of electrical conductivity also causes a sufficient reduction in electronic thermal conductivity. Due to the above synergistic effects, the thermoelectric performance of the Cu2Se/PC composite is significantly enhanced with a maximum ZT value of 0.92 at 403 K in the Cu2Se/1 wt % PC composite, which is close to that of the Bi2Te3-based materials. Our work shows that α-Cu2Se has great potential for near-room-temperature thermoelectric materials.

Entropy engineering in transition metal sulfides for thermoelectric application

Transition metal sulfides have emerged as highly promising materials in thermoelectrics owing to their economic viability and sustainable characteristics. Herein, we developed entropy-engineered sulfides based on TiS2. The process of equal doping at Ti sites resulted in a notable reduction in lattice thermal conductivity due to point defects and phase segregation induced by entropy engineering; however, it also had a substantial detrimental effect on the Seebeck coefficient. Finally, by incorporating minor doping at Ti sites with Zr, Nb and Ta, each at a concentration of 1 at%, an impressive figure of merit of 0.38 was achieved at 625 K because minor doping was able to maintain the large Seebeck coefficient while simultaneously reducing the lattice thermal conductivity. This study not only illuminates the significant role of entropy engineering in reducing lattice thermal conductivity but also sparks interest in the potential of equivalent doping at sulfur sites for future investigations.

Coherent and incoherent phonon transport in periodic nitrogen-doped graphene

Nitrogen-doped graphene materials hold significant promise for diverse applications owing to their exceptional electrical properties and the tunability of thermal conductivity. Therefore, the non-equilibrium molecular dynamics simulations were used to explore the phonon transport properties of nitrogen-doped graphene nanoribbons. The findings indicate that periodic doping with a small quantity of nitrogen atoms can induce coherent phonon transport, thereby resulting in a substantial reduction in thermal conductivity. Our analysis delves into various phonon and energy transport parameters, including the phonon dispersion relation, group velocity, state density, participation rate, and spectral heat flow. Through this examination, we have elucidated the coexistence and transformation mechanisms of both coherent and incoherent phonon transport under different conditions. Furthermore, our findings revealed a notable trend: once the concentration of nitrogen atoms in the doped atomic layer reaches 37.5%, the reduction in thermal conductivity attains its maximum effectiveness. Beyond this concentration, further increases in the nitrogen atom concentration result in diminishing returns, rendering the reduction in thermal conductivity ineffective.

Reduction of thermal conductivity in carbon nanotubes by fullerene encapsulation from machine-learning molecular dynamics simulations

The carbon nano-peapod is a representative structure with interlayer van der Waals (vdW) interactions, in which encapsulated fullerene molecules play a critical role in modulating the transport properties of the carbon nanotubes (CNTs). In particular, their influence on the thermal transport characteristics has been the focal point of considerable attention. In this study, we trained an accurate machine learning potential for fullerene-encapsulated CNTs based on the efficient NEP model to investigate their thermal properties. Using equilibrium molecular dynamics simulation along with the spectral decomposition method for thermal conductivity, we find that the thermal conductivity of fullerene-encapsulated CNTs is roughly 55% lower than that of empty CNTs, aligning with experimental observations for CNT bundles with fullerene encapsulation [Kodama et al., Nat. Mater. 16, 892 (2017)]. The research suggests that weak vdW interactions between both the fullerene and CNTs, as well as between fullerene molecules themselves, hinder phonon propagation. The encapsulated fullerene contributes to an increase in phonon scattering within the CNTs, ultimately leading to a reduction in thermal conductivity. We utilized machine learning potential to investigate the structure of fullerene-encapsulated CNTs and their heat transport property. This approach provides valuable insights for performance research of complex systems featuring interlayer vdW interactions.

Enhancing thermoelectric performance through acid-treated NbFeSb: A versatile approach for sustainable energy conversion

Drop-casting has emerged as a promising and scalable technique for fabricating thermoelectric generators, suitable for energy harvesting and waste heat recovery applications. This study delves into the potential of thermoelectric drop-casting utilizing acid-treated NbFeSb, a half-Heusler material. The acid treatment notably reduces the particle dimensions of NbFeSb from a micro-scale to a nano-scale, thereby enhancing phonon scattering and diminishing thermal conductivity from 16 to 12 W/mK at room temperature. The formulation of the thermoelectric ink involves ethylene glycol as the solvent and polyvinylpyrrolidone (PVP) as an additive, meticulously optimized to enhance dispersion and rheological attributes. To systematically analyze the performances of the printed films, an investigation was conducted, varying the PVP concentration. Our findings indicate that a 20% PVP content yields the highest power factor, concurrently enhancing the Seebeck coefficient and electrical conductivity, while preserving reduction in thermal conductivity. The ink-printed films of acid-treated NbFeSb exhibited superior thermoelectric performance compared to pristine NbFeSb films, owing to the uniform distribution of nanoparticles and the absence of particle agglomeration. Furthermore, this study successfully fabricates a flexible thermoelectric generator (TEG) using acid-treated NbFeSb ink, demonstrating its potential integration into wearable devices and power generation systems. The TEG attains an open-circuit voltage of 88 mV across a temperature gradient of 40 K, with a peak output power of 8.1 mW. This study highlights the significant impact of thermoelectric drop-casting as an adaptable and efficient approach to enhance the thermoelectric performance of high-thermal-conductivity half-Heusler materials, opening new avenues for sustainable energy conversion technologies.

Combining the D3 dispersion correction with the neuroevolution machine-learned potential

Machine-learned potentials (MLPs) have become a popular approach of modeling interatomic interactions in atomistic simulations, but to keep the computational cost under control, a relatively short cutoff must be imposed, which put serious restrictions on the capability of the MLPs for modeling relatively long-ranged dispersion interactions. In this paper, we propose to combine the neuroevolution potential (NEP) with the popular D3 correction to achieve a unified NEP-D3 model that can simultaneously model relatively short-ranged bonded interactions and relatively long-ranged dispersion interactions. We show that improved descriptions of the binding and sliding energies in bilayer graphene can be obtained by the NEP-D3 approach compared to the pure NEP approach. We implement the D3 part into the gpumd package such that it can be used out of the box for many exchange-correlation functionals. As a realistic application, we show that dispersion interactions result in approximately a 10% reduction in thermal conductivity for three typical metal-organic frameworks.

Development of HFCVD apparatus for synthesizing diamond films with low thermal budget

The electrical power consumption, which is approximately equal to the thermal budget, accounts for the majority of the total cost to synthesize diamond films by the hot filament chemical vapor deposition (HFCVD) apparatus. In this study, two strategies, visualizing as certain additional parts in the apparatus, are proposed for reducing the thermal budget and synthesis cost. Detailed effects are proven by the finite volume method (FVM) simulation, temperature measurement and deposition experiments, demonstrating that the reduction of thermal conductivity of the worktable (by changing the worktable material) and the insertion of the circular ring copper shielding will significantly contribute to the reduction of the heat dissipation and substrate temperature rise. Influences of major filament parameters on substrate temperature values and distributions are then clarified, suggesting that in order to control the substrate temperatures in a similar and reasonable range in the modified apparatus, the best choice is to synchronously reduce the filament diameter and the electrical power, while retaining the filament temperature still in a high level (around 2200 °C). Finally, the energy saving ratios are as high as 28.4% (experimental apparatus) and 27.4% (commercial apparatus), and the substrate temperature distributions can also be improved, guaranteeing the uniformity of as-deposited diamond films on mass substrates.

Phonon resonance modulation in weak van der Waals heterostructures: Controlling thermal transport in graphene–silicon nanoparticle systems

The drive for efficient thermal management has intensified with the miniaturization of electronic devices. This study explores the modulation of phonon transport within graphene by introducing silicon nanoparticles influenced by van der Waals forces. Our approach involves the application of non-equilibrium molecular dynamics to assess thermal conductivity while varying the interaction strength, leading to a noteworthy reduction in thermal conductivity. Furthermore, we observe a distinct attenuation in length-dependent behavior within the graphene–nanoparticles system. Our exploration combines wave packet simulations with phonon transmission calculations, aligning with a comprehensive analysis of the phonon transport regime to unveil the underlying physical mechanisms at play. Lastly, we conduct transient molecular dynamics simulations to investigate interfacial thermal conductance between the nanoparticles and the graphene, revealing an enhanced thermal boundary conductance. This research not only contributes to our understanding of phonon transport but also opens a new degree of freedom for utilizing van der Waals nanoparticle-induced resonance, offering promising avenues for the modulation of thermal properties in advanced materials and enhancing their performance in various technological applications.

Diffuson‐Dominated and Ultra Defect‐Tolerant Two‐Channel Thermal Transport in Hybrid Halide Perovskites

AbstractOrganic‐inorganic hybrid halide perovskites show a unique two‐channel thermal transport through propagons and diffusons, largely affecting other energy carriers for opto‐ and thermoelectric applications. Taking CH3NH3PbI3 as a prototype, the impact of iodine vacancy point defects on the two‐channel thermal transport is investigated using theoretical calculations and experimental validations. This work finds that iodine vacancies suppress the thermal transport in the propagon channel significantly, but less in the diffuson channel. This results in a weaker reduction of the total thermal conductivity (TC) than that predicted by the classical Klemens model. The TC reduction in the diffuson channel is mainly attributed to the declined vibrational density of states. Moreover, low‐frequency diffusons transformed from propagons compensate the reduction of TC in the diffuson channel, resulting in a dominant contribution from the diffuson channel to the total TC, which is 55% to 85% for 0% to 6% vacancy concentration. CH3NH3PbI3 also shows ultra‐defect‐tolerant diffusonic thermal transport, ≈1–2 orders of magnitude lower than diamond in the defect sensitivity factor. This work shows both scientific insights into the new two‐channel thermal transport mechanism in complex material systems with disorder, and technological significance on halide perovskites for solar cell, light‐emitting diode, thermoelectric, and memristor applications.

Investigations on the performance of xanthan gum as a foam stabilizer and assessment of economic and environmental impacts of foam concrete production

The properties of foam concrete are greatly influenced by the quality of the foam used. The stability of the foam is a vital property that needs dire attention when selecting surfactant. This paper evaluates the role of Xanthan gum (XG) as an additive in the performance improvement of foam produced with two different surfactants, viz., Hingot (Natural surfactant) and Nonylphenol ethoxylate (NPE) (Synthetic surfactant). Different characteristics of foam and surfactant, such as initial foam density, foam drainage, foam bubble microstructure, surface tension, and viscosity of surfactants, are experimentally evaluated. Addition of XG results in a 10-fold increment in viscosity for both Hingot and NPE surfactant solutions. The above enhancement in viscosity results in a substantial reduction in bubble size and an increment in lamella thickness. Further, the reduced surface tension of Hingot surfactant also contributes to a significant reduction in the rate of bubble coalescence. Having studied the surfactant and foam behaviour, the next phase comprises studies on the influence of XG on consistency, setting behaviour, compressive strength, and thermal conductivity of foam concrete with two different densities, viz., 1000 kg/m3 and 1500 kg/m3. Results show that the addition of XG results in a reduction in consistency and an increase in demoulding time of foam concrete. Besides improvement in foam performance, a substantial increase in compressive strength and reduction in thermal conductivity of FC is also observed due to XG addition, indicating that foam bubble microstructure has a significant impact. The last phase involves the life cycle assessment (LCA) of the FC produced with the aforementioned surfactants, which is the first of its kind study that considers the impact of surfactants across various environmental categories. Results of the LCA analysis show that the total cumulative energy demand of preparation of 1 kg of Hingot solution is less than that of 1 kg of NPE surfactant solution. The environmental impact analysis also favours Hingot as a sustainable and economical alternative to NPE surfactant. Results of LCA analysis of FC indicate that foam concrete with 1000 kg/m3 performs better than AAC block and conventional clay brick. Furthermore, the studies highlighted that there is more scope for improving the performance of LCA of FC through using various mineral admixtures as replacement for cement.

Microstructure and thermoelectric properties of pristine and Al-doped ZnO ceramics fabricated by cost-effective and eco-friendly wet chemistry methods

ZnO has potential as a thermoelectric material for high-temperature applications, but its performance is limited by the strong interconnection between electrical and thermal transportation. In this study we proved that ZnO bulk samples produced from cost-effective and environmentally friendly nitrates via ultrasonic spray pyrolysis and modified chemical precipitation methods followed by spark plasma sintering, demonstrate significantly higher thermoelectric performance than those fabricated from commercially available ZnO powder. To further explore the potential of the developed chemical precipitation technique, we synthesized a series of Al-doped samples with a nominal composition of Zn1–xAlxO (x = 0.02, 0.04, 0.06). The substitutuion of Al into the ZnO structure led to two significant effects: (i) a partial substitution of Zn with Al boosts the power factor; (ii) the formation of the ZnAl2O4 spinel phase acting as scattering center for phonons in addition to the mass and strain fluctuations induced by the partial Zn-Al substitution, both leading to the thermal conductivity reduction. As a result, Al doping led to a threefold enhancement of the thermoelectric performance with zT value of ∼0.12 achieved at 1100 K for the Zn0.94Al0.06O sample.

Strain-Induced Defect Evolution for the Construction of Porous Cu2-xSe with Enhanced Thermoelectric Performance.

Superionic Cu2-xSe, with disordered and even liquid-like Cu ions, has been extensively studied as a high efficiency thermoelectric material. However, the relationship between lattice stability and microstructure evolution in Cu2-xSe under strain, which is crucial for its application, has seldom been explored in previous research. In this study, we investigate the impacts of hydrostatic compression strain on the microstructural evolution and, consequently, its implications for thermoelectric performance. Molecular dynamics (MD) simulations show that high hydrostatic compression strain could induce local diffusion of Cu ions and Se twin evolution, resulting in the breaking and reforming of Cu-Se dynamic bonds and the unstable Se sublattice. The subsequent annealing process of the destabilized structure promoted Se evaporation from the sublattice and resulted in lotus-seedpod-like pores. The reduced sound velocity and intensified phonon scattering, due to pores, lead to a reduction in the lattice thermal conductivity from 0.44 W m-1 K-1 to 0.24 W m-1 K-1 at 800 K, a decrease of approximately 45%, in the porous Cu1.92Se sample. These findings reveal the relationship between stability and defect evolution in Cu2-xSe under high hydrostatic compression, offering a straightforward strategy of defect engineering for designing unique microstructures by leveraging the instability in superionic conductor materials.

Phonon thermal transport in ferroelectric α-In2Se3 via first-principles calculations

Two-dimensional (2D) ferroelectrics are promising candidates in the field of microelectronics due to their unique properties such as excellent photoelectric responsiveness. However, the thermal properties of 2D ferroelectrics are less investigated. Here, the thickness dependent thermal conductivity in ferroelectric α-In2Se3 is systematically investigated by the first-principles method combined with the phonon Boltzmann transport equation. On this basis, the strain and oxidation effects on the thermal conductivity of monolayer α-In2Se3 is further studied. The calculation results show that the thermal conductivity has a significant reduction with decreasing film thickness or increasing tensile strain, and the anharmonic phonon–phonon scattering rate is the intrinsic mechanism for the reduction in thermal conductivity. On the other hand, the replacement of Se atoms by O atoms can achieve a bidirectional and wide-range (12×) tuning of thermal conductivity. The increase in specific heat and phonon group velocity is responsible for the thermal conductivity enhancement at high doping levels while that in phonon–phonon scattering rate is responsible for the thermal conductivity reduction at low doping levels. In all cases, acoustic phonons dominate the in-plane thermal transport behavior. These findings broaden our understanding of phonon transport and its control in ferroelectric semiconductor α-In2Se3.

Multifunctional GeMnTe2 Synergistically Optimizes Thermoelectric Properties of SnTe-In2Te3 Alloys.

SnTe-In2Te3 alloys ensure excellent electrical properties in the whole temperature region due to the resonant level. Nevertheless, temperature-sensitive resonance states and single phonon scattering restrict further improvement of thermoelectric performance. Consequently, it is anticipated that additional electrically independent scattering sources should be introduced to impede phonon transport. Here, the SnTe-In2Te3-GeMnTe2 alloy is prepared by further solidifying cubic GeMnTe2, which demonstrates multiple modulation effects. The highly redissolved Mn2+ promotes the valence band convergence, enhances the Seebeck coefficient at higher temperature, and balances the possible weakened resonance level effect at higher carrier concentrations, and a high average power factor (1.94 mW m-1 K-2) is realized over the entire temperature range. Additionally, compensatory vacancies, substitutions, and Ge/Mn precipitates are easily constructed with GeMnTe2 alloying, leading to a further reduction in lattice thermal conductivity, which reaches κl ∼ 0.6 W m-1 K-1 at 850 K. Ultimately, a high peak zT of ∼1.25 (850 K) and a zTave of 0.72 (300-850 K) are realized in (SnTe)2.91(In2Te3)0.03(Ge0.5Mn0.5Te)1.2, and the maximum thermoelectric conversion efficiency of ∼2.8% (ΔT ∼ 450 K) is achieved. The present results indicate multiple effects of GeMnTe2 in enhancing the thermoelectric performance of SnTe-In2Te3 alloys.

Improving thermal insulation of fired earth bricks with alfa plant and glass powder additives: Effects on thermo-physical and mechanical properties

This study focuses on investigating the thermal, physical, and mechanical attributes of a lightweight fired earth brick composed of clay and dune sand, stabilized with lime. The study explores the impact of incorporating alfa plant powder and glass powder, constituting 15% and 10% respectively, relative to the soil matrix weight. This addition aims to attain optimized thermal, physical, and mechanical characteristics. Employing the statistical software, Statgraphics, experimental designs were created and analyzed, allowing for optimizations. The outcomes demonstrated a notable reduction in thermal conductivity, up to 42.36% and 23.91%, with the inclusion of alfa plant powder and lime, respectively. However, this led to a decrement in physical and mechanical properties. Conversely, the introduction of glass powder led to a decrease of total water absorption rates by as much as 4.52%. Utilizing the statistical program, an optimal ratio of 10.26% alfa powder was suggested, resulting in a brick with a thermal conductivity of 0.384 W/m.K, a compressive strength of 8.561 MPa, and a total water absorption rate of 26.922%. These findings underscore the potential of incorporating alfa plant powder to enhance fired earth bricks, particularly in terms of thermal insulation. Additionally, it presents a sustainable and eco-friendly material technology.

Enhanced Thermal Conductivity of Single-Walled Carbon Nanotube with Axial Tensile Strain Enabled by Boron Nitride Nanotube Anchoring.

Thermal conductivity measurements are conducted by optothermal Raman technique before and after the introduction of an axial tensile strain in a suspended single-walled carbon nanotube (SWCNT) through end-anchoring by boron nitride nanotubes (BNNTs). Surprisingly, the axial tensile strain (<0.4 %) in SWCNT results in a considerable enhancement of its thermal conductivity, and the larger the strain, the higher the enhancement. Furthermore, the thermal conductivity reduction with temperature is much alleviated for the strained nanotube compared to previously reported unstrained cases. The thermal conductivity of SWCNT increases with its length is also observed.

Alkali activated materials with recycled unplasticised polyvinyl chloride aggregates for sand replacement

Incorporating recycled Unplasticised Polyvinyl Chloride (UPVC) aggregates into Alkali Activated Materials (AAMs) presents a promising approach to alleviate the environmental drawbacks associated with conventional recycling methods for UPVC. The distinctive characteristics of UPVC aggregates, as compared to natural sand, pose a challenge in the pursuit of enhancing the mechanical properties of composites. This research aims to achieve net-zero goals and promote circular economy principles by replacing traditional Portland cement (OPC) with low-carbon AAMs and natural aggregates with recycled unplasticised polyvinyl chloride (UPVC) which, accounts for 12% of global plastic production. Coarse and fine UPVC aggregates, measuring 4–6 mm and 0–2 mm, respectively, were incorporated into AAMs. An extensive array of tests was performed to assess their environmental benefits and overall performance enhancements. The results unveiled notable advantages in terms of thermal resistivity and resistance to chloride penetration in the UPVC-infused AAMs. Notably, mixtures containing 100% fine UPVC aggregates exhibited a remarkable 70% reduction in thermal conductivity (0.465 W/mk) when compared to the control. In mechanical assessments, composites containing fine UPVC aggregates surpassed those with coarse UPVC aggregates, showcasing promise for load-bearing applications. Substituting 30% of both fine and coarse UPVC aggregates with sand yielded impressive 7-day compressive strengths of 41 MPa and 35 MPa, respectively. Moreover, the utilisation of energy-dispersive X-ray spectroscopy confirmed the absence of chloride leaching after three months. The incorporation of UPVC waste aggregates led to a significant reduction in the carbon footprint of the tested AAMs. In conclusion, these composites offer an appealing and sustainable solution for both load-bearing and non-load-bearing structures.

Prototype of alveolar gypsum blocks with plastic waste addition for partition walls: Physico-mechanical, water-resistance and life cycle assessment

The development of eco-friendlier building products incorporating waste as an alternative to raw materials has become increasingly relevant within the construction industry. With this in mind, this study presents a prototype of an alveolar gypsum block for partition walls, wherein partial replacement of the binder (i.e. gypsum or cement) was made using two types of plastic waste (i.e. polypropylene- and nylon-based). Two plastic waste-containing composites, with contents considered as optimum in previous studies (AGB/PP/7.5–7.5 wt% polypropylene content; AGB/PA6/2.5–2.5 wt% nylon content), were produced and extensively analysed in comparison to a reference block. Physico-mechanical (bulk density, surface hardness, flexural and compressive strength), water permeability and thermal properties were evaluated and compared to commercially available counterparts. In addition, the prototypes’ environmental impact was determined by conducting a simplified life cycle assessment primarily based on the “Global Warming Potential” and “Embodied Energy” categories. The results showed a widespread improvement in the mechanical performance of plastic-containing blocks and more so for those reinforced with nylon fibres when compared to the reference product. Furthermore, notable reductions in thermal conductivity and water permeability were observed on the blocks due to the addition of plastic waste. Both types of blocks presented a slight environmental impact decrease because of the reduction of raw materials (i.e. gypsum). These findings are encouraging from a practical application point of view and may create a notable opportunity for replacing more frequently gypsum with polypropylene- or nylon-based wastes for alveolar blocks for building partition walls.

Lattice thermal conductivity of embedded nanoparticle composites: the role of particle size distribution

Nanoparticles embedded within a crystalline solid serve as impurity phonon scattering centers that reduce lattice thermal conductivity, a desirable result for thermoelectric applications. Most studies of thermal transport in nanoparticle-laden composite materials have assumed the nanoparticles to possess a single size. If there is a distribution of nanoparticle sizes, how is thermal conductivity affected? Moreover, is there a best nanoparticle size distribution to minimize thermal conductivity? In this work, we study the thermal conductivity of nanoparticle-laden composites through a molecular dynamics approach which naturally captures phonon scattering processes more rigorously than previously used analytical theories. From thermal transport simulations of a systematic variety of nanoparticle configurations, we empirically formulate how nanoparticle size distribution, particle number density, and volume fraction affect the lattice thermal conductivity. We find at volume fractions below 10%, the particle number density is by far the most impactful factor on thermal conductivity and at fractions above 10%, the effect of the size distribution and number density is minimal compared to the volume fraction. In fact, upon comparisons of configurations with the same particle number density and volume fractions, the lattice thermal conductivity of a single nanoparticle size can be lower than that of a size distribution which contradicts intuitions that a single size would attenuate phonon transport less than a spectrum of sizes. The random alloy, which can be considered as a single size configuration of maximum particle number density where the nanoparticle size is equal to the lattice constant, is the most performant in thermal conductivity reduction at volume fractions below 10%. We conclude that nanoparticle size distribution only plays a minor role in affecting lattice thermal conductivity with the particle number density and volume fraction being the more significant factors that should be considered in fabrication of nanoparticle-laden composites for potential improved thermoelectric performance.