Flexible Energy Conversion Research Articles

Eu-viologen based bimetal–organic frameworks nanosheets with Mn atoms anchored on Eu-µ-O skeletons as high-performance negative electrode for flexible asymmetric supercapacitors

Exploring advanced negative electrode materials is imperative to develop high-performance asymmetric supercapacitors for breaking through current energy density limits of supercapacitors, but remains challenging. Herein, a strategy is proposed to create a novel negative electrode by anchoring Mn single-atoms on Eu-viologen metal–organic frameworks (EV-Mn MOFs) nanosheets flowery architectures that self-supported on oxidized carbon cloths (OCC). Such EV-Mn/OCC achieves a negative broadened voltage window (−1 ∼ 0 V) and boosted areal capacitance (840.82 mF cm−2), which is four folds of the isostructural EV/OCC without Mn atoms and surpasses most of currently reported negative electrodes. Also, the EV-Mn/OCC manifests good cycling stability (∼80 % retention for 10,000 cycles). As deduced by the thorough studies of X-ray absorption fine spectra and X-ray photoelectron spectroscopies, the enhanced pseudocapacitance of EV-Mn/OCC definitely correlates to the valence modulation of Mn and Eu through internal electron transfer via Eu-O-Mn bonds on Eu-µ-O skeleton in EV-Mn MOFs. Subsequently, the constructed flexible all-solid-state symmetric supercapacitors employing EV-Mn/OCC as negative electrode can deliver a high energy density (86.89 μWh cm−2) at 1600 μW cm−2, outperforming many asymmetric devices based on traditional negative electrode materials. This work can spur the development of single-atom metallic electronic-modulation strategy for MOFs negative electrode material (MOFs-NEM), and accelerate their applications in flexible energy conversion and storage devices.

Boosting flexible electronics with integration of two‐dimensional materials

AbstractFlexible electronics has emerged as a continuously growing field of study. Two‐dimensional (2D) materials often act as conductors and electrodes in electronic devices, holding significant promise in the design of high‐performance, flexible electronics. Numerous studies have focused on harnessing the potential of these materials for the development of such devices. However, to date, the incorporation of 2D materials in flexible electronics has rarely been summarized or reviewed. Consequently, there is an urgent need to develop comprehensive reviews for rapid updates on this evolving landscape. This review covers progress in complex material architectures based on 2D materials, including interfaces, heterostructures, and 2D/polymer composites. Additionally, it explores flexible and wearable energy storage and conversion, display and touch technologies, and biomedical applications, together with integrated design solutions. Although the pursuit of high‐performance and high‐sensitivity instruments remains a primary objective, the integrated design of flexible electronics with 2D materials also warrants consideration. By combining multiple functionalities into a singular device, augmented by machine learning and algorithms, we can potentially surpass the performance of existing wearable technologies. Finally, we briefly discuss the future trajectory of this burgeoning field. This review discusses the recent advancements in flexible sensors made from 2D materials and their applications in integrated architecture and device design.

Electrospray Deposition for Electronic Thin Films on 3D Freeform Surfaces: From Mechanisms to Applications

AbstractElectronic thin films play a ubiquitous role in microelectronic devices and especially hold great promise for flexible electronics, energy conversion and storage, and biomedical applications. Their characterizations, including ultra‐thin, large‐scale dimensions, stretchability, and conformal ability to curved or 3D structures, present new challenges for thin film fabrication based on the solution method. Electrospray deposition emerges as a feasible method for fabricating large‐area, flexible, and curved films. It offers many advantages such as material adaptability, controlled atomization, tunable film morphology, and shape retention on complex substrates. These advantages make it a key method for fabricating high‐performance films on large‐area, 3D surfaces. This work presents a comprehensive review of the mechanisms, processes, applications, and equipment of electrospray deposition. First, the fundamental principles of electrospray deposition are introduced, focusing on the mechanisms and scaling laws of liquid atomization. Moreover, the control methods for electrospray modes, structures, and film morphology are discussed. These advanced control methods pave the way for the fabrication of smart skins, wearable devices, and energy conversion and storage components. Finally, this work introduces three types of electrospray deposition manufacturing equipment to illustrate the advantages of electrospray deposition for large‐area, and 3D surface manufacturing.

Laser‐Induced Graphene Toward Flexible Energy Harvesting and Storage Electronics

AbstractEnergy harvesting and storage devices play an increasingly important role in the field of flexible electronics. Laser‐induced graphene (LIG) with hierarchical porosity, large specific surface area, high electrical conductivity, and mechanical flexibility is an ideal candidate for fabricating flexible energy devices which supply power for other electronic components. Through a simple laser irradiation process with designable routes, abundant precursors (or substrates) rapidly transform into patterned LIG without any other treatments. The structure and physicochemical properties of LIG can be regulated by controlling the processing strategies and parameters, enabling the optimization of device performance. The laser scribing method, as a non‐contact and in situ technique, proves to be efficient in integrating different LIG‐based devices, resulting in all‐in‐one flexible power platforms. Here, a systematic summary of recent advancements in LIG‐based flexible energy electronics is presented. The controllable synthesis of LIG, functional LIG, and 3D architectures are described by elucidating corresponding mechanisms and processing strategies. An overall review of flexible energy conversion and storage devices based on LIG is presented. Eventually, the challenges and opportunities of LIG‐based materials in flexible energy conversion and storage are briefly discussed.

A comprehensive review on developments and future perspectives of biopolymer‐based materials for energy storage

AbstractDriven by the escalating environmental impact of synthetic materials, there has been a growing focus on employing eco‐sustainable biomass‐derived biopolymers and native materials as a viable alternative to traditional energy storage applications. Biopolymer‐based energy devices, like batteries, supercapacitors, electrode materials, and ion‐exchange membranes, a novel and eco‐conscious approach, hold great potential for flexible and smart electrochemical energy storage and conversion devices, owing to their affordability, environmental sustainability, and biodegradability. This critical review outlines the sources and properties of biopolymers leading to energy storage and emphasizes their utilization in the energy sector. Despite their inherent constraints, biopolymers can be effectively leveraged when combined with other materials in composites. This collaborative approach not only refines their intrinsic physical attributes but also elevates the electrochemical performance of biologically active molecules. In this regard, bionanocomposites, a class of materials combining biopolymers and nanoparticles, have emerged as a promising greener alternative to conventional petroleum‐based polymers. Their biocompatibility, biodegradability, and antimicrobial properties have promoted their increased commercialization, thus paving the way for a more sustainable future. The review concludes by identifying and effectively addressing the limitations, challenges, and future perspectives of biopolymers in energy storage applications.

Hydrogen energy storage integrated grid: A bibliometric analysis for sustainable energy production

Hydrogen energy storage and grid integration are emerging as key technologies for efficient energy generation and decarbonization, addressing the unpredictability of renewable sources like wind and solar. Hydrogen serves as a flexible energy carrier, enabling storage and conversion back to energy, and supporting various applications. Since there is a lack of bibliometric investigation in the grid-connected hydrogen energy storage system, this review conducted the bibliometric analysis and analyzed the role of hydrogen in enhancing grid-connected systems' sustainability and flexibility, based on data from the Scopus database. The principal search terms that have been used to identify the publications are “Hydrogen AND Storage AND ("Grid-connected" OR "On-grid" OR “Grid-tied” OR “Integrated grid” OR “Grid integration”)” and several keywords have also been utilized in the filter including “Hydrogen Storage”, “Hydrogen”, “Hydrogen Production” and “Grid-connected”. The chosen documents type is only comprised of ‘Article’ and ‘Review’. By conducting an analysis of publication trends, citation patterns, co-authorship, and keyword usage, significant and informative observations regarding the development of grid-connected hydrogen storage system research from 2013 to 2023 (up until November) were unveiled. Notably, 86.55% of the articles focused on simulation study, while the rest are focusing in experimental work, reviews, and technical overview of integrated-grid hydrogen storage system. China is establishing itself as prominent participant, while International Journal of Hydrogen Energy is recognized as a notable medium for distributing research on the integrated-grid hydrogen storage system. Compressed hydrogen tank emerges as a prominent type of storage because of its less energy requirement to increase the density of hydrogen that allow more efficient transportation for hydrogen. The review also underlines numerous factors, issues, challenges, and difficulties that next-generation hydrogen energy storage production should overcome with regards to system sustainability.

Decoupled electrolysis for hydrogen production and hydrazine oxidation via high-capacity and stable pre-protonated vanadium hexacyanoferrate

Decoupled electrolysis for hydrogen production with the aid of a redox mediator enables two half-reactions operating at different rates, time, and spaces, which offers great flexibility in operation. Herein, a pre-protonated vanadium hexacyanoferrate (p-VHCF) redox mediator is synthesized. It offers a high reversible specific capacity up to 128 mAh g−1 and long cycling performance of 6000 cycles with capacity retention about 100% at a current density of 10 A g−1 due to the enhanced hydrogen bonding network. By using this mediator, a membrane-free water electrolytic cell is built to achieve decoupled hydrogen and oxygen production. More importantly, a decoupled electrolysis system for hydrogen production and hydrazine oxidation is constructed, which realizes not only separate hydrogen generation but electricity generation through the p-VHCF-N2H4 liquid battery. Therefore, this work enables the flexible energy conversion and storage with hydrogen production driven by solar cell at day-time and electricity output at night-time.

Polar Organic Charge-Transfer Complex of the Asymmetrical Component for Flexible Piezoelectric Energy Harvesting and Self-Powered Wearable Sensors.

Organic piezomaterials have attracted much attention because of their easy processing, lightweight, and mechanic flexibility properties. Developing new smart organic piezomaterials is highly required for new-generation electronic applications. Here, we found a novel organic piezomaterial of organic charge-transfer complex (CTC) consisting of dibenzcarbazole analogue (DBCz) and tetracyanoquinodimethane (TCNQ) in the molecular-level heterojunction stacking mode. The DBCz-TCNQ complex exhibited ferroelectric properties (the saturated polarization of ∼1.23 μC/cm2) at room temperature with a low coercive field. The noncentrosymmetric alignment (Pc space group) led to a spontaneous polarization of this architecture and thus was the origin of the piezoelectric behavior. Lateral piezoelectric nanogenerators (PENGs) based on the thermal evaporated CTC thin-film exhibited significant energy conversion behavior under mechanical agitation with a calculated piezoelectric coefficient (d31) of ∼33 pC/N. Furthermore, such a binary CTC thin-film constructed single-electrode PENG could show steady-state sensing performance to external stimuli as this flexible wearable device precisely detected physiological signals (e.g., finger bending, blink movement, carotid artery, etc.) with a self-powered supply. This work provides that the polar CTCs can act as efficient piezomaterials for flexible energy harvesting, conversion, and wearable sensing devices with a self-powered supply, enabling great potential in healthcare, motion detection, human-machine interfaces, etc.

Anchoring Fe Species on the Highly Curved Surface of S and N Co‐Doped Carbonaceous Nanosprings for Oxygen Electrocatalysis and a Flexible Zinc‐Air Battery

AbstractOxygen reduction reaction (ORR) is of critical significance in the advancement of fuel cells and zinc‐air batteries. The iron‐nitrogen (Fe−Nx) sites exhibited exceptional reactivity towards ORR. However, the task of designing and controlling the local structure of Fe species for high ORR activity and stability remains a challenge. Herein, we have achieved successful immobilization of Fe species onto the highly curved surface of S, N co‐doped carbonaceous nanosprings (denoted as FeNS/Fe3C@CNS). The induction of this twisted configuration within FeNS/Fe3C@CNS arose from the assembly of chiral templates. For electrocatalytic ORR tests, FeNS/Fe3C@CNS exhibits a half‐wave potential (E1/2) of 0.91 V in alkaline medium and a E1/2 of 0.78 V in acidic medium. The Fe single atoms and Fe3C nanoparticles are coexistent and play as active centers within FeNS/Fe3C@CNS. The highly curved surface, coupled with S substitution in the coordination layer, served to reduce the energy barrier for ORR, thereby enhancing the intrinsic catalytic activity of the Fe single‐atom sites. We also assembled a wearable flexible Zn‐air battery using FeNS/Fe3C@CNS as electrocatalysts. This work provides new insights into the construction of highly curved surfaces within carbon materials, offering high electrocatalytic efficacy and remarkable performance for flexible energy conversion devices.

Anchoring Fe Species on the Highly Curved Surface of S and N Co-Doped Carbonaceous Nanosprings for Oxygen Electrocatalysis and a Flexible Zinc-Air Battery.

Oxygen reduction reaction (ORR) is of critical significance in the advancement of fuel cells and zinc-air batteries. The iron-nitrogen (Fe-Nx ) sites exhibited exceptional reactivity towards ORR. However, the task of designing and controlling the local structure of Fe species for high ORR activity and stability remains a challenge. Herein, we have achieved successful immobilization of Fe species onto the highly curved surface of S, N co-doped carbonaceous nanosprings (denoted as FeNS/Fe3 C@CNS). The induction of this twisted configuration within FeNS/Fe3 C@CNS arose from the assembly of chiral templates. For electrocatalytic ORR tests, FeNS/Fe3 C@CNS exhibits a half-wave potential (E1/2 ) of 0.91 V in alkaline medium and a E1/2 of 0.78 V in acidic medium. The Fe single atoms and Fe3 C nanoparticles are coexistent and play as active centers within FeNS/Fe3 C@CNS. The highly curved surface, coupled with S substitution in the coordination layer, served to reduce the energy barrier for ORR, thereby enhancing the intrinsic catalytic activity of the Fe single-atom sites. We also assembled a wearable flexible Zn-air battery using FeNS/Fe3 C@CNS as electrocatalysts. This work provides new insights into the construction of highly curved surfaces within carbon materials, offering high electrocatalytic efficacy and remarkable performance for flexible energy conversion devices.

Two-dimensional Be2P4 as a promising thermoelectric material and anode for Na/K-ion batteries.

Incredibly effective and flexible energy conversion and storage systems hold great promise for portable self-powered electronic devices. Owing to their large surface area, exceptional atomic structures, superior electrical conductivity and good mechanical flexibility, two-dimensional (2D) materials are recognized as an attractive option for energy conversion and storage application. In this work, we examined the stability, electronic, thermoelectric and electrochemical aspects of a novel 2D Be2P4 monolayer by adopting density functional theory (DFT). The Be2P4 monolayer exhibits a direct semiconductor gap of 0.9 eV (HSE06), large Young's modulus (∼198 GPa), high carrier mobility (∼104 cm2 V-1 s-1) and a low excitonic binding energy of 0.11 eV. Our calculated findings suggest that Be2P4 shows a lattice thermal conductivity of 1.02 W m K-1 at 700 K, resulting in moderate thermoelectric performance (ZT ∼ 0.7), encouraging its use in thermoelectric materials. In addition, a higher adsorption energy of -2.28 eV (-2.52 eV) and less diffusion barrier of 0.22 eV (0.17 eV) for Na(K)-ion batteries promote fast ion transport in the Be2P4 monolayer. This material also shows a high specific capacity and superior energy density of 8460 W h kg-1 (8883 W h kg-1) for Na(K)-ion batteries. Thus, our results offer insightful information for investigating potential thermoelectric and flexible anode materials based on the Be2P4 monolayer.

Nanosheet Zinc Oxide Synthesized by Solution-Immersion Method for Triboelectric Nanogenerator

Most global problems are being solved by using sustainable energy harvesting technologies to retain the social ecosystem in great condition. The triboelectric nanogenerator (TENG) which is a renewable energy harvesting device, collects the waste mechanical energy from its surroundings and performs the electric signal conversion. TENG have garnered increased attention in recent years by offering prospective use in energy harvesting technology. Particularly, there is a need for flexible energy conversion that serves as a power supply for portable electronic equipment. In this study, ZnO nanosheet thin film prepared on the flexible conductive aluminium foil through a low temperature immersion technique was used to generate electrical energy. The effect of heat treatment on ZnO nanosheet thin film was also investigated on the surface morphology, strutural properties and nanogerator performance. The high density of interconnected ZnO nanosheet were observed before and after heat treatment as confirmed by FESEM studies. The analysis using XRD confirmed that ZnO nanosheet thin film was successfully deposited on the aluminium foil. Additionally, the ZnO nanosheet thin films improved significantly with heat treatment, enhancing their crystalline quality. The triboelectric nanogenerator (TENG) was successfully constructed in contact and separation mode using Kapton tape on top and ZnO nanosheet thin film on the bottom to generate electricity by a force of hand pressing. The output electrical voltage of the device doubled from around 2 V to 4 V after underwent the heat treatment. This study provides an essential insight into fabrication of TENG using the ZnO nanosheet thin film through a clean and effective method for nanogenerator applications.

Multi-stage and multi-timescale optimal energy management for hydrogen-based integrated energy systems

With the technological advances of flexible multiple energy conversion and utilization, hydrogen energy has attracted increasing attention. The hydrogen-based integrated energy system (HIES) consisting of multiple microgrids (MGs) with hydrogen exchanges among MGs is considered a promising hydrogen utilization paradigm. To facilitate the coordination among multiple MGs, this paper proposed a multi-stage and multi-timescale energy management for a HIES considering the electricity-heat-hydrogen supply-demand balance and demand uncertainties. The proposed solution consists of three stages, i.e. the day-ahead scheduling stage, model predictive control (MPC) based intraday rolling dispatch stage and intraday real-time adjustment stage to participate in the electricity and hydrogen market. In the HIES, hydrogen energy can be dispatched and utilized across MGs to enable flexible energy management and improve energy utilization efficiency. The proposed solution is extensively assessed through the IEEE 33-bus test network with a HIES compared with three benchmark solutions and the numerical results confirm its effectiveness and economic benefits.

Dry Methane Reforming in a Piston Engine for Chemical Energy Storage and Carbon Dioxide Utilization: Kinetic Modeling and Thermodynamic Evaluation

The flexible energy conversion in piston engines offers one possibility for storing energy from renewable sources. This work theoretically explores the engine‐based dry methane reforming converting mechanical energy into chemical energy. The endothermic, endergonic reforming process is activated by the temperature increase during the compression stroke, assisted by a reduction of the heat capacity through dilution with argon. This leads to an increase in chemical exergy, as higher‐exergy species are produced with small exergy losses while simultaneously consuming CO2. The engine‐based homogenous dry reforming serves as a flexible power‐to‐gas process and energy storage solution, presenting an alternative to catalytic processes. The piston engine is simulated using a time‐dependent single‐zone model with detailed chemical kinetics, followed by an analysis of thermodynamics and kinetics. With inlet temperatures ranging from 423–473 K and argon dilutions of 91–94 mol%, CH4 and CO2 conversion are between 50%–90% and 30%–80%, respectively, resulting in synthesis gas yields of 45–55%. Additionally, higher hydrocarbons such as C2H2, C2H4, and C6H6 are produced with yields of up to 20%, 10%, and 10%. So, this power‐to‐gas process allows for exergy storage of up to 3.35 kW L−1 per cycle with an efficiency of up to 75%.

Oxygen functionalization‐assisted anionic exchange toward unique construction of flower‐like transition metal chalcogenide embedded carbon fabric for ultra‐long life flexible energy storage and conversion

AbstractThe metal‐organic framework (MOF) derived Ni–Co–C–N composite alloys (NiCCZ) were “embedded” inside the carbon cloth (CC) strands as opposed to the popular idea of growing them upward to realize ultrastable energy storage and conversion application. The NiCCZ was then oxygen functionalized, facilitating the next step of stoichiometric sulfur anion diffusion during hydrothermal sulfurization, generating a flower‐like metal hydroxysulfide structure (NiCCZOS) with strong partial implantation inside CC. Thus obtained NiCCZOS shows an excellent capacity when tested as a supercapacitor electrode in a three‐electrode configuration. Moreover, when paired with the biomass‐derived nitrogen‐rich activated carbon, the asymmetric supercapacitor device shows almost 100% capacity retention even after 45,000 charge–discharge cycles with remarkable energy density (59.4 Wh kg–1/263.8 µWh cm–2) owing to a uniquely designed cathode. Furthermore, the same electrode performed as an excellent bifunctional water‐splitting electrocatalyst with an overpotential of 271 mV for oxygen evolution reaction (OER) and 168.4 mV for hydrogen evolution reaction (HER) at 10 mA cm−2 current density along with 30 h of unhinged chronopotentiometric stability performance for both HER and OER. Hence, a unique metal chalcogenide composite electrode/substrate configuration has been proposed as a highly stable electrode material for flexible energy storage and conversion applications.

In-Situ Formation of NiFe-MOF on Nickel Foam as a Self-Supporting Electrode for Flexible Electrochemical Sensing and Energy Conversion

Ni- and Fe-based metal-organic frameworks (NiFe-MOFs) have abundant valence states and have the potential to be used as bifunctional electrode materials. However, unannealed NiFe-MOFs are still not widely used in electrode materials, including electrochemical sensing, supercapacitors, and overall water splitting. In addition, the direct growth of active material on a conductive carrier has been developed as a binder-free strategy for electrode preparation. This strategy avoids the use of insulating binders and additional electrode treatments, simplifies the preparation process of the NiFe-MOFs, and improves the conductivity and mechanical stability of the electrode. Therefore, in this study, we employed a simple solvothermal method combined with an in situ growth technique to directly grow NiFe-MOF-X (X = 4, 8, 12) nanomaterials of different sizes and morphologies on nickel foam at low reaction temperatures and different reaction times. The NiFe-MOF-8 electrode exhibited high capacitive properties, with an area-specific capacitance of 5964 mF cm−2 at 2 mA cm−2 and excellent durability. On the other hand, NiFe-MOF-12 exhibited strong catalytic activity in electrocatalytic tests performed in a 1 M KOH aqueous solution, demonstrating hydrogen evolution reaction (η10 = 150 mV) and oxygen evolution reaction (η50 = 362 mV) activities. The electrochemical sensing tests demonstrated a good response to BPA. Overall, our results suggest that the direct growth of NiFe-MOFs on nickel foam using a simple solvothermal method combined with an in situ growth technique is a promising strategy.

Theoretical design and discovery of two‐dimensional materials for next‐generation flexible piezotronics and energy conversion

AbstractTwo‐dimensional (2D) materials are at the epicenter of the current nanotechnology research for its intriguing properties. It has the advantage of high flexibility, high surface to volume ratio, robust mechanical strength and are stackable in contrary to bulk materials. Piezoelectric effect is exploited in 2D layered nanomaterials with broken inversion symmetry and non‐zero band gap for applications in energy harvesting and energy conversion. Density functional theory (DFT) is a powerful tool to predict the piezoelectric properties of 2D materials. This mini review emphasizes the importance and discusses the challenges of different methods within DFT‐based framework to compute piezoelectric properties. Recent simulation works of piezoelectric engineering in novel 2D semiconductors for in‐plane and out‐of‐plane piezoelectricity are reviewed. Various controlling parameters and techniques for piezoelectric effect are also discussed. Theoretical predictions pave the path for experimental exploration of 2D materials exhibiting strong piezoelectric properties and to replace the commercially used lead‐based toxic materials in future devices.

Rapid dissolution of chitin and chitosan with degree of deacetylation less than 80% in KOH/urea aqueous solution

The rapid dissolution of chitin and chitosan with degree of deacetylation less than 80% in the universal solvent KOH/urea aqueous solution were comprehensively investigated. A desolvation–intercalation dissolution mechanism was proposed.

Surrogate model assisted multi-criteria operation evaluation of community integrated energy systems

Operational evaluation is critical for revealing the operational performance and improvement potential of community integrated energy systems (CIESs). However, complex system configuration and flexible energy conversion in a CIES render the evaluation more challenging. Both the loss in energy quality and quantity should be considered to comprehensively evaluate the energy utilization capability of a CIES. Accurately quantified evaluation requires the optimal solution as the reference, which incurs a heavy computational burden and limits its applicability under massive scenarios. This paper proposes a surrogate model assisted quantified evaluation method for CIES operation considering the variation in energy quality and to show the gap to optimal performance. First, exergy theory is adopted to analyze the matching degree between the input and output energy quality. Second, three indicators are considered as examples to reveal the operational performance in terms of system efficiency, renewable energy penetration, and operation cost. The scores of quantified evaluation are derived using the technique for order preference by similarity to an ideal solution (TOPSIS) method. Third, a CNN-based surrogate model is designed to replace the time-consuming optimization problems for the optimal reference solution, which effectively accelerates the evaluation efficiency under massive scenarios. Case studies demonstrate the effectiveness of the evaluation methods and efficiency of the proposed surrogate model.

Numerical analysis and two-phase modeling of water Graphene Oxide nanofluid flow in the riser condensing tubes of the solar collector heat exchanger

Graphene Oxide is one of the carbon-based-materials that has wide application range such as Water purification, Flexible rechargeable battery electrode, Solar Collectors, and Energy conversion. In this research, initially, Graphene Oxide nanoparticles were dispersed in water to make a nanofluid. The nanofluid was prepared at 0.10, 0.15, 0.20, 0.25, 0.35, and 0.45% mass fractions. After that, heat transfer and viscosity (at 10 and 100 Revolutions per minute (RPM)) of the prepared samples were calculated at 25, 30, 35, 40, 45, and 50 °C temperatures. In the Flat Plate Solar Collector (FPSC) - Riser tube, from the start point to the end of tube, the temperature decreases and thus the heat transfer and viscosity change. As the calculated range does not contain all the temperatures and mass fractions, and to lower the experimental costs, thus, Fuzzy system and Artificial Neural Network models were used to predict the whole range of data. After that, the trained models were compared to detect the error and to choose the best model with the least error. Results confirmed that Fuzzy system has lower error. This means that Fuzzy system predicts the input-target dataset as definite as obtainable.