Yu Wang

Thick electrodes provide a promising solution for high-energy-density electrochemical energy storage devices; however, this potential is blocked by the thickness–performance strong-coupling effect, which is fundamentally caused by the thickness-related challenges in the allocation of the active-material microenvironment components (such as binder, conductive agent, and electrolyte) during conventional wet or dry-electrode processing. Here, by learning from the famous Chinese traditional show of molten iron fireworks that utilizes rod impacts to break molten iron into small sparkles, we surprisingly discover the rod-impact deagglomeration (RIDA) effects of fibers at the microscale world for realizing solid-state nanoparticle dispersion. By harnessing the RIDA effects, a strategy of polymeric nanobinder deposition is proposed to realize the co-deposition of the nanobinder and carbon nanofiber onto the active-material particles for the scalable fabrication of centimeter-thick dry-organized electrodes (DOEs). These DOEs outperform traditional electrodes due to their robust active-material microenvironment with good mechanical stability and unblocked charge transport. Consequently, the DOEs show unexpected thickness–performance weak-decoupling behavior and ultrahigh specific capacitance (317.5 F g–1@0.5 A g–1). Our work establishes a general RIDA mechanism for solid-state nanodispersion and a promising solution for the design and dry fabrication of high-performance thick electrodes for supercapacitors and batteries.

Piezoelectric silk fibroin (SF) shows great potential in fabricating sustainable wearable electronics toward health monitoring and human–machine interfacing, yet the processing difficulty and brittleness restrict its practical applications severely. This study proposes a simple strategy to achieve the boosted piezoelectricity and mechanical properties in electrospun regenerated silk fibroin (RSF) nanofiber mats by adding polyethylene glycol (PEG) with different molecular weights to induce the formation of β-sheets via hydrogen bonding and the regulation of PEG phase morphology. Specifically, RSFs consisting of PEG of 2000 and 1000 Da exhibit a significant improvement in the tensile strength (from 6.1 to 9.92 MPa) and elongation at break (from 5.72% to 117.58%), respectively. Meanwhile, RSFs consisting of PEG with a molecular weight of 2000 and 400 Da show a direct piezoelectric force sensitivity of 0.2 mV/N·μm and 0.14 mV/N·μm respectively, superior to that of pure RSF (0.04 mV/N·μm). The piezoelectric force sensors fabricated with RSFs show potential applications in the detection of diverse human motions, including finger tapping for Morse code, grip strength, and knee flexion. Thus, this work unveils a facile strategy to fabricate RSF-based biodegradable piezoelectric force sensors with a trade-off in processability, mechanical ductility, and piezoelectricity.

A synergistic surface modification strategy enables fabricating BF-based composites with a conductivity of ∼230 S m ⁻¹ , TCR of 0.18% per °C, excellent signal linearity ( R ² > 0.999) within 30–150 °C, and linear pressure sensing within 0–0.5 MPa.

Surface functionalization through advanced skin‐like nanocoating is of great significance due to its tremendous potential in transforming materials technologies. Conventional strategies, including wet‐slurry coatings or vapor depositions, not only involve toxic solvents or expensive/time‐consuming processes, but also lead to weak interfaces. Here, we discover the compelled wetting effects of liquid‐metal (LM) during sponge‐rubbing coating, and propose a strategy of surface in situ compositing (SISC) that combines reactive liquid‐metal and van der Waals (vdW) materials (e.g., graphene and boron nitride) by sequenced sponge‐rubbing. Particularly, the components are in situ composited by the intensive frictional shearing of sponge‐rubbing, forming a robust metal‐conductive skin‐coating with ordered and mechanical interlocking microstructures anchored onto various substrates (e.g., polyimide, PI). For applications, the resultant vdM@PI film has been proven as a high‐performance active composite current collector (ACCC) capable of boosting the energy‐density and safety of batteries, an advanced Joule‐heating material for fast battery thermal‐management, and a photothermal material for efficient solar‐energy conversion.

High‐entropy polymer electrolytes (HEPE) have attracted significant attention owing to their exceptional design flexibility in properties and thin‐film processability. However, building high‐performance HEPE with well controlled nanodomains of multi‐components remains a critical challenge due to serious microphase separation. Here, we report a tri‐phase high‐entropy polymer electrolyte (HEPE) tape featuring ultrafine soft‐rigid gradient nanodomains approaching the single‐chain length scale, to achieve notable simultaneous enhancements in mechanical, electrochemical, and interfacial properties. The HEPE is realized through Li ⁺ ‐bond‐regulated nanophase separation of polyethylene oxide (PEO), poly (methyl methacrylate) (PMMA), and polyvinylidene fluoride‐co‐hexafluoropropylene (PVFH), leading to high‐entropy microstructures at the levels of chain conformation and phase domains. Consequently, the HEPE exhibits a high room‐temperature ionic conductivity of 0.24 mS∙cm ⁻¹ , exceptional mechanical properties (strength of 22.1 ± 2.3 MPa, toughness of 87.7 MJ∙m ⁻³ , elastic recovery of 66.7%), and interfacial adhesion toughness of 325 ± 15 N∙m ⁻² . Benefitting from these properties, the HEPE can generate physico‐electrochemical synergistic effects on stabilizing the lithium metal anode with a long cycling life of 750 h at 0.1 mA∙cm ⁻² . The resultant solid‐state Li|HEPE|NCM811 cell delivers a high capacity of 205.5 mAh∙g ⁻¹ even without stack pressure. This study indicates a promising high‐entropy tri‐component mixing strategy for the design and fabrication of HEPEs.

Annealing increases β-phase crystal contents of poly(vinylidene fluoride-trifluoroethylene) (PVDF-TrFE), thus improving its ferroelectricity and piezoelectricity. However, most studies focus on improving piezoelectricity of wet-processed PVDF-TrFE via long-time annealing. Here, we report a flash annealing strategy to boost piezoelectricity of PVDF-TrFE at a temperature above its Curie temperature, which has never been reported for polymer processing. Specifically, electrospun PVDF-TrFE fiber mats show a piezoelectric coefficient d₃₃ of −70.89 pm/V or −68 pC/N after flash annealing, which are superior to that of the mats annealed for 2 h. Besides, the mechanisms for an improvement of β-phase crystal content during flash annealing was interpreted by in-situ Raman spectroscopy, XRD, Fourier transform infrared spectroscopy, and molecular dynamics simulation. The as-fabricated piezoelectric films show promising applications in energy harvesting, high-frequency vibration. It unveils an intriguing way to significantly boost intrinsic piezoelectricity of PVDF-TrFE toward developing advanced flexible electronics and micro-electro-mechanical systems.

Polyolefin separators have achieved great commercial success but face a big challenge in stabilizing electrode interfaces, which is critical for lithium‐metal batteries. Here, to address this challenge, a resilient sponge‐like separator (RSLS) is fabricated via confined microfluidic phase separation (CMPS) of poly(vinylidene fluoride) solution coated onto a polyolefin‐separator. The results show that the sponge‐like porous network structure of the separator coating is critical for its functions, which has been well‐controlled by the CMPS conditions. The optimized RSLS can significantly improve not only the wettability of various liquid electrolytes, but also the thermal‐shrinkage resistance of the polyolefin substrate. Importantly, the unique resilient pore network structures of the RSLS can effectively regulate the lithium deposition and stabilize the lithium‐metal anode surface, due to its adaptive contact with the anode surface during the notable volume change induced by lithium deposition and stripping. This capability enables extended cycle life and reduces the polarization voltage in Li|RSLS|Cu half‐cells compared to the bare commercial polyolefin‐separator. Furthermore, the NCM|RSLS|Li battery also demonstrates higher discharge specific capacity and notably enhanced cycling stability even at a high rate of 1C. This study uncovers the significance of resilient separators for stabilizing the lithium‐metal anode.

Transforming liquid electrolytes into solids by lithium salt-triggered in situ polymerization-based solidification has been of great interest for the manufacturing of solid-state batteries. However, this strategy faces a tricky obstacle in simultaneously achieving high ionic conductivity and mechanical properties due to the poor controllability of the reaction process and electrolyte microstructures. Here, to overcome this challenge, we propose a neuron-like in situ polysol electrolyte (Neu-iPE) by salt-in-sol cross-linking that realizes a lithium-salt-regulated physical cross-linking of poly(vinylidene fluoride) (PVDF) sol nanoparticles. It is found that lithium salt can effectively regulate the sol-gel transition of PVDF sol, as well as the sol-cross-linking via a salt-in-sol microphase reorganization. Benefiting from the well-controlled neuron-like microstructures, the Neu-iPE integrates the advantages of separator and liquid electrolytes and simultaneously achieves a high room-temperature ion-conductivity of 0.42 mS/cm, mechanical strength of 15.7 MPa, and puncture toughness of 34.4 MJ/m³. Enabled by this Neu-iPE, a component-integrated quasi-solid-state battery is successfully fabricated to achieve structural flexibility and interface stability as compared with conventional batteries. This study on Neu-iPE presents not only a promising alternative to conventional in situ polymerization-based electrolyte solidification but also a salt-in-sol cross-linking strategy for the fabrication of biomimetic functional materials and devices.

Rational design and ultrafast fabrication of high‐throughput thick electrodes are essential for high‐energy and power density batteries. However, it is blocked by the lack of both theory and cost‐effective technologies for regulating the active‐material microenvironment (AMME) that fundamentally controls the ion and electron transport for each active‐material particle. Here, inspired by the Chinese‐acupuncture therapy that employs microneedles to dredge the cell microenvironment, a microneedle‐array templated extrusion (MATE) technology is proposed along with an AMME‐therapy theory to address the above challenges. Specifically, a unique clay‐alike thixotropic (CAT) slurry through sol‐binder is first fabricated with significant capabilities in 3D‐morphing. Enabled by this morphable CAT‐slurry, MATE technology is further developed to rapidly and seamlessly fabricate high‐throughput 3D thick electrodes with customizable ordered ion‐transport channels. Consequently, the optimized 3D thick electrode shows a remarkable improvement in specific capacity by 300% even at an ultrahigh active‐material loading of 60 mg cm ⁻² (ca. 3 times the commercial level). Finally, an AMME therapy theory based on an artificial potential field algorithm for ion‐transport path optimization is established to understand the enhanced ion‐transport dynamics. The proposed AMME‐therapy theory and industry‐friendly MATE technology could advance the design and fabrication of high‐throughput electrodes in batteries and other electrochemical energy‐storage devices.