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Polymer-based dielectric composites show great potential prospects for applications in energy storage because of the specialty of simultaneously possessing the advantages of fillers and polymer matrices. However, polymer-based composites still have some urgent issues that need to be solved, such as lower breakdown field strength (Eb) than polymers, dielectric mismatch, and the poor interface between the matrix and the filler. Hence, this review provides a systematic summary of recent research advances in improving the energy storage properties of polymer-based composites from several aspects, mainly including polymer matrix types, optimization of filler shapes, surface modification of fillers, and design of multi-layer composite structures. Finally, some existing challenges and future perspectives are outlined and discussed to facilitate the further development of polymer-based composites in the energy storage field. We believe this review will help researchers better understand the current development status of polymer-based composites in the energy storage field, and push it forward to a new research stage. [ABSTRACT FROM AUTHOR]

A 1-3 type poly(vinylidene-trifluoroethylene)/lead zirconate titanate (P(VDF-TrFE)/Pb(Zr0.52Ti0.48)O3) piezoelectric composite is prepared using a two-step hot-pressing method, showing a considerable dielectric constant (εr ~ 4614) and a very low dielectric loss factor (tanδ) of 0.05 and at 100 Hz are obtained in PZT/P(VDF-TrFE) sheet with a thickness of 1.2 mm. Because the polarized P(VDF-TrFE) has a clamping pressure on the engineered columnar architecture by the inverse piezoelectric effect, the elongation of PZT is improved by suppressing its lateral vibrations, which is well expressed by COMSOL simulations. As such, an attractive electrical coupling coefficient (kt) of 0.733 is achieved with specific geometric modifications to the PZT/P(VDF-TrFE) sheets. These findings indicate that piezoelectric P(VDF-TrFE) to replace conventional epoxy resin as the polymer matrix offers a route to construct 1-3 type piezoelectric composites. [ABSTRACT FROM AUTHOR]

A group of (0.65Bi0.5Na0.5–0.35Bi0.2Sr0.7)(Ti1−x,Zrx)O3 (BNBS-(Ti1−x,Zrx)) lead-free energy storage ceramic sheets are prepared by a conventional solid-state sintering method. We find that B-site doping of ZrO2 may minimize the grain size while not change the perovskite structure of BNBS-(Ti1−x,Zrx). As such, BNBS-(Ti1−x,Zrx) possesses the uniform grains and clear grain boundaries, resulting in a high dielectric permittivity (εr) of about 2080 and a low dielectric loss (tanδ) of 0.05 at 100 Hz. Due to the lattice distortion caused by Zr4+ entering the TiO6 octahedral lattice, Tm of BNBS-(Ti1−x,Zrx) decreases with the increase of ZrO2 doping content. Attractively, BNBS-(Ti1−x,Zrx) exhibits relatively slender polarization-electric field (P-E) loops at a high electric field of 100 kV/cm, and BNBS-(Ti0.97,Zr0.03) achieves considerable recycle discharging energy density (Wrec) of 1.47 J/cm3 and high efficiency (η) of 86.94%. Thus, as a block ceramic synthesized by convenient process, this result is superior to most of similar BNT-based materials, and may provide a reference for pulse power capacitors. [ABSTRACT FROM AUTHOR]

In order to improve the energy storage performance of Bi-based lead-free ceramics in dielectric capacitors, K0.5Bi0.5TiO3 is doped into Bi0.5Na0.5TiO3-Bi0.2Sr0.7TiO3 (NBT-SBT) ceramics. We find that NBT-SBT-xK0.5Bi0.5TiO3 (NBT-SBT-xBKT, x=0, 0.02, 0.03, 0.05 and 0.08) ceramic sheets maintain the perfect pure perovskite structures and show the character of relaxor ferroelectrics, indicating that the doped K+ ions smoothly infiltrate into the host lattice of binary system NBT-SBT ceramics and then disturb the long-range order of ferroelectric material and cause the lattice deformation in NBT-SBT. As such, the NBT-SBT-0.03BKT ceramic sample obtains dielectric constant (εr) of 1736, dielectric loss (tanδ) of 0.05, and energy storage efficiency (η) of 70.7%, respectively. More strikingly, NBT-SBT-xBKT ceramics exhibit excellent temperature stability, which helps to store energy at high temperatures. This paper can provide an effective method for manufacturing ceramic based capacitors with high energy storage property. [ABSTRACT FROM AUTHOR]

It is well thought that the performance of polyvinylidene fluoride trifluoroethylene [P(VDF-TrFE)] is better than that of oriented polyvinylidene fluoride (oriented PVDF). But the harsh fabrication process or poor stability of P(VDF-TrFE) polymer limits its mass production. Therefore, it is worth making a comparative property assessment of PVDF and P(VDF-TrFE) piezoelectric polymers from the point of view of the practical application. In this work, we have used the oriented PVDF and P(VDF-TrFE) films to prepare an array of flexible piezoelectric and pyroelectric hybrid energy conversion devices. The responses of devices to different scenarios and environments were investigated. It was found that the two energy conversion devices can convert various forms of energy from the external stimulus conditions to get the output electrical signals. However, the two conversion devices exhibited different signal responses to different forms of external stimuli, which provides a reference for the choice of device materials in practical applications. It was confirmed that the oriented PVDF film fabricated by the simple and economical method has also great potential applications as wearable and electronic touch screens and medical monitoring devices. [ABSTRACT FROM AUTHOR]

Recently, for their advantages of lightweight, easy-shaped, good corrosion resistance, biocompatibility, etc., a series of flexible poly (vinylidene fluoride)-based (PVDF-based) piezoelectric composites have been proposed for use in self-powered electronic devices, such as piezoelectric nanogenerators, sensors, wearable electronic units, etc. In this review, we classify the polymer-based piezoelectric composites, combine their preparation method, filler type, structure, and performance, etc., and explain in detail the effects of different preparation methods and filler types on the piezoelectric properties of the composites. Then, the influence of composition, structure, and forming method on the piezoelectric and energy-transforming performances are investigated. Finally, the development trends of these PVDF-based piezoelectric composites are prospected. This review may provide a reference for the academic and application of the polymer-based piezoelectric composites in energy transfer-related and harvesting-related areas. [ABSTRACT FROM AUTHOR]

A group of lead-free (1 − x)(0.65Bi0.5Na0.5TiO3–0.35Sr0.7Bi0.2TiO3)–x[Ba(Zr0.3Ti0.7) O3] [(1 − x)BNT–SBT–xBZT] ternary ceramics is prepared through the traditional solid-phase sintering reaction. The introduction of relaxor dielectric ceramic Ba (Zr0.3Ti0.7)O3 (BZT) can reduce the grain size, form a typical "ferroelectric + relaxor ferroelectric" lead-free system, and refine the hysteresis loops and improve η through site doping. As such, the dielectric anomaly peaks gradually shift to lower temperature and show a diffusion phase transition behavior over a wide temperature range, resulting in an active relaxation with the increase of doping BZT. Remarkably, the high energy density performance (Wrec and η are 1.00 J cm−3 and 87%, respectively) is obtained in this 0.86BNT-SBT-0.14BZT ceramic at relatively low electric field of 80 kV cm−1. This work is an appropriate reference to promote the energy storage performance of BNT-based ceramics by introducing BZT, providing an approach for lead-free dielectric materials. [ABSTRACT FROM AUTHOR]

An environmentally friendly ceramic K0.5Na0.5NbO3 is synthesized using traditional solid-state reaction process, and followed that a group of flexible K0.5Na0.5NbO3/poly(vinylidene fluoride-trifluoroethylene) (KNN/P(VDF-TrFE)) piezoelectric composite films are prepared by a conventional solution casting method. We find 3%-25% doping of KNN in mass ration (wt%) can fabricate the dielectric and ferroelectric properties of the KNN/P(VDF-TrFE) films, and a proper content of 15 wt% of KNN favors of the piezoelectric phase of P(VDF-TrFE) and thereby contributes to the piezoelectric performance of these composite films, effectively. As such, a maximum dielectric constant (εr) of 20.5 and a large residual polarization (Pr) of 13.6 μC/cm2 are obtained in KNN/P(VDF-TrFE) composite film, respectively. Attractively, this composite film exhibits a high-piezoelectric coefficient (d33) of -24 pC/N, and consequently is beneficial to a large output voltage of 3.2 V for pulse stress testing, which provides a referenced material for the prospect of application in energy conversion area. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the efficacy of Everolimus (EVE) in combination with immune checkpoint inhibitors (ICIs) in bladder cancer treatment and the underlying mechanisms. In vitro, MB49 cells were exposed to gradient concentrations (0 nM–100 nM) of EVE for 48 h, to investigate the cell viability and cell proliferative potential. In vivo, we applied a subcutaneous tumor mouse model of bladder cancer and the mice were treated with EVE monotherapy (different doses) or in combination with anti-programmed cell death protein 1 (PD-1) agents to study the impacts on tumor growth and explore the immune mechanism. The influences of treatments on peripheral immune profiles and tumor immune microenvironment were also discussed. EVE could inhibit the growth of MB49 cells in vitro. Though high-dose EVE monotherapy could induce tumor regression in vivo, it also contributed to immunosuppression. High-dose EVE inhibited the expression of PD-L1 by inhibiting Th1 cytokine secretion, while combined therapy with PD-1 inhibitors showed no extra profit. Low-dose EVE in combination with PD-1 inhibitors could effectively suppress tumor growth by increasing periphery CD8+ T cell frequency and GZMB+ CD8+ T cell frequency in the tumor microenvironment. High-dose EVE monotherapy induced tumor regression, but with immunosuppression to some content. Combination therapy with low-dose EVE and PD-1 inhibitor could effectively inhibit the growth of bladder tumors by enhancing the antitumor immunity of CD8+ T cells in both periphery and tumor microenvironment. [ABSTRACT FROM AUTHOR]

Limited benefit population of immune checkpoint inhibitors makes it urgent to screen predictive biomarkers for stratifying the patients. Herein, we have investigated peripheral CD4+ T cell signatures in advanced non-small cell lung cancer (NSCLC) patients receiving anti-PD-1/PD-L1 treatments. It was found that the percentages of IFN-γ and IL-17A secreting naïve CD4+ T cells (Tn), and memory CD4+ T cells (Tm) expressing PD-1, PD-L1 and CTLA-4 were significantly higher in responder (R) than non-responder (NonR) NSCLC patients associated with a longer progression free survival (PFS). Logistic regression analysis revealed that the baseline IFN-γ-producing CD4+ Tn cells and PD-1+CD4+ Tm cells were the most significant signatures with the area under curve (AUC) value reaching 0.849. This was further validated in another anti-PD-1 monotherapy cohort. Conversely, high percentage of CTLA-4+CD4+ Tm cells was associated with a shorter PFS in patients receiving anti-PD-L1 monotherapy. Our study therefore elucidates the significance of functional CD4+ Tn and Tm subpopulations before the treatment in predicting the responses to anti-PD-1 treatment in Chinese NSCLC patients. The fact that there display distinct CD4+ T cell signatures in the prediction to anti-PD-1 and anti-PD-L1 monotherapy from our study provides preliminary evidence on the feasibility of anti-PD-1 and anti-PD-L1 combination therapy for advanced NSCLC patients. [ABSTRACT FROM AUTHOR]

A group of 0.65(Bi0.5Na0.5)TiO3 -0.35(Sr0.7+x + Bi0.2)TiO3 (BNT-S0.7+xBT) composite ceramic pellets are synthesized using a traditional solid sintering method, where a tunable x, the changeable volume of Sr, is to tailor energy storage through the adjustments of the A-site stoichiometry in BNT-S0.7+xBT. We find that a small excess of Sr2+ ions will result in an extensively tuning on the crystal grain size and even contribute to the A-site disorder and charge fluctuation of BNT-S0.7+xBT. As such, the BNT-S0.7+xBT exhibits a minimum average grain size and a highly compact crystal morphology, and thus, BNT-S0.75BT ceramic exhibits a high dielectric constant (εr) of about 5100 at 110 °C. Meanwhile, a relatively thin polarization–electric field (P–E) loop with a high maximum polarization of 42 μC/cm2 and a low remnant electric polarization of 5 μC/cm2 are obtained in a BNT-S0.75BT pellet under 100 kV/cm, corresponding to an energy density of 0.98 J cm−3 and a good η of 70.7%. Attractively, the maximum polarization (Pm) of BNT-S0.75BT ceramic at 25–100 °C hardly decreases, implying excellent temperature stability of polarization performances under high electric field of 100 kV/cm, which favors the energy storage of relaxor ferroelectric ceramics and is valuable to a supercapacitor serving at evaluated high temperature. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to investigate the clinical significance of urinary kidney injury molecule-1 (KIM-1) to monitor renal function in patients with obstructive unilateral ureteral calculi. Methods: Kidneys of 12 male C57BL/6J mice, as well as their urine and plasma specimens, were extracted to detect KIM-1 expressions 24 h after unilateral ureteral obstruction (UUO) construction or sham surgery. Meanwhile, a cohort of 89 patients with unilateral ureteral calculi was retrospectively reviewed. 46 of which received double-J ureteral stent indwelling (group 1) and the remaining 43 were treated conservatively (group 2). Urinary KIM-1 levels in the baseline, 2 h and 1 day after treatments were analyzed. Results: KIM-1 expressions were dramatically higher in mice underwent UUO surgery when compared with the sham group. Clinical data showed urinary KIM-1 levels decreased as time went by for patients in group 1 (1.787 ± 1.081 ng/mL for baseline, 1.668 ± 1.162 ng/mL for 2 h and 0.935 ± 0.526 ng/mL for 1 day after operation; p = 0.0001). Nevertheless, for those in group 2, a mild increase (1.659 ± 0.997 ng/mL, 1.691 ± 0.872 ng/mL and 1.675 ± 0.911 ng/mL, correspondingly; p = 0.9869) was observed. Additionally, a urinary KIM-1 value of 1.04 ng/mL had a sensitivity of 83.1% and specificity of 62.5% to predict the presence of hydronephrosis (95% CI: 0.641–0.873, AUC: 0.757, p < 0.001). Conclusions: Urinary KIM-1 is a sensitive biomarker of post-renal acute kidney injury (AKI) and might predict the presence of hydronephrosis. It can be used as an effective surrogate to monitor renal function. [ABSTRACT FROM AUTHOR]

The dielectric response of poly(styrene-co-acrylonitrile) (PSAN) thin films fabricated by a solution casting process was investigated in this work. Linear dielectric behavior was obtained in PSAN films under an electric field at frequencies from 100 Hz to 1 MHz and temperature of −50°C to 100°C. The polymer films exhibited an intermediate dielectric permittivity of 4 and low dielectric loss (tan  δ) of 0.027. Under 400 MV/m, the energy density of the PSAN films was 6.8 J/cm 3, which is three times higher than that of biaxially oriented polypropylene (BOPP) (about 1.6 J/cm 3). However, their charge–discharge efficiency (about 90%) was rather close to that of BOPP. The calculated effective dielectric permittivity of the PSAN films under high electric field was as high as 9, which may be attributed to the improved displacement of the cyanide groups (–CN) polarized at high electric fields. These high-performance features make PSAN attractive for high-energy-density capacitor applications. [ABSTRACT FROM AUTHOR]

We synthesize a group of three-phase ferroelectric ceramics 0.35(Sr0.7Bi0.2) TiO3–0.65(Bi0.5Na0.5)TiO3–xSr(Mg1/3Nb2/3)O3 (BST–BNT–xSMN) using conventional solid-phase sintering method. When tunning the volume of SMN to 0.01, the ceramic sheet shows homogeneous microcrystal grains and highly dense crystal morphology, which favors a reductive dielectric permittivity (εr) of 2250 and loss of 0.05. Under a high electric field of 100 kV cm−1, the BST–BNT-0.01SMN sample achieves a slender polarization versus electrical field (P–E) loop with saturation and residual polarization of 37.1 µC cm−2 and 3.0 µC cm−2, respectively, corresponding to a high energy density of 1.32 J cm−3 and a large η of 81%. Strikingly, the BST–BNT–xSMN ceramics show the excellent temperature stability below 100 °C, which facilitates energy storage in relaxed ferroelectric ceramics and provides an efficient method for obtaining pulsed power capacitors with excellent energy-recoverable characteristics and high efficiency in BNT-based ceramics.The three-phase ferroelectric ceramics 0.35(Sr0.7Bi0.2)TiO3- 0.65(Bi0.5Na0.5)TiO3-xSr(Mg1/3Nb2/3)O3 (BST- BNT- xSMN) possesses a slender polarization versus electrical field loop with saturation and residual polarization of 37.1 µC cm-2 and 3.0 µC cm-2 respectively at 100 kV cm-1, which corresponds to a high energy density of 1.32 J cm-3 and a large η of 81%.Graphical abstract: We synthesize a group of three-phase ferroelectric ceramics 0.35(Sr0.7Bi0.2) TiO3–0.65(Bi0.5Na0.5)TiO3–xSr(Mg1/3Nb2/3)O3 (BST–BNT–xSMN) using conventional solid-phase sintering method. When tunning the volume of SMN to 0.01, the ceramic sheet shows homogeneous microcrystal grains and highly dense crystal morphology, which favors a reductive dielectric permittivity (εr) of 2250 and loss of 0.05. Under a high electric field of 100 kV cm−1, the BST–BNT-0.01SMN sample achieves a slender polarization versus electrical field (P–E) loop with saturation and residual polarization of 37.1 µC cm−2 and 3.0 µC cm−2, respectively, corresponding to a high energy density of 1.32 J cm−3 and a large η of 81%. Strikingly, the BST–BNT–xSMN ceramics show the excellent temperature stability below 100 °C, which facilitates energy storage in relaxed ferroelectric ceramics and provides an efficient method for obtaining pulsed power capacitors with excellent energy-recoverable characteristics and high efficiency in BNT-based ceramics.The three-phase ferroelectric ceramics 0.35(Sr0.7Bi0.2)TiO3- 0.65(Bi0.5Na0.5)TiO3-xSr(Mg1/3Nb2/3)O3 (BST- BNT- xSMN) possesses a slender polarization versus electrical field loop with saturation and residual polarization of 37.1 µC cm-2 and 3.0 µC cm-2 respectively at 100 kV cm-1, which corresponds to a high energy density of 1.32 J cm-3 and a large η of 81%. [ABSTRACT FROM AUTHOR]