Supercapacitors (SCs) have become increasingly important in electrical energy storage and delivery owing to their high power densities and long lifetimes. Aqueous SCs are promising for large-scale engineering applications because of their low cost and safety. However, the low operating voltage and low energy density of aqueous SCs severely limit their practical applications. In this study, a nanoscale dielectric layer is grafted onto a graphene electrode to achieve both a high operating voltage and enhanced capacitance. Compared with an SC without dielectric grafting, a dielectric-enhanced SC (DESC) shows a higher capacitance by 2200%. The mechanism of the capacitance enhancement can be attributed to three factors: the dielectric polarization, the ions desolvation by the dielectric, and the enhanced quantum capacitance from charge transfer and ion adsorption in the polymer molecules. In addition, a 2.5 V pouch DESC with a 1 M KCl electrolyte is confirmed to cycle up to 50,000 times with a capacitance retention of 87.5%. The DESC presents the optimal electrochemical properties after it is grafted with a 5 nm dielectric layer. This study provides new insights into the design of high-voltage and high-energy-density aqueous SCs.

Lithium (Li) metal batteries (LMBs) can potentially deliver much higher energy density but remain plagued by uncontrollable Li plating with dendrite growth, unstable interfaces, and highly abundant excess Li (> 50 mAh∙cm⁻²). Herein, different from the artificial layer or three-dimensional (3D) matrix host constructions, various dielectric polymers are initially well-comprehensively investigated from experimental characterizations to theoretical simulation to evaluate their functions in modulating Li ion distribution. As a proof of concept, a 3D interwoven high dielectric functional polymer (HDFP) nanofiber network with polar C–F dipole moments electrospun on copper (Cu) foil is designed, realizing uniform and controllable Li deposition capacity up to 5.0 mAh∙cm⁻², thereby enabling stable Li plating/stripping cycling over 1400 h at 1.0 mA∙cm⁻². More importantly, under the high-cathode loading (~ 3.1 mAh∙cm⁻²) and only 0.6 × excess Li (N/P ratio of 1.6), the full cells retain capacity retention of 97.4% after 200 cycles at 3.36 mA∙cm⁻² and achieve high energy density (297.7 Wh∙kg⁻¹ at cell-level) under lean electrolyte conditions (15 μL), much better than ever-reported literatures. Our work provides a new direction for designing high dielectric polymer coating toward high-retention-rate practical Li full batteries.

Self-cleaning is the key factor that makes superhydrophobic nanostructured materials have wide applications. The self-cleaning effect, however, strongly depends on formations and movement of water droplets on superhydrophobic nanostructured surfaces, which is greatly restricted at low humidity (< 7.6 g·kg⁻¹). Therefore, we propose a self-cleaning method at low humidity in which the pollution is electro-aggregated and driven in the electric field to achieve the aggregation and cleaning large areas. The cleaning efficiency of this method is much higher than that of water droplet roll-off, and will not produce “pollution bands”. A simplified numerical model describing pollution movements is presented. Simulation results are consistent with experimental results. The proposed method realizes the self-cleaning of superhydrophobic nanostructured surfaces above dew point curve for the first time, which extends applications of superhydrophobic nanostructured materials in low humidity, and is expected to solve self-cleaning problems of outdoor objects in low humidity areas (< 5.0 g·kg⁻¹).

The development of wearable and portable electronics calls for flexible piezoelectric materials to fabricate self-powered devices. However, a big challenge in piezoelectric material design is to boost the output performance while ensuring its flexibility and biocompatibility. Here, all-organic and core-shell structured silk fibroin (SF)/poly(vinylidene difluoride) (PVDF) piezoelectric nanofibers (NFs) with excellent flexibility are fabricated using a simple electrospinning strategy. The strong intermolecular interaction between SF and PVDF promotes the β-phase nucleation in the core-shell structure, which significantly enhances the output performance. An output of 16.5 ​V was achieved in SF/PVDF NFs, which is more than 6-fold enhancement compared with that of pure PVDF NFs. In addition, the piezoelectric device can sensitively detect the mechanical stimulation from joint bending, demonstrating its great potential in self-powered sensor. Otherwise, the piezoelectric device can be also applied to control the movement of a smart car, successfully, achieving its application in the human-machine interaction.

Boron nitride nanosheets (BNNSs) have gained significant attraction in energy and environment fields because of their two-dimensional (2D) nature, large band gap and high thermal/mechanical performance. However, the current low production efficiency of high-quality BNNSs is still a bottleneck limiting their applications. Herein, based on sonication-assisted liquid-phase exfoliation, we demonstrated a rapid, high-efficient and scalable production strategy of BNNSs and documented the effects of a spectrum of exfoliation factors (e.g., ultrasonic condition, solvent and bulk material feeding) on the yield of BNNSs. A record of yield of 72.5% was achieved while the exfoliated BNNSs have few-layer and defect-free feature. Thanks to the Lewis acid sites of the boron atoms, the BNNSs can interact with the polysulfide anions in liquid electrolyte and also can facilitate the uniform lithium deposition, which finally endow a lithium-sulfur (Li-S) battery with long life. This work provides a facile and rapid strategy for large scale preparation of high-quality BNNSs, also contributes a long-life strategy for dendrite-free Li-S battery, opens new avenues of BNNSs in energy application.

Ultrathin and flexible electromagnetic shielding materials hold great potential in civil and military applications. Despite tremendous research efforts, the development of advanced shielding materials is still needed to provide additional functionalities for various artificial-intelligence-driven systems, such as tactile sensing ability. Herein, a layering design strategy is proposed to fabricate ultrathin Ti₃C₂T_x MXene-aramid nanofiber (MA) films by a layer-by-layer assembling process. Compared to that of randomly mixed films, the designed MA films exhibited a higher EMI shielding efficiency at an ultrathin thickness of 9 μm, which increased from 26.4 to 40.7 dB, owing to the additional multiple-interface scattering mechanism. Importantly, the novel MA films displayed strong EMI shielding ability even after heating/cooling treatments within a wide temperature range of -196 to 300 °C. Moreover, the same material displayed a tensile strength of 124.1 ± 2.7 MPa and a toughness of 6.3 ± 1.1 MJ·m^-3, which are approximately 9.1 times and 45 times higher than those of pure MXene films, respectively. The MA film is also capable of detecting tactile signals via the triboelectric effect. A 2 × 4 tactile sensor array was developed to achieve an accurate signal catching capability. Therefore, in addition to the shielding performance, the manifestation of tactile perception by the MA films offers exciting opportunities in the fields of soft robotics and human-machine interactions.