Molecular Semiconductor-Induced Deep Trapping Enables Ultrahigh-Performance Dielectric Elastomers.

Developing dielectric capacitors with both a high power density and a high energy density for application in power electronics has been a long-standing challenge. Glass-ceramics offer the potential of retaining the high relative permittivity of ceramics and at the same time of exhibiting the high dielectric breakdown strength and fast charge/discharge rate of glasses, thus producing concurrently high power and energy densities in a single material. In this work, glass-ceramics are fabricated to achieve simultaneously high power and energy densities, high efficiency, and thermal stability by tuning the glass crystallization process via a suitable nucleating agent and a high oxygen partial pressure. Under the same practical charge-discharge test conditions, the as-prepared glass-ceramics combine the high energy density of ceramics and ultrafast discharge rate of glasses, producing the highest power density among glass- and ceramic-based dielectric materials. This work demonstrates the significant potential of achieving both high power and energy densities in glass-ceramics by optimizing the glass crystallization process.

A hybrid PEMFC/supercapacitor device with high energy and power densities based on reduced graphene oxide/Nafion/Pt electrode

Lithium-Ion Batteries receive growing attention because of their potentially high energy and power density, which are important requirements for automobile applications. Reports agreed that the positive electrode is hereby the performance limiting cell component. NxMyCz (nickel manganese cobalt spinel) is one of the most promising cathode materials, both due to its rather high operating voltage and to either high power or energy density [1]. Hereby, a compromise between high power (thin layers and, i.e., high porosity) and high energy density (thick layers and, i.e., low porosity) has to be reached, in particular for automotive applications. This demands for an extended understanding of the interplay between microstructure parameters and chemical stoichiometry of NMC cathodes on cell performance characteristics. In this study, two NMC - cathodes recovered from commercial high energy and high power cells are analyzed (i) by SEM and X-ray tomography and (ii) by Electrochemical Impedance spectroscopy (EIS). By evaluating the impedance spectra measured at 0 to 40°C and at SOC 0 to SOC 100 by the distribution function of relaxation times (DRT) [2], a physically motivated transition line model [3] was established. The microstructure parameters required for a quantitative analysis of the electrochemical loss processes were obtained by X-ray tomography data. Additionally, the exact composition is determined by energy dispersive X-ray spectroscopy (EDX) investigations The results confirm, that a NMC electrode custom tailored for high energy density is rather thick (70 µm) and made of large low-porous agglomerates of primary particles, as described in [4]. The significant difference between the NMC cathode of a high energy and a high power cell however is not, as expected, a significantly higher porosity, but a sophisticated combination of small carbon black particles and elongated carbon black fibers, enabling high discharge currents. The tortuosity of the electrode pores, which represent the transport pathways for the liquid electrolyte, is low for the high power cell, which raises the effective electrolyte conductivity significantly, when compared to the high energy cell [4]. Furthermore the high power cell features a special compound of two different NxMyCz active materials. By including all the results from EIS, DRT, X-ray tomography and EDX, an evaluation of the influence of composition and microstructure on performance characteristics of the NxMyCz cathodes will be presented.

Novel Na0.5Bi0.5TiO3 based, lead-free energy storage ceramics with high power and energy density and excellent high-temperature stability

Superhigh-rate capacitive performance of heteroatoms-doped double shell hollow carbon spheres

Li ion battery (LIB) and electrochemical capacitor (EC) are considered as the most widely used energy storage systems (ESSs) because they can produce a high energy density or a high power density, but it is a huge challenge to achieve both the demands of a high energy density as well as a high power density on their own. A new hybrid Li ion capacitor (HyLIC), which combines the advantages of LIB and Li ion capacitor (LIC), is proposed. This device can successfully realize a potential match between LIB and LIC and can avoid the excessive depletion of electrolyte during the charge process. The galvanostatic charge-discharge cycling tests reveal that at low current, the HyLIC exhibits a high energy density, while at high current, it demonstrates a high power density. Ragone plot confirms that this device can make a synergetic balance between energy and power and achieve a highest energy density in the power density range of 80 to 300 W kg−1. The cycle life test proves that HyLIC exhibits a good cycle life and an excellent coulombic efficiency. The present study shows that HyLIC, which is capable of achieving a high energy density, a long cycle life and an excellent power density, has the potential to achieve the winning combination of a high energy and power density.

Functionalized interfacial cover design toward pure silicon anode for high power density lithium–ion capacitor

Commercially available carbon cloths (CCs) are promising candidates to construct flexible and wearable electronics. Herein, post‐treated CCs are employed to construct flexible supercapacitors (SCs). CCs are first activated in KOH solution and subsequently thermally annealed, resulting in their unique porous microstructure and a wide potential window up to 2.2 V. Using these binder‐ and current‐collector‐free CCs as the capacitor electrodes, a high‐performance and flexible electrical double‐layer capacitor is constructed. In 1 m KOH aqueous solution, its specific capacitance of as high as 1 967.0 mF cm−2 is obtained at a current density of 30 mA cm−2. Moreover, it exhibits excellent capacitance retention and delivers both high energy density (e.g., 93.38 W h kg−1 at a power density of 3 890 W kg−1) and high power density (e.g., 12 850 W kg−1 at an energy density of 12 W h kg−1). Such binder‐free, easy‐assembling, scalable flexible SCs are thus promising for miniaturized electronic industries in the future.

Simple and scalable production of micro-supercapacitors (MSCs) is crucial to address the energy requirements of miniature electronics. Although significant advancements have been achieved in fabricating MSCs through solution-based printing techniques, the realization of high-performance MSCs remains a challenge. In this paper, graphene-based MSCs with a high power density were prepared through screen printing of aqueous conductive inks with appropriate rheological properties. High electrical conductivity (2.04 × 104 S∙m-1) and low equivalent series resistance (46.7 Ω) benefiting from the dense conductive network consisting of the mesoporous structure formed by graphene with carbon black dispersed as linkers, as well as the narrow finger width and interspace (200 µm) originating from the excellent printability, prompted the fully printed MSCs to deliver high capacitance (9.15 mF∙cm-2), energy density (1.30 µWh∙cm-2) and ultrahigh power density (89.9 mW∙cm-2). Notably, the resulting MSCs can effectively operate at scan rates up to 200 V∙s-1, which surpasses conventional supercapacitors by two orders of magnitude. In addition, the MSCs demonstrate excellent cycling stability (91.6% capacity retention and ~100% Coulombic efficiency after 10,000 cycles) and extraordinary mechanical properties (92.2% capacity retention after 5000 bending cycles), indicating their broad application prospects in flexible wearable/portable electronic systems.

Recent advancements in an electrification of transportation sectors and adoption of renewable energies have increased a demand for energy storage devices with both high power density and energy density as current technologies including Li-ion battery (LIB) and electrical double layer capacitor (EDLC) can deliver either high energy or high power density. To bridge the gap between LIB and EDLC, Li-ion capacitors (LICs) was proposed by Amatucci in 2011[1] by employing a LIB-type electrode as an anode and a EDLC-type electrode as a cathode in carbonate based organic electrolytes containing Li-salts. Li-ions are stored in anode via intercalation process and anions are stored on cathode surface via adsorption. LIC is promised to combines the advantages of two entities by delivering high energy density, high power density, long cycle life, and low self-discharge.[2,3] However, the main challenge in LIC is the disparity in charge storage kinetics arising from the different charge storage mechanism in anode and cathode. To increase Li-ion kinetics in LIB-type electrode, many electrode-engineerings including nanostructuring active materials[4], making composites with carbonaceous nanomaterials[5–8], and utilizing electronically conductive sulfides[9] and nitrides[10] showed promising results. However, in spite of the considerable number of studies focusing on increasing power density of LIB-type electrode, only a few reports investigate the effects of electrolytes on the LIC performances.[11,12] The influences of anions in electrolytes on the LIC performance are indisputable as charge storage of the EDLC-type cathode sololy depends on the anion-adsorptions. Herein, this study explores the roles of different anions in Li-salts, including lithium hexfluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium perchlorate (LiClO4), and lithium bis(trifluoromethanesulfonyl)imide (LiC2F6NO4S2, LiTFSI), on the LIC performance. The prepared electrolytes were tested in a LIC consists of spinel lithium titanate anode (Li4Ti5O12, LTO) and activated carbon cathode (AC). The present study aims to highlight the important parameters to be considered when designing an optimized electrolyte system for LIC applications. [1] G.G. Amatucci, F. Badway, A. Du Pasquier, T. Zheng, J. Electrochem. Soc. 148 (2001) A930 [2] K. Naoi, S. Ishimoto, J. Miyamoto, W. Naoi, Energy Environ. Sci. 5 (2012) 9363 [3] W. Zuo, R. Li, C. Zhou, Y. Li, J. Xia, J. Liu, Adv. Sci. 4 (2017) 1 [4] L. Kong, C. Zhang, J. Wang, W. Qiao, L. Ling, D. Long, Sci. Rep. 6 (2016) 21177 [5] H. Kim, M.-Y. Cho, M.-H. Kim, K.-Y. Park, H. Gwon, Y. Lee, K.C. Roh, K. Kang, Adv. Energy Mater. 3 (2013) 1500 [6] J. Wang, H. Li, L. Shen, S. Dong, X. Zhang, RSC Adv. 6 (2016) 71338 [7] L. Yan, X. Rui, G. Chen, W. Xu, G. Zou, H. Luo, Nanoscale. 8 (2016) 8443 [8] Q. Wang, Z.H. Wen, J.H. Li, Adv. Funct. Mater. 16 (2006) 2141 [9] K. Kato, F.N. Sayed, G. Babu, P.M. Ajayan, 2D Mater. 5 (2018) 25016 [10] R. Wang, J. Lang, P. Zhang, Z. Lin, X. Yan, Adv. Adv. Funct. Mater. 25 (2015) 2270 [11] T. Zhang, B. Fuchs, M. Secchiaroli, M. Wohlfahrt-mehrens, S. Dsoke, Electrochim. Acta. 218 (2016) 163 [12] S. Liu, S. Liu, K. Huang, J. Liu, Y. Li, D. Fang, H. Wang, Y. Xia, J. Solid State Electrochem. 16 (2012) 1631

Dielectric elastomers (Des) are a type of EAPs with unique electrical properties and mechanical properties: high actuation strains and stresses, fast response times, high efficiency, stability, reliability and durability. The excellent figures of merit possessed by dielectric elastomers make them the most performing materials which can be applied in many domains: biomimetics, aerospace, mechanics, medicals, etc. In this paper, we present a kind of electroactive polymer composites based on silicone Dielectric elastomers with a high dielectric constant. Novel high DEs could be realized by means of a composite approach. By filling an ordinary elastomer (e.g. silicone) with a component of functional ceramic filler having a greater dielectric permittivity, it is possible to obtain a resulting composite showing the fruitful combination of the matrix's advantageous elasticity and the filler's high permittivity. Here we add the ferroelectric relaxor ceramics (mainly BaTiO3) which has high dielectric constant (>3000) to the conventional silicone Dielectric elastomers, to get the dielectric elastomer which can exhibit high elastic energy densities induced by an electric field of about 15 MV/m. Tests of the physical and chemical properties of the dielectric elastomers are conducted, which verify our supposes and offer the experimental data supporting further researches.

An ultra-high voltage viologen/Br2 flow battery was designed based on a novel two-electron viologen derivative, a highly-conductive and low-cost porous polyolefin membrane, and an effective complexing agent, making the battery one of the most stable two-electron viologen-based flow batteries with superior energy and power density at the same time.

Ru oxide supercapacitors with high loadings and high power and energy densities

We develop zirconium-templated NiO/NiOOH nanosheets on nickel foam and polypyrrole-embedded in exfoliated carbon fiber cloth as complementary electrodes for an asymmetric battery-type supercapacitor device. We achieve high volumetric energy and power density by the modification of commercially available current collectors (CCs). The modified CCs provide the source of active material, actively participate in the charge storage process, provide a larger surface area for active material loading, need no additional binders or conductive additives, and retain the ability to act as the CC. Nickel foam (NF) CCs are modified by use of a soft-templating/solvothermal treatment to generate NiO/NiOOH nanosheets, where the NF is the source of Ni for the synthesis. Carbon-fiber cloth (CFC) CCs are modified by an electrochemical oxidation/reduction process to generate exfoliated core-shell structures (ECFC). Electropolymerization of pyrrole into the shell structure produces polypyrrole embedded in exfoliated core-shell material (PPy@rECFC). Battery-type supercapacitor devices are produced with NiO/NiOOH@NF and PPy@rECFC as positive and negative electrodes, respectively, to demonstrate the utility of this approach. Volumetric energy densities for the full-cell device are in the range of 2.60-4.12 mWh cm-3 with corresponding power densities in the range of 9.17-425.58 mW cm-3. This is comparable to thin-film lithium-ion batteries (0.3-10 mWh cm-3) and better than some commercial supercapacitors (<1 mWh cm-3).1 The energy and power density is impressive considering that it was calculated using the entire cell volume (active materials, separator, and both CCs). The full-cell device is highly stable, retaining 96% and 88% of capacity after 2000 and 5000 cycles, respectively. These results demonstrate the utility of directly modifying the CCs and suggest a new method to produce high volumetric energy density and power density storage devices.

Dielectric elastomer actuators (DEAs) have emerged as leading candidates for artificial muscles in high-performance soft robotics, simultaneously offering large reversible deformations, excellent mechanical compliance, a fast response, and a high energy density. These features make them ideal for broad applications that require versatile adaptability, lightweight construction, and safe human-machine interactions. Despite their potential, their practical implementation remains hindered by several interrelated challenges, including high driving voltages, poor electromechanical stability, limited power density, and inadequate cycling durability. In addition, scalable fabrication techniques, particularly for large-area compliant electrodes and multilayer device structures, remain underdeveloped. Furthermore, the intrinsic, strongly nonlinear, and rate-dependent behavior of dielectric elastomers complicates accurate modeling and real-time control. This perspective provides a critical overview of recent developments in the material design, manufacturing strategies, and dynamic modeling of DEAs and identifies the key barriers and opportunities across these comprehensive domains. This perspective aims to accelerate the advancement of high-performance DEA systems and inspire innovative solutions for their integration into real-world soft-robot applications.