High Energy Storage Efficiency Research Articles

Ni-modified BaTiO3 film prepared by sol-gel with high energy storage performance

The development of lead-free dielectric capacitors with high recoverable energy storage density and high energy storage efficiency is important for improving the overall performance of electronic and power systems. BaTiO3 (BTO) is one of the most common ferroelectric materials and has attracted much attention for energy storage applications in the past decades due to its excellent dielectric and ferroelectric properties. However, high remnant polarization and low electrical breakdown strength of BTO limit its development in energy storage applications. Many efforts (e.g., elements doping, interface/heterostructure, etc.) have been made to improve the energy storage density of BTO thin films. In this paper, Ba1-xNixTiO3 thin films (x = 0, 0.02, 0.04, 0.06, 0.08; abbreviated as BNxT) were synthesized via sol-gel and spin-coated method. The effect of Ni doping on the structural, dielectric, ferroelectric and energy storage properties of BTO thin films has been studied. The results confirmed that with the increase of Ni doping, a second phase arises and the dielectric constant decreases. While appropriate Ni doping led to the improvement of the breakdown strength, further increase of Ni deteriorated the energy storage because of the high oxygen vacancy. Finally, optimized energy storage performance was obtained for BN0.04T thin film: dielectric constant of 401, dielectric loss of 0.002, recoverable energy density of 20.2 J/cm3 and energy storage efficiency of 83.6% at 965 kV/cm. Meanwhile, the remnant and maximum polarization of the films were 0.06 μC/cm2 and 50 μC/cm2, respectively. BN0.04T thin film has an excellent application prospect and is expected to appear as a component in the future composite energy storage film system.

Significantly improve capacitive properties of alicyclic polyimide dielectrics at high temperatures via hard/soft segment engineering

The demand for high energy storage density and efficiency of polymer film capacitors at high temperatures is urgently increasing in the electronics and electrical field. However, most traditional high temperature resistant polymers exhibit the low bandgap and high conductive loss because of the presence of conjugated aromatic structures, resulting in a significant decrease in the energy storage performance at high temperatures and high fields. In this paper, a series of alicyclic polyimide dielectric films containing hard segment of phenyl imide and soft segment of cyclohexyl imide are designed and prepared. On the one hand, the introduction of non-coplanar alicyclic ring into main-chain of polyimide can break long distance conjugation effect, weaken the intermolecular and intramolecular charge transfer interaction and improve the bandgap. On the other hand, the physical crossing point formed by the soft segments can sharply increase Young's modulus of the polyimide films. As a result, the terpolymer polyimide film (CPI90) with copolymerization ratio of phenyl/cyclohexyl dianhydride of 9:1 achieves a highest discharge energy density (Ud) of 5.59 J cm−3 at 150 °C. Importantly, the CPI90 film can obtain the Ud of 2.74 J cm−3 at 200 °C. In addition, the CPI90 film possesses a good self-healing ability attributing to a small ratio for the carbon to hydrogen and oxygen. This work offers a new strategy for synergistically promoting the bandgap and Young's modulus of polymer dielectrics via molecular and hard/soft segment engineering.

Aliovalent doping engineering to synergistically optimize the energy storage properties of Sr0.7Bi0.2TiO3-based linear-like relaxor ferroelectric ceramics

Dielectric capacitors with high energy storage density and power density are essential for the miniaturization and lightweight design of electronic devices. However, current applications are hampered by the challenge of simultaneously achieving high recoverable energy storage density and efficiency, as well as the fact that many dielectric energy storage ceramics contain lead elements. In this study, a multiple optimization strategy is proposed to significantly increase the breakdown strength while maintaining a high polarization strength by forming Bi3+-Li+ defect pairs to disrupt the paraelectric phase, and by introducing aliovalent double ions Li+ and La3+ to increase the cationic disorder. The change of domain structure and the relaxation enhancement mechanism is analyzed by dielectric properties and first-order reversal curve. Band gap, impedance and numerical simulations reveal the breakdown strength enhancement mechanism. As a result, the ceramics achieve a remarkable combination of high Wrec of 4.4 J/cm3 and high ƞ of 90 % at 420 kV/cm. Furthermore, the ceramic exhibits exceptional stability and fatigue resistance. Notably, the ceramic obtains a power density of 99.5 MW/cm3 and a rapid discharge rate of 0.22 µs. These findings demonstrate the excellent potential of Sr0.7Bi0.2TiO3-based ceramics as an alternative to Pb-based ceramics, and provide an effective strategy for developing advanced energy storage materials.

PbZrO3-based thin film capacitors with high energy storage efficiency

Antiferroelectric (Pb0.87Sr0.05Ba0.05La0.02)(Zr0.52Sn0.40Ti0.08)O3 thin film capacitors were fabricated for dielectric energy storage. Thin films with excellent crystal quality (FWHM 0.021°) were prepared on (100) SrRuO3/SrTiO3 substrates by pulsed laser deposition. The out-of-plane lattice constant of the thin film was 4.110 ± 0.001 Å. An average maximum recoverable energy storage density, 88 ± 17 J cm−3 with an efficiency of 85% ± 6% at 1 kHz and 80 ± 15 J cm−3 with an efficiency of 91% ± 4% at 10 kHz, was achieved at room temperature. The capacitor was fatigue resistant up to 106 cycles at an applied electric field of 2 MV cm−1. These properties are linked to a low level of hysteresis and slow polarization saturation. PbZrO3-derived oxide thin film capacitors are promising for high efficiency and low loss dielectric energy storage applications.

Simultaneous achievement of high energy storage density and ultrahigh efficiency in BCZT-based relaxor ceramics at moderate electric field

The development of high-performance energy storage dielectric materials is the key to the development of large capacity ceramic capacitor. How to obtain the high energy storage density and efficiency of dielectric materials is the basis. Ba0.85Ca0.15Zr0.1Ti0.9O3 (BCZT) has high energy storage potential as a typical piezoelectric material, but it shows poor energy storage properties due to low breakdown electric field and large remnant polarization. In this work, we propose a combined optimization strategy aimed at enhancing the comprehensive energy storage performance of BCZT-based ceramics through doping with bismuth-based oxides. The diverse phase morphology offers substantial potential for modifying the electrical properties of BCZT-based ceramics. Electrical homogeneity is markedly improved with the incorporation of Bi2/3(Al1/2Nb1/2)O3 (BAN), which is accompanied by a reduction in long-range ferroelectric phases and the emergence of polar nanoregions. Ultimately, optimal BCZT-xBAN ceramics with x = 0.09 exhibit superior energy storage performances (Wrec ∼ 3.71 J/cm3, η ∼ 94.54 %) under moderate electric fields. Furthermore, BCZT-0.09BAN ceramics demonstrate commendable fatigue endurance, frequency stability, and temperature stability characteristics; notably achieving an ultrafast discharge rate of t0.9–14.6 ns alongside excellent discharge properties (CD ∼ 1278.66 A/cm2, PD ∼ 191.80 MW/cm3, WD ∼ 1.57 J/cm3).

Double enhancement of energy storage density in relaxor ferroelectric 0.8BaTiO3-0.2BiScO3 by Li defect-regulated strategy

To meet the ever-increasing demands for pulsed power technologies, the development of lead-free dielectric ceramics with a large energy storage density (Wrec) and high energy storage efficiency (η) is crucial for enhancing the electrical performance of power capacitive devices. The conventional solid-solution, while effective in suppressing long-range order and improving energy storage performances, often results in a reduction of maximum polarization. This reduction necessitates the application of a larger electric field to obtain a relatively high Wrec. Herein, an effective strategy to enhance Wrec again via inducing Li-related defect dipoles is proposed. By introducing (Bi0.5Li0.5)TiO3 into 0.8BaTiO3-0.2BiScO3 matrix, the polarization contribution from defect dipoles together with intrinsic polarization induces an at least two-time enhancement in Pmax. Our findings indicate ∼62.9 % enhancement in the Wrec of 0.8BT-0.2BS, elevating from 2.56 J cm−3 to 4.17 J cm−3 at electrical field of 300 kV cm−1, while preserving an energy storage efficiency of 90.35 %. Furthermore, it also exhibits good thermal stability with the variations of ΔWrec < 3 % and η< 5 %. This research introduces a novel strategy for defect regulation strategy in the design of high-performance dielectric materials, which is expected to expedite the optimization of the advanced energy storage capacitors.

Ultra-high energy storage efficiency achieved through the construction of interlocking microstructure and excitation of depressor effects

Glass-ceramic capacitors struggle to balance high energy storage efficiency (η>90 %) and sufficient breakdown field strength (Eb), hindering their use in energy storage. Interface polarization, caused by the accumulation of free charge, reduces breakdown strength. We prepared glass-ceramic materials with varying contents of the glass phase using traditional melting techniques, adjusting the glass content to enhance an interlocking structure between the glass and crystal phases, reducing Interface polarization. Divalent metal oxide BaO in the glass stimulated a depressor effect, filling gaps and increasing resistivity. The optimal composition (x = 0.2) achieved a 95 % energy storage efficiency and an energy storage density of 4.4 J/cm3 at 680 kV/cm, while x = 0.25 reached an ultra-high energy storage efficiency of 99 %. Increasing glass content reduced activation energy for Interface polarization (Ei) from 1.27 eV to 1.08 eV. Samples with x = 0.2 exhibited low dielectric loss (∼0.005), high dielectric constant (∼142), ultra-high power density (∼52.8 MW/cm3), and ultra-fast discharge speed (∼26 ns), suggesting future potential for high-performance glass-ceramic materials.

A novel kapok fiber aerogel based phase change materials with high thermal conductivity and efficient energy storage for photovoltaic thermal management

In response to the evolving energy crisis and environmental changes, solar photovoltaic systems are progressively emerging as common substitutes to fossil fuels. However, the substantial heat accumulation on the surface of photovoltaic panels significantly impacts their photoelectric performance. Consequently, effective thermal management solutions are essential to address these key issues. In this study, a novel composite phase change material (TD@CKF-PVA) was designed. It utilizes a three-dimensional network structure constructed from cross-linked polyvinyl alcohol (PVA) and kapok fiber (KF) as the scaffold, and 1-tetradecanol (TD) as the phase change material. This composite material exhibits excellent thermal conductivity of 0.93 W/mK and efficient thermal energy storage capacity of 204 J/g. The coating of carbon nanotubes on KF provides additional thermal pathways, significantly enhancing the thermal conductivity of the phase change composite material. TD@CKF-PVA phase change materials also demonstrate outstanding thermal management capabilities in both time and space dimensions, effectively reducing the heat accumulation on solar photovoltaic panels and improving their output power and photoelectric efficiency. This work not only showcases the great potential of TD@CKF-PVA for thermal energy management but also provides an efficient approach to dissipating heat from PV panels.

High energy storage efficiency in lead-free perovskite (1-x)(0.3Ba0.85Ca0.15Zr0.1Ti0.9O3-0.7SrTiO3)-xBiMg1/2Ti1/2O3 ceramics with superparaelectric design

High energy storage efficiency in lead-free perovskite (1-x)(0.3Ba0.85Ca0.15Zr0.1Ti0.9O3-0.7SrTiO3)-xBiMg1/2Ti1/2O3 ceramics with superparaelectric design

Enhanced high-temperature energy storage performance in all-organic dielectric films through synergistic crosslinking of chemical and physical interaction

Advanced electronic devices and energy systems urgently require high-temperature polymer dielectrics that can offer both high discharge energy density and energy storage efficiency. However, the capacitive properties of most polymers sharply deteriorate at elevated temperatures, due to the significant rise in leakage current density and energy loss. Herein, a new design approach is adopted to fabricate high-temperature polyetherimide (PEI) dielectrics with chemical and physical cooperative crosslinking networks, the dual-crosslinked PEI dielectrics are prepared through amine crosslinking agent and the electrostatic interaction of oppositely charged phenyl groups between triptycene (TE) and PEI chain segments. Benefiting from the increased crosslinking sites, the dual-crosslinked PEI films achieve the simultaneously enhancement in Tg, modulus and bandgap compared to un-crosslinked and single-crosslinked polymers. Meanwhile, the PEI with dual-crosslinked network displays higher chain packing density, effectively reducing the mean motion pathways of charge carriers and the conduction loss inside polymer dielectric. Consequently, the dual-crosslinked PEI containing 0.25 wt% TE delivers an outstanding discharge energy density of 2.69 J/cm3 and retains excellent cyclability after 100,000 charge–discharge cycles at 200 ℃. Additionally, finite element analysis and molecular dynamics simulation further confirm that less Joule heat and tighter chain structure are formed in the dual-crosslinked polymer dielectric. This research offers a novel methodology to prepare high-performance polymer dielectrics for high-temperature applications.

Boosting K+-Ionic Conductivity of Layered Oxides via Regulating P2/P3 Heterogeneity and Reciprocity for Room-Temperature Quasi-Solid-State Potassium Metal Batteries.

Solid-state potassium metal batteries are promising candidates for grid-scale energy storage due to their low cost, high energy density and inherent safety. However, solid state K-ion conductors struggle with poor ionic conductivity due to the large ionic radius of K+-ions. Herein, we report precise regulation of phase heterogeneity and reciprocity of the P2/P3-symbiosis K0.62Mg0.54Sb0.46O2 solid electrolyte (SE) for boosting a high ionic conductivity of 1.6×10-4 S cm-1 at 25 °C. The bulk ionic conducting mechanism is explored by elucidating the effect of atomic stacking mode within the layered framework on K+-ion migration barriers. For ion diffusion at grain boundaries, the P2/P3 biphasic symbiosis property assists in tunning the SE microstructure, which crystallizes in rod-like particles with lengths of tens of micrometers facilitating long-distance ion transport and significantly decreasing grain boundary resistance. Potassium metal symmetric cells using the modified SE deliver excellent cycling life over 300 h at 0.1 mA cm-2 and a high critical current density of 0.68 mA cm-2. The quasi-solid-state potassium metal batteries (QSSKBs) coupled with two kinds of layered oxide cathodes demonstrate remarkable stability over 300 cycles, outperforming the liquid electrolyte counterparts. The QSSKB system provides a promising strategy for high-efficiency, safe, and durable large-scale energy storage.

Enhanced energy storage performance in NBT-based MLCCs via cooperative optimization of polarization and grain alignment

Dielectric ceramics possess a unique competitive advantage in electronic systems due to their high-power density and excellent reliability. Na1/2Bi1/2TiO3-based ceramics, one type of extensively studied energy storage dielectric, however, often experience A-site element volatilization and Ti4+ reduction during high-temperature sintering. These issues may result in increased energy loss, reduced polarization and low dielectric breakdown electric field, ultimately making it challenging to achieve both high energy storage density and efficiency. To address these issues, we introduce a synergistic optimization strategy that combine polarization engineering and grain alignment engineering. First principles calculations and experimental analyses show that the doping of Mn2+ can suppress the reduction of Ti4+ in Na1/2Bi1/2TiO3-based ceramics and enhance ion off-centering displacements, thereby reducing energy loss and improving polarization. In addition, we prepared multilayer ceramic capacitors with grains oriented along the <111> direction using the template grain growth method. This approach effectively reduces electric-field-induced strain by 37% and markedly enhances breakdown electric field by 42% when compared with nontextured counterpart. As a result of this comprehensive strategy, <111 >-textured Na1/2Bi1/2TiO3-based multilayer ceramic capacitors achieve an ultra-high energy density of 15.7 J·cm−3 and an excellent efficiency beyond 95% at 850 kV·cm−1, exhibiting a superior overall energy storage performance.

Superior energy storage performance in NaNbO3‐based lead‐free ceramics under low electric field

AbstractNaNbO3 (NN)‐based materials have attracted widespread attention due to their advanced energy storage performance and eco‐friendliness. However, achieving high recoverable energy storage densities (Wrec) and efficiency (η) typically requires ultrahigh electric fields (E &gt; 300 kV/cm), which can limit practical use. In this work, we present a synergistic strategy that employs the ferroelectric material Bi0.5Na0.5TiO3 (BNT) to augment the Pmax and the linear material Bi0.2Sr0.7TiO3 (BST) to optimize the P–E loops. Furthermore, a two‐step sintering process is implemented to preserve high Pmax values under lower electric field. As a result, ternary (1−x)(0.90NN‐0.10BNT)‐xBST was successfully prepared, achieving a high Wrec of 5.1 J/cm3 and a η of 85% in x = 0.20 samples at a low electric field of 290 kV/cm. Moreover, the x = 0.20 samples showed good frequency stability (1–200 Hz) and temperature stability (27°C–100°C). These results provide guidance for the development of ceramics with high energy storage properties under low electric fields.

Organic Dye Molecule Intercalated Prussian Blue for Simultaneously Enhancing Coloration Efficiency and Energy Storage Capacity in Electrochromic Battery.

The dual-functional device combining electrochromic properties and energy storage has gained numerous attentions in the field of energy-saving smart electronics. However, achieving simultaneous optimization of coloration efficiency and energy storage capacity of materials poses a significant challenge. This study presents a novel approach by incorporating methyl orange into Prussian blue channels (PB-MO films) to adjust the internal electronic structure of Prussian blue. This modification allows the active layer to simultaneously improve the electrochromic and energy storage performance. The introduction of methyl orange not only alters the ratio of Fe3+/Fe2+ within the framework through the coordination reaction of Fe3+ with methyl orange, but also improves the reaction kinetics after intercalating organic dye molecules, including charge transfer resistance, diffusion capability of ions and capacitive contribution. The PB-MO films demonstrate remarkable properties: high optical contrast (81.4% at 670nm), excellent coloration efficiency (265 cm2C-1), and significant specific capacity (84 mAh m-2 at 0.05 A m-2), outperforming pure PB films. The PB-MO films are ideally suited for applications in displays and intelligent energy storage fields, boasting both high coloration efficiency and substantial energy storage capacity, thus advancing promote the development of dual-functional electrochromic devices.

A Recyclable Energy Storage Wood Composite with Photothermal Conversion Properties for Regulating Building Temperature

AbstractAddressing the challenges of energy storage liquid leakage and long‐term stability in energy storage is crucial for achieving sustainable energy efficiency. In this study, polymethyl methacrylate (PMMA) is innovatively employed as an encapsulation film on the surface of the wood‐based phase change material, resulting in a recyclable wood‐based composite energy storage material (PPW). A novel energy storage liquid (PCMs) composed of lauric acid (LA), capric acid (CA), and polyethylene glycol (PEG) is immersed in the pretreated porous wood frame through vacuum impregnation. The PCMs imparted a phase change temperature of 21.0 °C, which is close to human comfort levels, and a high energy storage efficiency of 31.6 J g−1 to the PPW. Additionally, the PCMs provided the PPW with a photothermal conversion efficiency of 29.3%. Even after 200 freeze‐thaw cycles, the energy storage properties of the PPW remained nearly unchanged. Therefore, utilizing PMMA as an effective encapsulation material is a viable approach to prevent leakage of the phase change solution and enhance the recyclability of the PPW. Furthermore, the transparency of PMMA preserves the natural appearance of the wood, thereby broadening the application potential of PPW in residential buildings, thermal energy storage, and solar thermal conversion systems.

High energy storage performance in SrZrO3-modified quaternary relaxor ferroelectric ceramics

Lead-free relaxor ferroelectric ceramics have attracted much attention in pulse power systems owing to their excellent energy storage performance and environmentally friendly characteristics. However, it is challenging to simultaneously achieve high energy storage density and efficiency in ferroelectric ceramics for practical applications. Herein, a novel optimization strategy is designed by introducing a linear dielectric SrZrO3 (SZ) with wide bandgap (Eg) into the BaTiO3-Bi0.5Na0.5TiO3-NaNbO3 (BT-BNT-NN) to form quaternary ceramics, disrupting long-range ferroelectric ordering and constructing weakly coupled polar nanoregions (PNRs). As a result, the recoverable energy density (Wrec) and energy storage efficiency (η) are simultaneously improved in (1-x) (BT-BNT-NN)-xSZ ceramics. At an electric field of 530 kV/cm, a Wrec of 3.37 J/cm3 and an η of 82.5 % were optimally achieved at x = 0.16 due to the formation of slim P-E loops, delayed polarization saturation, and ultra-high breakdown field strength (Eb), where the improvement of Eb is attributed to the reduction of porosity and the increase of Eg. Furthermore, the as-fabricated samples also exhibit excellent frequency and temperature stability. This study provides an effective method for developing high-performance dielectric capacitors for energy storage applications.

Enhanced energy storage properties of BaTiO3 ceramics: Effect of doping Bi(Mg0.25Zn0.25Ti0.5)O3 on microstructure, dielectric and ferroelectric properties

(1-x) BaTiO3 – x Bi(Mg0.25Zn0.25Ti0.5)O3 (x = 0.00, 0.06, 0.12, 0.20,molar ratio) ceramics were prepared by solid sintering method. The effects of Bi(Mg0.25Zn0.25Ti0.5)O3 (BMZT) doping on microstructure, dielectric, ferroelectric and energy storage properties of BaTiO3 (BTO) were studied. With BMZT addition, the sintering temperature gradually decreases, the grain size reaches a minimum at x = 0.12 and the phase structure changes from tetragonal to cubic. And dielectric properties changed from temperature-dependent to temperature-insensitive. Additionally, higher cubic phase content induced slim polarization and electric field (P-E) loop and low remnant polarization (Pr). Therefore, 0.88 BaTiO3 - 0.12 Bi(Mg0.25Zn0.25Ti0.5)O3 ceramics achieved recoverable energy storage density (Wrec) of 702.7 mJ/cm3 and high energy efficiency of 87.3 % under electric field of 93 kV/cm. It exhibited optimum properties, including a minimum grain size (0.620 μm), superior dielectric properties (εr = 1811.3, tanδ = 0.0552 at 1150 °C), a high maximum polarization strength (14.3 μC/cm2), and the maximum dielectric breakdown strength (93 kV/cm), as identified in the present study. It simultaneously maintains high energy storage density and efficiency over a wide electric field range and large temperature range (room temperature - 90 °C). Thus (1-x) BaTiO3 – x Bi(Mg0.25Zn0.25Ti0.5)O3 ceramics are a promising material for energy storage applications.

High-performance electric energy storage in BiFeO3–Ba(Ti0.8Zr0.2)O3 relaxor ferroelectric ceramics

Perovskite relaxor ferroelectrics have been widely developed for energy storage applications due to their exceptional dielectric properties. This work explores the energy storage performance, thermal stability, and structural evolution in (1-x)BiFeO3–x Ba(Ti0.8Zr0.2)O3 ceramics (x = 0.3, 0.4, 0.5, and 0.6) via modulating Ba(Ti0.8Zr0.2)O3 (BZT) concentration. An enhancement of breakdown electric field from 120 kV/cm at x = 0.3–220 kV/cm at x = 0.5 can be attributed to increased grain boundaries and nanodomains as electric barriers to inhibit charge mobility. A high recoverable energy density of 5.9 J/cm3 and a high energy efficiency of 86.2 % were achieved at x = 0.5 and 0.6, respectively. The structure shifts from ferroelectric rhombohedral R3c symmetry toward a coexistence of nonpolar symmetries (including tetragonal P4/mmm, cubic Pm-3m, and orthorhombic Pbnm) with increasing BZT. The integration of BZT in BiFeO3 demonstrates to break the long-range order and promote the formation of polar nanoregions and nanodomains, leading to a high-efficiency energy storage.

Constructing hollow cobalt sulfide nanocages strung by manganese molybdate nanorods for high-efficiency supercapacitors and electrocatalytic methanol oxidation

Constructing core-shell heterostuctures with rationally designed nanoarchitectures and components is a promising strategy to pursuit high-efficiency energy storage and conversion in supercapacitors (SCs) and direct methanol fuel cells (DMFCs). Herein, a multi-dimensional MnMoO4@CoS core-shell heterostructure is designed and synthesized by stringing metal-organic framework-derived hollow CoS nanocages with MnMoO4 nanorods. Such heterostructure provides more electroactive sites and enhanced structural stability. Theory calculations unveil that the work function difference between MnMoO4 and CoS induces the charge redistribution and modulate interfacial electronic configuration in the MnMoO4/CoS heterojunction. Meanwhile, a interfacial built-in electrical field is established, enhancing interfacial charge transfer efficiency and promoting the surface adsorption of electrolyte ions. By integrating all these advantages, the MnMoO4@CoS electrode demonstrates enhanced rate capacities (933 C g−1 at 1 A g−1 and 623 C g−1 at 10 A g−1) and cycling durability (90.3 % capacity retention after 10,000 cycles) compared to bare MnMoO4 and CoS electrodes. Moreover, the MnMoO4@CoS electrode exhibits an appreciable electrocatalytic performance for methanol oxidation, with a current density of 294.8 mA cm−2 at 10 mV s−1 and 96.6 % current retention after 10,000 s. Our work offers a fundamental guideline for designing and engineering core-shell heterostructures with desirable electrochemical performance for SCs and DMFCs.

Enhancing thermal energy storage efficiency at low temperatures with innovative macro-encapsulation of nano phase change material in cementitious composites

In this study, phase change material (PCM) was encapsulated in a novel aluminium-based macro-capsule and indirectly applied to cement-based mortar to address leakage issues and enhance thermal management. To further improve the thermal efficiency of the PCM, nanofluid technology was utilized by incorporating multi-walled carbon nanotubes (MWCNTs). Thermophysical property tests were conducted to evaluate the thermal properties and stability of the PCM/MWCNT composite. Additionally, thermal cycling tests of the cementitious composites with macro-encapsulated nano-PCM were performed to verify their thermal performance for thermal energy storage under varying ambient temperatures. The results confirmed that the thermal conductivity of the nano-PCM was more than 100 % greater than that of raw PCM. Furthermore, the high-efficiency thermal energy storage cementitious composite was able to maintain the temperature above 0°C when the ambient temperature was −5°C, demonstrating its superior thermal energy storage performance. This innovative approach highlights the potential of the PCM/MWCNT composite for effective thermal regulation in subzero climates, providing a robust solution for enhancing energy efficiency in challenging environmental conditions.