Excellent Energy Storage Performance Research Articles

Successful In Situ Growth of Conductive MOFs on 2D Cobalt-Based Compounds and Their Electrochemical Performance.

Conductive metal-organic frameworks (cMOFs), as a kind of porous material, are considered to be highly promising materials in the field of electrochemistry due to their excellent conductivity. However, due to the low specific capacitance of pure cMOFs, their application in supercapacitors is limited. By virtue of the high theoretical capacity and excellent chemical stability of Co-based compounds, in this work, cMOFs' M-HHTP (M = Ni, Co, NiCo, HHTP = 2,3,6,7,10,11-hexahydroxytriphenylene) are grown in situ on Co(OH)2, CoP, and Co3O4 nanosheets, resulting in a series of electroactive compounds as electrode materials used in supercapacitors. Among all of the compounds, Ni-HHTP@Co(OH)2 shows the most excellent energy storage performance and outstanding cyclic stability in the application of aqueous asymmetric supercapacitors.

Enhanced Energy Storage in PVDF-Based Nanocomposite Capacitors through (00l)-Oriented BaTiO3 Single-Crystal Platelets.

Flexible nanocomposite dielectrics with inorganic nanofillers exhibit great potential for energy storage devices in advanced microelectronics applications. However, high loading of inorganic nanofillers in the matrix results in an inhomogeneous electric field distribution, thereby hindering the improvement of the energy storage density (Ue) of the dielectrics. Herein, we proposed a strategy that utilized (00l)-oriented barium titanate (BT) single-crystal platelets to fabricate trilayered nanocomposite dielectrics for energy storage applications. The trilayered nanocomposites consisted of two high-permittivity layers of (Ta2O5, Al2O3) codoped TiO2 nanoparticles (Ta-Al@TiO2 nps) dispersed in a poly(vinylidene fluoride) (PVDF) matrix to facilitate large electric displacement and a middle layer of (00l)-oriented BT single-crystal platelets to provide high breakdown strength. Hence, the trilayered PVDF/Ta-Al@TiO2 nps/BT single-crystal platelet nanocomposite film attains an outstanding Ue of 16.9 J cm-3 at 370 kV mm-1, which is ∼625% higher than that of the single-layer PVDF/Ta-Al@TiO2 nps film. Finite element simulation further clarified that the successive inner layer of highly (00l)-oriented BT single-crystal platelets could effectively restrain the propagation of electrical treeing in trilayered nanocomposites. This research offers an effective approach for developing flexible dielectric capacitors with an excellent energy storage performance.

High energy storage properties of (Nb0.5La0.5)4+ complex-ion modified (Ba0.85Ca0.15)(Zr0.10Ti0.90)O3 ceramics

In this work, a traditional solid-state method was adopted to prepare dense Ba[Formula: see text]Ca[Formula: see text][(Zr[Formula: see text]Ti[Formula: see text])[Formula: see text]–(Nb[Formula: see text]La[Formula: see text])x]O3(BCZT–xNL) lead-free relaxation ferroelectrics with excellent energy storage performance (ESP). Remarkably, a large breakdown field strength of BDS ([Formula: see text][Formula: see text]kV/cm) resulting from decreased grain size by double ions doping at the B-site was achieved in BCZT–xNL ceramics. Especially, the BCZT–0.12NL ceramic displays a good recoverable energy density ([Formula: see text]) of 3.1[Formula: see text]J/cm3, a high efficiency of 86.7% ([Formula: see text]) and a superior fatigue resistance, as well as a superior charge–discharge performance ([Formula: see text][Formula: see text]A/cm2, [Formula: see text][Formula: see text]MW/cm3, [Formula: see text][Formula: see text]J/cm3, [Formula: see text][Formula: see text]ns) and good thermal stability. Besides, upon NL doping, the FE to RFE phase transition results in a dielectric behavior traversing the relaxation phase ([Formula: see text]) accompanied by frequency dispersion, which is beneficial to improve ESP. The superior ESP in this work indicates that BCZT–0.12[Formula: see text]NL ceramics are a promising candidate used in energy storage capacitors.

Bi-Interlayer Strategy for Modulating NiCoP-Based Heterostructure toward High-Performance Aqueous Energy Storage Devices.

Nickel-cobalt (NiCo) phosphides (NCPs) possess high electrochemical activity, which makes them promising candidates for electrode materials in aqueous energy storage devices, such as supercapacitors and zinc (Zn) batteries. However, the actual specific capacitance and rate capability of NCPs require further improvement, which can be achieved through reasonable heterostructural design and loading conditions of active materials on substrates. Herein, novel hierarchical Bi-NCP heterogeneous structures with built-in electric fields consisting of bismuth (Bi) interlayers (electrodeposited on carbon cloth (CC)) are designed and fabricated to ensure the formation of uniform high-load layered active materials for efficient charge and ion transport. The resulting CC/Bi-NCP electrodes show a uniform, continuous, and high mass loading (>3.5mg) with a superior capacitance reaching 1200 Fg-1 at 1 Ag-1 and 4129 mFcm-2 at 1 mAcm-2 combined with high-rate capability and durable cyclic stability. Moreover, assembled hybrid supercapacitors (HSCs), supercapatteries, and alkaline Zn-ion (AZBs) batteries constructed using these electrodes deliver high energy densities of 64.4, 81.8, and 319.1 Whkg-1, respectively. Overall, the constructed NCPs with excellent aqueous energy storage performance have the potential for the development of novel transition metal-based heterostructure electrodes for advanced energy devices.

Atomic-Level Matching Metal-Ion Organic Hybrid Interface to Enhance Energy Storage of Polymer-Based Composite Dielectrics.

In this work, a distinctive "metal-ion organic hybrid interface" (MOHI) between polyimide (PI) and calcium niobate (CNO) nanosheets is designed. The metal ions in the MOHI can achieve atomic-level matching not only with the inorganic CNO, but also with the PI chains, forming uniform and strong chemical bonds. These results are demonstrated by experiment and theory calculations. Significantly, the MOHI reduces the free volume and introduces deep traps across the filler-matrix interfacial area, thus suppressing the electric field distortion in PI-based composite dielectrics. Consequently, PI-based dielectric containing the MOHI exhibits excellent energy storage performance. The energy storage densities (Ue) of the composite dielectric reach 9.42 J cm-3 and 4.75 J cm-3 with energy storage efficiency (η) of 90% at 25°C and 150°C respectively, which are 2.6 and 11.6 times higher than those of pure PI. This study provides new ideas for polymer-based composite dielectrics in high energy storage.

Excellent energy storage performance with high breakdown strength in Nb2O5-modified (Bi0.5Na0.5)TiO3-based ceramics

The development of lead-free dielectric capacitors with good energy storage performance and high reliability is of great practical significance for pulsed power systems. In this study, Nb2O5-modified 0.6(Bi0.5Na0.5)TiO3-0.4(Sr0.7Bi0.2)TiO3 (BNT-SBT-xNb, 0 ≤ x ≤ 0.07) ceramics were designed to enhance their energy storage performance and prepared using a hydrothermal method. The results show that Nb doping into the B site of BNT-SBT can induce lattice expansion and promote polar nanoregions, resulting in improved dielectric relaxation behavior. Moreover, the introduction of Nb can lead to the refinement of grain size, the increase in resistivity, the reduction of oxygen vacancies, and the broadening of band gap, thereby significantly enhancing the electrical breakdown strength (Eb). Accordingly, the BNT-SBT-0.05Nb system presents excellent energy storage performance with high Wrec ∼6.26 J/cm3 and η ∼87.9 % under an large Eb of 518 kV/cm in accompany with the wide temperature stability (Wrec and η vary within ±6.8 % and ±3.2 % at 40–100 °C). The significant improvement of Eb and energy storage performance demonstrates that the BNT-SBT-0.05Nb system is a potential candidate for applications in high-energy storage capacitors.

High-temperature dielectric nanocomposite film of 2D Bi4Ti3O12/ABS with excellent energy storage performance

The utilization of high-temperature dielectrics in capacitive energy storage is of great significance in contemporary electronic systems. Nevertheless, the thermal stability of most emerging polymers exhibits a significant decline in their energy storage capacity as temperatures rise. In this study, a unique type of 2D Bi4Ti3O12 nanofillers was synthesized in order to improve the breakdown strength. A nanocomposite consisting of Bi4Ti3O12/poly(acrylonitrile-butadiene-styrene) (ABS) was synthesized with the aim of attaining enhanced dielectric characteristics and energy storage density under elevated temperatures. The Bi4Ti3O12/ABS nanocomposites exhibited notable temperature stability in relation to their dielectric and energy storage capabilities across a temperature range spanning from room temperature to 120 oC. Ultrahigh discharged energy density (Ue) of 12.44 J/cm3 for 3 wt.%- Bi4Ti3O12/ABS nanocomposites and high efficiency of 87% under 550 MV/m were achieved at room temperature. An excellent Ue of 9.12 J/cm3 and high efficiency of 86.2% for 3 wt.%- Bi4Ti3O12/ABS nanocomposites were also observed in 3 wt.%- Bi4Ti3O12/ABS nanocomposites under 450 MV/m at 120 oC, which was 117% and 114% of ABS films. These capacitive performances could match or be higher than previously reported values for high-temperature capacitor applications.

Electrochemical and dielectric analysis of multifunctional GQDs@PEG@Mg-ZnFe2O4 ternary nanohybrid for low-frequency electronics, water splitting, and sustainable energy storage applications

This work explores the potential of GQDs@PEG@Mg-ZnFe2O4 nanocomposite in water splitting and energy storage applications. The synthesized hybrid showed remarkable dielectric properties indicating its potential for low-frequency telecommunications and electronics applications. The impedance spectroscopy disclosed the contribution of grains and grain boundaries in the realization of colossal permittivity (104) in GQDs@PEG@Mg-ZnFe2O4. Moreover, GQDs@PEG@Mg-ZnFe2O4 showed excellent energy storage performance, indicated by its specific capacitance of 100 Fg−1 and a retention ratio of 99 % over 1000 cycles at a 1 Ag−1 current density. GQDs@PEG@Mg-ZnFe2O4 nanohybrid also showed remarkable electrocatalytic activity, both for hydrogen evolution reaction and oxygen evolution reaction. The determined Tafel slope value was found to be 90 mVdec−1 and 110 mVdec−1 at a 10 mA/cm2 current density, respectively. These results highlight the multifunctional nature of the GQDs@PEG@Mg-ZnFe2O4 nanocomposite and its potential as a versatile material to address challenges in both energy storage and conversion technologies.

A Mini Review on Sewage Sludge and Red Mud Recycling for Thermal Energy Storage

Sewage sludge and red mud, as common industrial waste, have become a research hotspot in the field of achieving carbon peaking and carbon neutrality, reducing carbon emissions, and solving environmental problems. However, their treatment and disposal have always been a difficult problem in the environmental field. Utilizing these two materials for thermal energy storage can not only improve energy utilization efficiency but also further reduce carbon emissions during their treatment process, providing a new approach for sustainable development in the industrial sector. This article summarizes the research progress for the resource recovery of sewage sludge and red mud for direct thermal energy recovery and composite phase change energy storage. After proper treatment, sludge and red mud can be directly used as energy storage materials. In addition, sludge and red mud can be combined with phase change materials to prepare composite materials with an excellent energy storage performance. This composite has broad application prospects in fields such as solar energy utilization and building energy efficiency. However, there are still some challenges and issues in this resource recovery and utilization, such as potential environmental pollution during the treatment process, the long-term stability of energy storage materials, and cost-effectiveness, which require further research and resolution. The purpose of this paper is to evaluate the potential of sewage sludge and red mud as energy storage materials, to explore their feasibility and advantages in practical applications, and to reveal the research progress, technical challenges, and future development directions of these two materials in the field of thermal energy storage.

Optimize energy storage performance of NaNbO3 ceramics by multivariable control strategy

NaNbO3 ceramics have broad application prospects in ultra-high power electronic systems, electromagnetic pulses, and other applications. In this study, (1-y)[(1-x)NaNbO3-xSmMg0.5Zr0.5O3]-y(Bi0.5Na0.5)0.7Sr0.3TiO3 (x = 0.06, 0.08 and 0.10)(y = 0.30, 0.35, 0.40 and 0.45) ceramics were fabricated. The effects of the incorporation of SmMg0.5Zr0.5O3 (SMZ) and (Bi0.5Na0.5)0.7Sr0.3TiO3 (BNST) on the energy storage performance, impedance, actual charge and discharge capacity, phase structure and microstructure of the ceramic samples were analyzed. Finally, when x = 0.08, and y = 0.35, the recoverable energy storage density of the sample was 5.8 J/cm3 and a high energy storage efficiency of 88 % was obtained at 545 kV/cm. In addition, the ceramic maintains a stable actual charge and discharge capacity and an extremely fast discharge time (16.1 ns) in a wide temperature range (20–160 °C). These excellent energy-storage performances may be due to the fine grain size and large relaxation and activation energies.

Rational Design of Nanosheet Array-Like Layered-Double-Hydroxide-Derived NiCo2O4 In Situ Grown on Reduced-Graphene-Oxide-Coated Nickel Foam for High-Performance Solid-State Supercapacitors.

The investigation of high-performance supercapacitors is essential for accelerating the development of energy storage devices. In this work, a 3D hierarchical nanosheet array-like nickel cobaltite/reduced graphene oxide/nickel foam composite (NiCo2O4/rGO/NF) was assembled via an aqueous coprecipitation-hydrothermal strategy assisted by citric acid. Benefiting from a NiCo layered-double-hydroxide precursor with an atomic-level lattice confinement effect of metal ions and effective hybridization with rGO, the NiCo2O4/rGO/NF composite is featured as thin NiCo2O4 nanosheets (∼113.6 nm × 11.2 nm) composed of NiCo2O4 nanoparticles (∼10.9 nm) vertically staggered on the surface of a rGO-modified NF skeleton, leading to high surface area, abundant mesoporous structure, and active site exposure. The as-obtained NiCo2O4/rGO/NF was directly used as a binder-free integrated electrode for supercapacitors, achieving an excellent specific capacitance of 2863.4 F g-1 (1503.3 C g-1) at 1 A g-1, a superior rate performance of 2335.2 F g-1 at 20 A g-1, and a stability retention of 91.7% after 5000 cycles. More impressively, a solid-state asymmetric supercapacitor assembled by the present NiCo2O4/rGO/NF integrated electrode as the positive electrode and commercial activated carbon as the negative electrode achieved a high energy density of 69.2 Wh kg-1 at a power density of 800 W kg-1, and the energy density at a peak power density of 20004 W kg-1 still remained at 48.9 Wh kg-1, also showing a good cycling stability of 87.2% retention over 10000 cycles. The present facile synthesis strategy of the as-obtained NiCo2O4/rGO/NF nanosheet array composite can be used for the design and construction of many other transition-metal oxide/graphene/NF composite materials with excellent structural stability and performance in energy storage and other related areas.

A graded structure of silicon/carbon composite powder for highly stable lithium ion battery anode

Silicon has much higher theoretical specific capacity than traditional graphite materials (3579 mAh g−1vs. Graphite: 372mAh g−1). However huge volumetric expansion (∼300%) of silicon seriously reduces its cyclic stability as anode in lithium-ion batteries. Though reduce the size of silicon based composites to nanoscale and tuning their porosity have been extensively studied, above strategies reduce the vibration density of the anode material unsurprisingly, which is not conducive to the advantage of high volumetric capacity anode. In this work, we design a unique graded silicon/carbon powder to maintain excellent energy storage performance at high vibration density. The composite of graded structure is constructed by first particles and second particles. The construction strategy is proved to be adoptable to achieve cost effective production of high performance silicon/carbon composite anode for development of advanced lithium-ion battery. Under the premise of industrial powder materials’ production technologies, a graded structure silicon/carbon composite with optimized synthetic condition shows high-reversible capacity of 827.4 mAh g−1 at 200 mAh g−1 (equal to 1464.5 Ah L−1) and it capacity remains at 715.0 mAh g−1 after 800 cycles, with a capacity retention rate of 86.37%, which shows high cycle life.

Enhanced energy storage performance of Na0.5Bi0.5TiO3-based relaxor ferroelectric ceramics by synergistic optimization strategies

Despite the fact that Na0.5Bi0.5TiO3 (NBT) based lead-free ceramics have attracted widespread interest due to their various advantages, their lower recoverable energy storage density (Wrec) and energy storage efficiency (η) limit their development in pulsed power capacitors. In this work, we propose a synergistic optimization strategy to enhance the energy storage performance of 0.65Na0.5Bi0.5TiO3-0.35SrTiO3(NBST) based lead-free ceramics by introducing Bi0.8La0.2(Ni0.5Zr0.5)O3 (BLNZ) and employing viscous polymer process (VPP). The former converts the macroscopic domains into microscopic domains, limiting the polarization response hysteresis to give a large Pm–Pr. The latter reduces the thickness and porosity of the samples, resulting in a substantial increase in breakdown strength. Ultimately, by stepwise optimization of this strategy, the x = 0.15 ceramic by VPP (0.15VPP) achieves excellent energy storage performance (Wrec = 7.6 J/cm3, η = 92%) under 620 kV/cm and reliable temperature stability from 20-140 °C. The combined excellent results of this study show that our synergistic optimization strategy can effectively enhance the energy storage performance of NBT-based dielectric ceramics and could be further extended to other ceramic materials for pulsed power capacitors.

Synthesis and Electrochemical Properties of One‐Dimensional γ‐MnOOH Nanorods

AbstractMnOOH has received much attention from researchers as a supercapacitor electrode material. In this article, one‐dimensional γ‐MnOOH nanorods were prepared by the hydrothermal method using the redox reaction between MnO4− and Mn2+, and the effects of temperatures on the crystalline phases and electrochemical properties of the samples were investigated. The materials were characterized using XRD, FT‐IR, SEM, TEM, Raman and XPS; electrochemical properties were tested using CV, GCD and EIS. The results show that the reaction temperature plays an important role in the generation of γ‐MnOOH. The samples were pure phases of γ‐MnOOH (M‐140) at the reaction temperature of 140 °C, showing interlaced nanorod morphology, and when the reaction temperature was increased to 180 °C, a mixed phase of MnOOH and Mn3O4 appeared. In contrast, the electrochemical performance of γ‐MnOOH nanorods (M‐140) was superior to the other samples, reaching a specific capacitance of 221 F/g at a current density of 0.2 A/g. The capacitance retention was 93.8 % after charging and discharging the M‐140 2000 times at a current density of 6 A/g. Supercapacitors assembled with γ‐MnOOHand activated carbon (AC) have excellent energy storage performance, and a high energy density of 40.6 Wh/kg is obtained at a power density of 196.7 W/kg.

Excellent Energy Storage Performance of ZnO doped (Pb,La)(Zr,Sn,Ti)O3 Based Antiferroelectric Ceramics at an Ultra‐Low Sintering Temperature of 940 °C

Abstract(Pb,La)(Zr,Sn,Ti)O3‐based antiferroelectric ceramics have excellent energy storage performance(more than 90% efficiency), which make them have great application advantages in the field of ceramic capacitors. However, the sintering temperature of (Pb,La)(Zr,Sn,Ti)O3‐based antiferroelectric ceramics is generally above 1250 °C, which limits application as a material for ceramic capacitors. Cu inner electrode has a low co‐firing temperature and high conductivity and a low cost price, making it more competitive in the field of ceramic capacitor inner electrode. Therefore, the first step is to reduce the sintering temperature of (Pb,La)(Zr,Sn,Ti)O3‐based ceramics to below 1000 °C(co‐firing temperature with Cu inner electrode), which is the key and difficult point. In this paper, Pb0.94La0.02Sr0.04(Zr0.45Sn0.47Ti0.08)0.995O3(PLSZST) antiferroelectric ceramics are doped with ZnO, which effectively reduce the sintering temperature. Among them, PLSZST‐1 wt% ZnO is sintered at an ultra‐low sintering temperature (TSintering = 940 °C), which is 330 °C lower than that of PLSZST(TSintering = 1270 °C) without doping ZnO. At the same time, PLSZST‐1 wt%ZnO obtain a recoverable energy density of 4.26J cm−3 and an energy efficiency of 95.5% at 230 kV cm−1. The pulse discharge energy density (Wdis = 3.92 J cm−3) and discharge time (t0.9 = 351 ns) are obtained at 220 kV cm−1, and the current density (CD = 1338A cm−2) and power density (PD = 134MW cm−3) are obtained at 200 kV cm−1. The results provide a possible material basis for Cu internal electrode ceramic capacitors.

A Cross-linked n-Type Conjugated Polymer with Polar Side Chains Enables Ultrafast Pseudocapacitive Energy Storage.

Pseudocapacitors bridge the performance gap between batteries and electric double-layer capacitors by storing energy via a combination of fast surface/near-surface Faradaic redox processes and electrical double-layer capacitance. Organic semiconductors are an emerging class of pseudocapacitive materials that benefit from facile synthetic tunability and mixed ionic-electronic conduction. Reported examples are mostly limited to p-type (electron-donating) conjugated polymers, while n-type (electron-accepting) examples remain comparatively underexplored. This work introduces a new cross-linked n-type conjugated polymer, spiro-NDI-N, strategically designed with polar tertiary amine side chains. This molecular design aims to synergistically increase the electroactive surface area and boost ion transport for efficient ionic-electronic coupling. Spiro-NDI-N demonstrates excellent pseudocapacitive energy storage performance in pH-neutral aqueous electrolytes, with specific capacitance values of up to 532 F g-1 at 5 A g-1 and stable cycling over 5000 cycles. Moreover, it maintains a rate capability of 307 F g-1 at 350 A g-1 . The superior pseudocapacitive performance of spiro-NDI-N, compared to strategically designed structural analogues lacking either the cross-linked backbone or polar side chains, validates the essential role of its molecular design elements. More broadly, the design and performance of spiro-NDI-N provide a novel strategy for developing high-performance organic pseudocapacitors.

Excellent energy storage performance of lead-based antiferroelectric ceramics via enhancing dielectric breakdown mechanism

Lead-based antiferroelectric (AFE) material with high power density has received extensive attention for potential applications in the energy storage devices. Nevertheless, the presence of a secondary phase reduces the band gap and concentrates a significant localized electric field at the center of the tips of both secondary phases, leads to a poor breakdown electric strength (Eb). Hence, we designed high Eb of (Pb1-1.5xSmx)(Zr0.995Ti0.005)O3 ceramics with high energy performance via enhancing dielectric breakdown mechanism by restraining secondary phase. Density functional theory calculations reveal that the valence and conduction bands of secondary phase are in close proximity to the Fermi level, indicating the smaller band gap of secondary phase is unable to withstand the concentration of local electric fields in this samples, thus leading to obtain a poor Eb. UV–vis absorption spectra experiments demonstrate that the overall band gap increases due to the A-site Sm modification strategy, effectively reducing the secondary phase and resulting in elevated levels of Eb. As a consequence, Eb is remarkably improved from 350 kV/cm into 540 kV/cm with increasing Sm3+ content. A record-high Eb of 520 kV/cm and high recoverable energy storage density of 12.9 J/cm3 (energy efficiency of 77.1 %) are achieved in (Pb0.91Sm0.06)(Zr0.995Ti0.005)O3 (PS6ZT) ceramics by tape-casting method. Concerning the performance of pulse charge–discharge, ultrahigh discharge energy density of 8.5 J/cm3 and excellent power density of 188.53 MW/cm3 are achieved in PS6ZT ceramics. Moreover, outstanding stability behavior with a broad frequency range of 1∼140 Hz and a broad temperature range of 20–120 ℃ are obtained. These results show that enhancing Eb mechanism will be provided a potential option to enhanced energy density for PbZrO3-based AFE ceramics.

High energy storage performance of (1-x)Ba0.5Sr0.5TiO3-xK0.5Na0.5NbO3 ceramics via a combined strategy of fine grains and multiphase polar nanoregions

Electrostatic dielectric capacitors have received great attention due to their ultrafast charging-discharging speed and ultrahigh power density. However, the low energy storage density and efficiency are the main obstacles to their practical applications. In this work, solid solution relaxor ceramics with different proportions of lead-free ferroelectrics Ba0.5Sr0.5TiO3 (BST) and K0.5Na0.5NbO3 (KNN) were prepared. Superior energy storage performance was achieved in the 0.7BST-0.3KNN ceramics with a breakdown strength (Eb) of 510 kV/cm, a recoverable energy storage density (Wrec) of 4.10 J/cm3, and an energy storage efficiency (η) of 80 %, which was fairly stable over the temperature range of 30–100 °C. Since multiple cations with different valence and radius coexist on the equivalent sites (A or B sites) of the solid solutions, the chemical disorder and the corresponding lattice distortion induced the coexistence of cubic, tetragonal, and orthorhombic phases, as well as the appearance of the multiphase polar nanoregions (PNRs), making the ferroelectric hysteresis loops linear. At the same time, ultrafine grains in the ceramics greatly improved the Eb. For achieving excellent energy storage performance, this work demonstrates a potential candidate of (1-x)BST-xKNN lead-free solid solution ceramics and a combined strategy of fine grains and multiphase PNRs.

Highly Reactive Graphene Dispersant and Its Effective Reinforcement for Phase Change Coatings.

High efficient dispersant that meanwhile possesses additional functions is highly desirable for the fabrication of graphene-based composite. In this paper, a new reactive dispersant, multi-silanols grafted naphthalenediamine (MSiND), is synthesized, which shows superiority compared with conventional dispersants. It can not only stabilize graphene in water at a high concentration of up to 16mgmL-1 , but also simultaneously be applicable for ethanol medium, in which the graphene concentration can be as high as 12mgmL-1 at the weight ratio of 1:1 (MSiND:graphene). The dispersion is compatible with multi-matrixes and affinity to various substrates. In addition, MSiND exhibits excellent reactivity due to the existence of high-density silanol groups. Tough graphene coatings are constructed on glass slides and non-woven fabric simply by direct painting and dip-coating. Moreover, with the assistance of MSiND, graphene-doped phase-change coatings on hydrophobic non-woven fabric (e.g., functional mask) are prepared via the spray method. The composite coatings show enhanced mechanical strength and excellent energy storage performance, exhibiting great potential in heat preservation and thermotherapy.

In Situ polymerized polyetherimide/Al2O3 nanocomposites with significantly improved capacitive energy storage performance at high temperatures

High-temperature polymer nanocomposites with high energy storage density (Ue) are promising dielectrics for capacitors used in electric vehicles, aerospace, etc. However, filler agglomeration and interface defects at high filler loadings significantly limit the enhancement of Ue and hamper the large-scale production of the nanocomposites. Here, polyetherimide (PEI) nanocomposites with nanoscale alumina (AO) at ultra-low contents were prepared via in situ polymerization from PEI monomers. We compared two composite dielectric preparation methods (in situ polymerization and ordinary solution blending) under the same conditions. In contrast to the nanocomposites obtained by blending PEI polymers with AO, the in situ nanocomposites exhibit substantially improved filler dispersion, together with largely suppressed conduction loss at high fields and high temperatures, leading to comprehensive enhancements of breakdown strength (Eb), charge-discharge efficiency (η) and Ue, simultaneously. The 0.3%(in volume) AO filled PEI nanocomposite film exhibits a superior Ue of 4.8 J/cm3 with η of 90% at 150 °C, which is 128% and 218% higher than those of pristine PEI and the ex situ PEI/AO nanocomposite film under the same conditions, respectively. This work provides a scalable strategy for the preparation of dielectrics with both good processability and excellent high-temperature energy storage performance.