Accelerated Li+ Desolvation for Diffusion Booster Enabling Low-Temperature Sulfur Redox Kinetics via Electrocatalytic Carbon-Grazfted-CoP Porous Nanosheets

Lithium–sulfur (Li–S) batteries are famous for their high energy density and low cost, but prevented by sluggish redox kinetics of sulfur species due to depressive Li ion diffusion kinetics, especially under low-temperature environment. Herein, a combined strategy of electrocatalysis and pore sieving effect is put forward to dissociate the Li⁺ solvation structure to stimulate the free Li⁺ diffusion, further improving sulfur redox reaction kinetics. As a protocol, an electrocatalytic porous diffusion-boosted nitrogen-doped carbon-grafted-CoP nanosheet is designed via forming the N Co P active structure to release more free Li⁺ to react with sulfur species, as fully investigated by electrochemical tests, theoretical simulations and in situ/ex situ characterizations. As a result, the cells with diffusion booster achieve desirable lifespan of 800 cycles at 2 C and excellent rate capability (775 mAh g⁻¹ at 3 C). Impressively, in a condition of high mass loading or low-temperature environment, the cell with 5.7 mg cm⁻² stabilizes an areal capacity of 3.2 mAh cm⁻² and the charming capacity of 647 mAh g⁻¹ is obtained under 0 °C after 80 cycles, demonstrating a promising route of providing more free Li ions toward practical high-energy Li–S batteries.     

The Edge Effects Boosting Hydrogen Evolution Performance of Platinum/Transition Bimetallic Phosphide Hybrid Electrocatalysts

Platinum (Pt) is regarded as a promising electrocatalyst for hydrogen evolution reaction (HER). However, its application in an alkaline medium is limited by the activation energy of water dissociation, diffusion of H⁺, and desorption of H*. Moreover, the formation of effective structures with a low Pt usage amount is still a challenge. Herein, guided by the simulation discovery that the edge effect can boost local electric field (LEF) of the electrocatalysts for faster proton diffusion, platinum nanocrystals on the edge of transition metal phosphide nanosheets are fabricated. The unique heterostructure with ultralow Pt amount delivered an outstanding HER performance in an alkaline medium with a small overpotential of 44.5 mV and excellent stability for 80 h at the current density of −10 mA cm⁻². The mass activity of as-prepared electrocatalyst is 2.77 A mg⁻¹_Pt, which is 15 times higher than that of commercial Pt/C electrocatalysts (0.18 A mg⁻¹_Pt). The density function theory calculation revealed the efficient water dissociation, fast adsorption, and desorption of protons with hybrid structure. The study provides an innovative strategy to design unique nanostructures for boosting HER performances via achieving both synergistic effects from hybrid components and enhanced LEF from the structural edge effect.     

Electrocatalysis of Fe-N-C Bonds Driving Reliable Interphase and Fast Kinetics for Phosphorus Anode in Sodium-Ion Batteries

Phosphorus exhibits high capacity and low redox potential, making it a promising anode material for future sodium-ion batteries. However, its practical applications are confined by poor durability and sluggish kinetics. Herein, an innovative in-situ electrochemically self-driven strategy is presented to embed phosphorus nanocrystal (≈10 nm) into a Fe-N-C-rich 3D carbon framework (P/Fe-N-C). This strategy enables rapid and high-capacity sodium ion storage. Through a combination of experimental assistance and theoretical calculations, a novel synergistic catalytic mechanism of Fe-N-C is reasonably proposed. In detail, the electrochemical formation of Fe-N-C catalytic sites facilitates the release of fluorine in ester-based electrolyte, inducing Na⁺-conducting-enhanced solid-electrolyte interphase. Furthermore, it also effectively induces the dissociation energy of the P-P bond and promotes the reaction kinetics of P anode. As a result, the unconventional P/Fe-N-C anode demonstrates outstanding rate-capability (267 mAh g⁻¹ at 100 A g⁻¹) and cycling stability (72%, 10 000 cycles). Notably, the assembled pouch cell achieves high-energy density of 220 Wh kg⁻¹.     

Engineering Se/N Co-Doped Hard CNTs with Localized Electron Configuration for Superior Potassium Storage

The earth-abundant hard carbons have drawn great concentration as potassium-ion batteries (KIBs) anode materials because of their richer K-storage sites and wider interlayer distance versus graphite, but suffer from a low electrochemical reversibility. Herein, the novel Se/N co-doped hard-carbon nanotubes (h-CNTs) with localized electron configuration are demonstrated by creating unique N Se C covalent bonds stemmed from the precise doping of Se atoms into carbon edges and the subsequent bonding with pyrrole-N. The strong electron-donating ability of Se atoms on d-orbital provides abundant free electrons to effectively relieve charge polarization of pyrrole-N-C bonds, which contributes to balance the K-ion adsorption/desorption, therefore greatly boosting reversible K-ion storage capacity. After filtering into self-standing anodes with weights of 1.5–12.4 mg cm⁻², all of them deliver a high reversible gravimetric capacity of 341 ± 4 mAh g⁻¹ at 0.2 A g⁻¹ and a linear increasing areal capacity to 4.06 mAh cm⁻². The self-standing anode can still maintain 209 mAh g⁻¹ at 8.0 A g⁻¹ (93.3% retention) for a long period of 2000 cycles with a constant Se/N content.     

Revealing the Synergy of Cation and Anion Vacancies on Improving Overall Water Splitting Kinetics

The exact understanding for each promotional role of cation and anion vacancies in bifunctional water splitting activity will assist in the development of an efficient activation strategy of inert catalysts. Herein, systematic first-principles computations demonstrate that the synergy of anion–oxygen and cation–manganese vacancies (V_O and V_Mn) in manganese dioxide (MnO₂) nanosheets results in abnormal local lattice distortion and electronic modulation. Such alterations enrich the accessible active centers, increase conductivity, enhance the water dissociation step, and favor intermediate adsorption–desorption, consequently promoting HER and OER kinetics. As proof of concept, robust electrocatalysts, MnO₂ ultrathin nanosheets doped with dual vacancies (DV–MnO₂) are obtained via a maturely chemical strategy. Detailed characterizations confirm the cation vacancies-V_Mn contribute to enhanced conductivity and anion vacancies-V_O enrich the active centers with optimized local electronic configurations, consistent with the simulative predictions. As expected, DV–MnO₂ exhibits exceptional bifunctionality with the strong assistance of synergetic dual vacancies which act as abundant “hot spots” for active multiple intermediates. Leading to a lower cell voltage (1.55 V) in alkali electrolyte is required to reach 10 mA cm⁻² for the overall water splitting system. These atomic-level insights on synergetic DV can favor the development of activating strategy from inert electrocatalysts.     

Tandem Carbon Hollow Spheres with Tailored Inner Structure as Sulfur Immobilization for Superior Lithium–Sulfur Batteries

The construction of lithium–sulfur battery cathode materials while simultaneously achieving high areal sulfur-loading, adequate sulfur utilization, efficient polysulfides inhibition, rapid ion diffusion, etc. remains a major challenge. Herein, an internal regulatory strategy to fabricate the unique walnut-like yolk–shell carbon flower@carbon nanospheres is presented (WSYCS) as sulfur hosts. The internal carbon flower, suitable cavity, and external carbon layer effectively disperse the insulate sulfur, accommodate volumetric expansion, and confine polysulfides, thus improving the performance of lithium–sulfur batteries. The finite element simulation method also deduces the enhanced Li⁺ diffusion and lithium–sulfur reaction kinetics. More importantly, WSYCS2 is grafted onto carbon fiber (CF) by electro-spinning method to form a tandem WSYCS2@CF 3D film as a sulfur host for the free-standing electrode. The corresponding battery exhibits an extremely high areal capacity of 15.5 mAh cm⁻² with a sulfur loading of 13.4 mg cm⁻². Particularly, the flexible lithium–sulfur pouch cell delivers a high capacity of 8.1 mAh cm⁻² and excellent capacity retention of 65% over 800 cycles at a relatively high rate of 1C, corresponding to a calculated energy density of 539 Wh kg⁻¹ and 591 Wh L⁻¹. This work not only provides guidance for tailoring thick carbon/sulfur electrodes but also boosts the development of practical lithium–sulfur batteries.     

Flexible Carbon Dots-Intercalated MXene Film Electrode with Outstanding Volumetric Performance for Supercapacitors

2D MXenes have emerged as promising supercapacitor electrode materials due to their metallic conductivity, pseudo-capacitive mechanism, and high density. However, layer-restacking is a bottleneck that restrains their ionic kinetics and active site exposure. Herein, a carbon dots-intercalated strategy is proposed to fabricate flexible MXene film electrodes with both large ion-accessible active surfaces and high density through gelation of calcium alginate (CA) within the MXene nanosheets followed by carbonization. The formation of CA hydrogel within the MXene nanosheets accompanied by evaporative drying endow the MXene/CA film with high density. In the carbonization process, the CA-derived carbon dots can intercalate into the MXene nanosheets, increasing the interlayer spacing and promoting the electrolytic diffusion inside the MXene film. Consequently, the carbon dots-intercalated MXene films exhibit high volumetric capacitance (1244.6 F cm⁻³ at 1 A g⁻¹), superior rate capability (662.5 F cm⁻³ at 1000 A g⁻¹), and excellent cycling stability (93.5% capacitance retention after 30 000 cycles) in 3 m H₂SO₄. Additionally, an all-solid-state symmetric supercapacitor based on the carbon dots-intercalated MXene film achieves a high volumetric energy density of 27.2 Wh L⁻¹. This study provides a simple yet efficient strategy to construct high-volumetric performance MXene film electrodes for advanced supercapacitors.     

Hierarchical Design of Cross-Linked NiCo2S4 Nanowires Bridged NiCo-Hydrocarbonate Polyhedrons for High-Performance Asymmetric Supercapacitor

Engineering core-shell materials with rationally designed architectures and components is an effective strategy to fulfill the high-performance requirements of supercapacitors. Herein, hierarchical candied-haws-like NiCo₂S₄@NiCo(HCO₃)₂ core-shell heterostructure (NiCo₂S₄@HCs) is designed with NiCo(HCO₃)₂ polyhedrons being tightly strung by cross-linked NiCo₂S₄ nanowires. This rational design not only creates more electroactive sites but also suppresses the volume expansion during the charge–discharge processes. Meanwhile, density functional theory calculations ascertain that the formation of NiCo₂S₄@HCs heterostructure simultaneously facilitates OH⁻ adsorption/desorption and accelerates electron transfer within the electrode, boosting fast and efficient redox reactions. Ex situ X-ray diffraction and Raman measurements reveal that gradual phase transformations from NiCo(HCO₃)₂ to NiCo(OH)₂CO₃ and then to highly-active NiCoOOH take place during the cycles. Therefore, NiCo₂S₄@HCs demonstrates an ultrahigh capacitance of 3178.2 F g⁻¹ at 1 A g⁻¹ and a remarkable rate capability of 2179.3 F g⁻¹ at 30 A g⁻¹. In addition, the asymmetric supercapacitor NiCo₂S₄@HCs//AC exhibits a high energy density of 69.6 W h kg⁻¹ at the power density of 847 W kg⁻¹ and excellent cycling stability with 90.2% retained capacitance after 10 000 cycles. Therefore, this novel structural design has effectively manipulated the interface charge states and guaranteed the structural integrity of electrode materials to achieve superior electrochemical performances.     

Electron Transfer-Induced Metal Spin-Crossover at NiCo2S4/ReS2 2D–2D Interfaces for Promoting pH-universal Hydrogen Evolution Reaction

The development of an efficient pH-universal hydrogen evolution reaction (HER) electrocatalyst is essential for practical hydrogen production. Here, an efficient and stable pH-universal HER electrocatalyst composed of the strongly coupled 2D NiCo₂S₄ and 2D ReS₂ nanosheets (NiCo₂S₄/ReS₂) is demonstrated. The NiCo₂S₄/ReS₂ 2D–2D nanocomposite is directly grown on the surface of the carbon cloth substrate, which exhibits excellent HER performance with overpotentials of 85 and 126 mV at a current density of 10 mA cm⁻² and Tafel slopes of 78.3 and 67.8 mV dec⁻¹ under both alkaline and acidic conditions, respectively. Theoretical and experimental characterizations reveal that the chemical coupling between NiCo₂S₄ and ReS₂ layers induces electron transfer from Ni and Co to interfacial Re-neighbored S atoms, enabling beneficial H atom adsorption and desorption for both acidic and alkaline HER. Simultaneously, an electron transfer-induced spin-crossover generates high-spin interfacial Ni and Co atoms that promote water dissociation kinetics at the NiCo₂S₄/ReS₂ interface, which is the origin of the superior alkaline HER activity. NiCo₂S₄/ReS₂ also shows decent catalytic activity and long-term durability for oxygen evolution reaction, and finally bifunctionality for overall water splitting. This study suggests a rational strategy to enhance water dissociation kinetics by inducing spin-crossover via electron transfer.     

Water-gated phthalocyanine transistors: Operation and transduction of the peptide–enzyme interaction

The use of aqueous solutions as the gate medium is an attractive strategy to obtain high charge carrier density (10¹² cm⁻²) and low operational voltages (<1 V) in organic transistors. Additionally, it provides a simple and favorable architecture to couple both ionic and electronic domains in a single device, which is crucial for the development of novel technologies in bioelectronics. Here, we demonstrate the operation of transistors containing copper phthalocyanine (CuPc) thin-films gated with water and discuss the charge dynamics at the CuPc/water interface. Without the need for complex multilayer patterning, or the use of surface treatments, water-gated CuPc transistors exhibited low threshold (100 ± 20 mV) and working voltages (<1 V) compared to conventional CuPc transistors, along with similar charge carrier mobilities (1.2 ± 0.2) x 10⁻³ cm² V⁻¹ s⁻¹. Several device characteristics such as moderate switching speeds and hysteresis, associated with high capacitances at low frequencies upon bias application (3.4–12 μF cm⁻²), indicate the occurrence of interfacial ion doping. Finally, water-gated CuPc OTFTs were employed in the transduction of the biospecific interaction between tripeptide reduced glutathione (GSH) and glutathione S-transferase (GST) enzyme, taking advantage of the device sensitivity and multiparametricity.     

Non-Interpenetrated 3D Covalent Organic Framework with Dia Topology for Au Ions Capture

The 3D covalent organic frameworks (COFs) have attracted considerable attention owing to their unique structural characteristics. However, most of 3D COFs have interpenetration phenomena, which will result in decreased surface area and porosities, and thus limited their applications in molecular/gas capture. Developing 3D COFs with non-fold interpenetration is challenging but significant because of the existence of non-covalent interactions between the adjacent nets. Herein, a new 3D COF (BMTA-TFPM-COF) with dia topology and non-fold interpenetration for Au ion capture is first demonstrated. The constructed COF exhibits a high Brunauer–Emmett–Teller surface area of 1924 m² g⁻¹, with the pore volume of 1.85 cm³ g⁻¹. The high surface area and abundant cavities as well as the abundant exposed CN linkages due to the non-interpenetration enable to absorb Au³⁺ with high capacity (570.18 mg g⁻¹), selectivity (99.5%), and efficiency (68.3% adsorption of maximum capacity in 5 min). This work provides a new strategy to design 3D COFs for ion capture.     

Bioinspired Fractal Design of Waste Biomass-Derived Solar–Thermal Materials for Highly Efficient Solar Evaporation

Solar evaporation is considered a promising technology to address the issue of fresh water scarcity. Although many efforts have been directed towards increasing the solar–thermal conversion efficiency, there remain challenges to develop efficient and cost-effective solar–thermal materials from readily available raw materials. Furthermore, further structural modification of the original biomass structure, particularly at multiple length scales, are seldom reported, which may further improve the solar–thermal performance of these material systems. Herein, a novel low-cost system is developed based on a common bio-waste, pomelo peels (PPs), through a bioinspired fractal structural design strategy, fractal carbonized pomelo peels (FCPP). This FCPP system shows an extremely high solar spectrum absorption of ≈98%, and marvelous evaporation rate of 1.95 kg m⁻² h⁻¹ with a solar–thermal efficiency of 92.4%. In addition, the mechanisms of the evaporation enhancement by fractal structural design are identified by numerical and experimental methods. Moreover, using FCPP in solar desalination shows great superiority in terms of cost and its potential in sewage treatment is also studied. The present work is an insightful attempt on providing a novel proposal to develop bio-waste-derived solar–thermal materials and construct biomimetic structures for efficient solar evaporation and applications.     

Zwitterion Functionalized Graphene Oxide/Polyacrylamide/Polyacrylic Acid Hydrogels with Photothermal Conversion and Antibacterial Properties for Highly Efficient Uranium Extraction from Seawater

In this study, graphene oxide (GO) and polyacrylamide/polyacrylic acid (PAM/PAA) are used to prepare hydrogels with photothermal conversion properties for highly efficient uranium extraction from seawater. Zwitterionic 2-methacryloyloxy ethyl phosphorylcholine (MPC) is introduced in the PAM/PAA/GO hydrogel to obtain PAM/PAA/GO/MPC (PAGM), exhibiting good antibacterial properties. PAGM demonstrates efficient and specific adsorption of uranium (VI) (U(VI)). Under light conditions, the adsorption capacity of PAGM reaches 196.12 mg g⁻¹ (pH = 8, t = 600 min, C₀ = 99.8 mg L⁻¹, m/v = 0.5 g L⁻¹). The adsorption capacity is only 160.29 mg g⁻¹ under dark conditions (pH = 8, t = 600 min, C₀ = 99.8 mg L⁻¹, m/v = 0.5 g L⁻¹). The adsorption capacity of light is 22.5% higher than that of dark. The adsorption process is fitted using the Langmuir and pseudo-second-order models. Furthermore, PAGM exhibits good repeatability and stability after five adsorption–desorption cycles. PAGM exhibits a U(VI) adsorption capacity of 6.1 mg g⁻¹ after storage for one month in natural seawater. The X-ray photoelectron spectroscopy (XPS) results demonstrate that the coordination of the amino, carboxyl, and hydroxyl groups with U(VI) is the primary mechanism of U(VI) adsorption. The mechanism is confirmed through detailed density functional theory calculations. PAGM demonstrates durability, high efficiency, photothermal conversion properties, and antibacterial properties. Thus, it is a promising candidate for uranium extraction from seawater.     

Preparation and characterization of bifunctional BiOClxIy solid solutions with excellent adsorption and photocatalytic abilities for removal of organic dyes

A series of BiOCl_xI_y solid solutions with bifunctional properties was prepared by a hydrolysis method. When used as potential adsorbents for removal of dyes in wastewater, the as prepared samples exhibited the excellent adsorption and photocatalytic abilities, which indicated that the removal ability had been restored completely without centrifugal separating or other chemical desorption methods. Especially to the sample 301 prepared with a 3:1 M ratio of Cl to I, its adsorption capacity could reach nearly 5.0 mg g⁻¹ within 5 min, which was at least 3 times larger than that of the individual BiOX (ca. 1.3 mg g⁻¹), and its degradation efficiency of high concentration (20 mg L⁻¹) methyl orange (MO) was up to 100% after 50 min of visible light irradiation. The relevant characterization results revealed that not only high specific surface area but also the electron structure of interlayer could be the key factors for the high adsorption ability. The possible mechanism was also discussed.     

Efficient Charge Storage in Zinc–Iodine Batteries based on Pre-Embedded Iodine-Ions with Reduced Electrochemical Reaction Barrier and Suppression of Polyiodide Self-Shuttle Effect

Aqueous zinc Iodine batteries are considered as a promising energy storage system due to their high energy/power density, and safety. However, polyiodide shuttling leads to severe active mass loss, which results in lower Coulombic efficiency and limits the cyclic life. Herein, a novel structure-limiting strategy to pre-embed iodide ions into Prussian blue (PBI) is proposed. The DFT calculations and electrochemical characterization reveal that the formation of Ferrum Iodine bond reduces the electrochemical reaction energy barrier of subsequent iodide-ions at the pre-embedding sites, improves the I⁻ oxidation reaction kinetic process, and suppresses the polyiodide self-shuttle. The PBI//Zn batteries exhibit a low Tafel slope (155 mV dec⁻¹). Moreover, UV–vis spectroscopy confirms that the proposed strategy suppresses the polyiodide self-shuttle. As a result, the PBI//Zn battery achieves high iodide utilization and Coulomb efficiency (242 mAh g⁻¹ at 0.2 A g⁻¹, CEs ≈ 100%), as well as high multiplicity performance of 197.2 mAh g⁻¹ even at 10 A g⁻¹(82% of initial capacity). The PBI//Zn battery also renders excellent cyclic stability with a capacity retention of 94% at 4 A g⁻¹ after 1500 cycles. The device exhibits a high energy density of 142 W h kg⁻¹ at a power density of 5538 W kg⁻¹.     

Flexible all fluorescence white organic light emitting device with over 22% EQE by stepped reverse intersystem crossing channels based on ternary exciplex

Improvement of the utilization of triplet excitons for thermally activated delayed fluorescence (TADF) emitter-based white organic light emitting devices (WOLEDs) is a key scientific challenge. In this study, a new strategy with stepped reverse intersystem crossing (RISC) channels induced by new ternary exciplex was proposed to enhance up-conversion of non-radiative triplet excitons. A flexible TADF WOLED with external quantum efficiency (EQE) of 22.7% and a power efficiency of 62.5 lmW⁻¹ was demonstrated. At 1000 cdm⁻², the EQE still remained at 21.4%, showing low efficiency roll-off of 5.7%. It is attributed to the reduced non-radiative triplet excitons stack, which suppressed the triplet–triplet quenching. Moreover, the new ternary exciplex-based WOLED system mCP: DMAC-DPS:PO-T2T:4CZPNPh exhibited rate constant of RISC process of 2.5 × 10⁶ s⁻¹, and about 2 times photoluminescence quantum yield over binary exciplex. The high efficiency effectively demonstrated that the proposed multiple triplet excitons capture process is an effective strategy to improve the utilization of triplet excitons. Moreover, the novel strategy can be a promising approach for the further development of WOLED.     

Bioinspired Intelligent Solar-Responsive Thermally Conductive Pyramidal Phase Change Composites with Radially Oriented Layered Structures toward Efficient Solar–Thermal–Electric Energy Conversion

To remedy the drawbacks of weak solar-thermal conversion capability, low thermal conductivity, and poor structural stability of phase change materials, pyramidal graphitized chitosan/graphene aerogels (G-CGAs) with numerous radially oriented layers are constructed, in which the long-range radial alignment of graphene sheets is achieved by a novel directional-freezing strategy. A G-CGA/polyethylene glycol phase change composite exhibits a thermal conductivity of 2.90 W m⁻¹ K⁻¹ with a latent heat of 178.8 J g⁻¹, and achieves a superior solar-thermal energy conversion and storage efficiency of 90.4% and an attractive maximum temperature of 99.7 °C under a light intensity of 200 mW cm⁻². Inspired by waterlilies, solar-responsive phase change composites (SPCCs) are designed for the first time by assembling the G-CGA/polyethylene glycol phase change composites with solar-driven bilayer films, which bloom by day and close by night. The heat preservation effect of the solar-driven films leads to a higher temperature of SPCC for a longer period at night. The SPCC-based solar–thermal–electric generator achieves output voltages of 499.2 and 1034.9 mV under light intensities of 200 and 500 mW cm⁻², respectively. Even after stopping the solar irradiation, the voltage output still occurs because of the latent heat release and the heat preservation of the films.     

Metallic Zinc Anode Working at 50 and 50 mAh cm−2 with High Depth of Discharge via Electrical Double Layer Reconstruction

Achieving high-rate and high-areal-capacity Zn anode with high depth of discharge (DOD) offers a bright future for large-scale aqueous batteries. However, Zn deposition suffers from severe dendrite growth and side reactions, which compromises achievable lifetime. Herein, an electrical double layer (EDL) reconstruction strategy is proposed by employing acetone as electrolyte additive to fully address these issues. Experimental and theoretical simulation results reveal that the adsorption priority of acetone to water on Zn creates a water-poor inner Helmholtz layer. Meanwhile, the intense hydrogen bonding effect between acetone and water confines the activity of free water and weakens the Zn²⁺ solvation in the outer Helmholtz layer and diffusion layer. Such ion/molecule rearrangement in EDL suppresses hydrogen evolution, facilitates the desolvation process, and promotes the Zn²⁺ diffusion kinetics, which guides homogeneous Zn nucleation and uniform growth, even in extreme situations. At both ultrahigh current density of 50 mA cm⁻² and areal capacity of 50 mAh cm⁻², the addition of 20 v/v% acetone in 2 m ZnSO₄ extends the lifespan of Zn//Zn symmetric cells from 12 to 800 h, with a high DOD of 73.5%. The effectiveness of this strategy is further demonstrated in the Zn-MnO₂ full batteries at wide temperature range from −30 to 40 °C.     

Bioinspired Dynamic Antifouling of Oil-Water Separation Membrane by Bubble-Mediated Shape Morphing

Oil–water separation membranes easily fail to oil foulants with low surface energy and high viscosity, which severely limits these membranes’ applications in treating oily wastewater. Herein, an oil–water separation membrane by bioinspired bubble-mediated antifouling strategy is fabricated via growing hierarchical cobalt phosphide arrays on stainless steel mesh. The as-prepared membrane is superhydrophilic/superaerophobic and electrocatalytic for hydrogen evolution under water, which helps to rapidly generate and release abundant microbubbles surrounding the oil-fouled region on the membrane. These microbubbles can spontaneously coalesce with the oil foulants to increase their buoyancy and warp their interface tension by morphing the oil shape. And this spontaneous coalescence also increases the kinetic energy of oil foulants resulting from the decreased bubbles’ interface energy and potential energy. The synergy of the warped interface tension, increased buoyancy, and kinetic energy drives the efficiently dynamic antifouling of this membrane. This dynamic antifouling even can remove some solid sediment such as oily sand particles that causes more serious fouling of the membrane. Thus, this membrane maintains high flux (>11920 L m⁻² h⁻¹ bar⁻¹) in the long-term separation of oil–water and oil–sand–water emulsions by dynamically recovering the decayed flux on demand, which exhibits great potential in treating industrial oily wastewater.     

A Self-Growth Strategy for Simultaneous Modulation of Interlayer Distance and Lyophilicity of Graphene Layers toward Ultrahigh Potassium Storage Performance

Herein, a simple but effective self-growth strategy to simultaneously modulate the interlayer distance and lyophilicity of graphene layers, which results in ultrahigh potassium-storage performances for carbon materials, is reported. This strategy involves the uniform adsorption of individual metal ions on the oxygen-containing groups on graphene oxide via electrostatic/coordination interactions and in situ self-conversion reaction between the metal ions and the oxygen-containing groups to form lyophilic ultrasmall metal oxide nanoparticles modified/intercalated graphene skeleton (OM-G) with precisely regulated interlayer distance. The synergistic effect of expanded interlayer distance and enhanced lyophilicity is revealed for the first time to significantly reduce the ion diffusion barrier and enhance ion transport kinetics by experimental and theoretical analysis. As a result, such unique OM-G monolith as free-standing anode for potassium-ion battery (PIB) delivered an ultrahigh reversible capability of 496.4 mAh g⁻¹ at 0.1 A g⁻¹, excellent rate capability (306.6 mAh g⁻¹ at 10 A g⁻¹), and remarkable long-term cycling stability (96.3% capacity retention over 2000 cycles at 1 A g⁻¹), which are not only much better than those of previous graphene/carbon materials but also among the best performances for all PIB anodes ever reported. This study provides new fundamental insights for boosting the electrochemical properties of electrode materials.