High Retention Efficiency Research Articles

A Novel Structured Si‐Based Composite with 2D Structured Graphite for High‐Performance Lithium‐Ion Batteries

AbstractSilicon is a promising alternative to graphite anodes for achieving high‐energy‐density in lithium‐ion batteries (LIBs) because of its high theoretical capacity (3579 mAh g−1). However, silicon anode must be developed to address its disadvantages, such as volume expansion and low electronic conductivity. Therefore, the use of silicon as composed with graphite and carbon anode materials is investigated, which requires properties such as a spherical morphology for high density and encapsulation of silicon particles in the composite. Herein, a graphite@silicon@carbon (Gr@Si@C) micro‐sized spherical anode composite is synthesized by mechanofusion process. This composite comprises an outer surface, middle layer, and core pore, which are formed by the capillary force arising from 2D structured graphite and pitch properties. This structure effectively addresses the intrinsic issues associated with Si. Gr@Si@C exhibits a high capacity of 1622 mAh g−1 and capacity retention of 72.2% after 100 cycles, with a high areal capacity 4.2 mAh cm−2. When Gr@Si@C is blended with commercial graphite, the composite exhibits high capacity retention and average Coulombic efficiency after cycling. The Gr@Si@C blended electrode exhibits a high energy density of 820 Wh L−1 with ≈16% metallic Si in the electrode (40 wt.% composite), enabling the realization of practical commercial LIBs.

Biomimetic structural aerogel derived from green tide enteromorpha-prolifera: Multi-sided unidirectional freeze casting and solar-driven viscous oil spill remediation

The development of environmental remediation materials from renewable biowaste, especially for the cleanup of viscous oil spills in an eco-friendly manner, marks a substantial advancement in functional materials. This study proposes a biomass aerogel (M−MCEP) transformed from Enteromorpha prolifera (EP) in green tides for solar-driven recovery of high-viscosity oil spills. Inspired by the lamella-bridge architecture of Thalia dealbata stems, a biomimetic structure with multi-domain, long-range aligned lamella-bridge interconnections is constructed by a multi-sided unidirectional freeze-casting technique. Multi-scale interface optimization between rigid photothermal fillers and soft lamellar layers achieves multiple reinforcements, providing aerogel with a perfect balance of elasticity and strength. The multidomain low tortuosity channels and photothermal effects enhance M−MCEP’s photothermal conversion (95.2 %) and thermal conductivity (0.3517 W/m·K), reducing oil flow resistance and achieving high oil retention efficiency (>92 %). Under 1 sun irradiation, M−MCEP rapidly heats to 67.3 °C, effectively reducing the viscosity of crude oil in situ, with a crude oil adsorption rate of 1843 mL/m2 within 30 s. Moreover, M−MCEP captures emulsified oil in oil-in-water emulsions through high-speed repeated oscillations, achieving a separation efficiency of 96.42–99.21 %. Renewable resources and unique structural designs provided by nature drive the development of advanced biomimetic aerogels for efficiently remedying catastrophic oil spills.

An Ion-Pumping Quasi-Solid Electrolyte Enabled by Electrokinetic Effects for Stable Aqueous Zinc Metal Batteries.

The practical application of aqueous zinc (Zn) metal batteries (ZMBs) is hindered by the complicated hydrogen evolution, passivation reactions, and dendrite growth of Zn metal anodes. Here, an ion-pumping quasi-solid electrolyte (IPQSE) with high Zn2+ transport kinetics enabled by the electrokinetic phenomena to realize high-performance quasi-solid state Zn metal batteries (QSSZMBs) is reported. The IPQSE is prepared through the in situ ring-opening polymerization of tetramethylolmethane-tri-β-aziridinylpropionate in the aqueous electrolyte. The porous polymer framework with high zeta potential provides the IPQSE with an electrokinetic ion-pumping feature enabled by the electrokinetic effects (electro-osmosis and electrokinetic surface conduction), which significantly accelerates the Zn2+ transport, reduces the concentration polarization and overcomes the diffusion-limited current. Moreover, the Zn2+ affinity of the polymer and hydrogen bonding interactions in the IPQSE changes the Zn2+ coordination environment and reduces the amount of free H2O, which lowers the H2O activity and inhibits H2O-induced side reactions. Consequently, the highly reversible and stable Zn metal anodes are achieved. The assembled QSSZMBs based on the IPQSE display excellent cycling stability with high capacity retention and Coulombic efficiency. The high-performance quasi-solid state Zn metal pouch cells are demonstrated, showing great promise for the practical application of the IPQSE.

RESEARCH ON THE FORMULATION OF NANOPARTICLES CONTAINING MANGIFERIN USING SELF-ASSEMBLY METHOD

Background: The use of natural-origin active compounds in disease treatment is currently a prevailing trend. Mangiferin, a major component found in mangoes, is present in relatively high proportions. However, mangiferin's disadvantages include low solubility and poor permeability. There are numerous methods available to improve solubility and permeability, among which selfassembly is noteworthy. Self-assembly involves the combination of certain molecules or macromolecules to form three-dimensional networks or other structures with new characteristics, phospholipids and chitosan are often used as raw materials for the self-assembly process to create nanoparticles. This method offers advantages such as high efficiency, simple implementation, short execution time, high retention efficiency, and increased permeability through biological membranes. Objectives: To develop a formulation and process for producing nano mangiferin using the selfassembly method with phosphatidylcholine and chitosan. Materials and methods: The solubility of mangiferin in high-proof ethanol was investigated, followed by an assessment of the influence of formulation factors and processes on the characteristics of nano-sized mangiferin particles. Results: The average solubility of mangiferin in 96% ethanol was approximately 0.5529±0.0003 mg/mL. The mole ratio of mangiferin to Lipoid S100 was 1:1, and the mass ratio of Lipoid S100 to chitosan was 20:1. A stirring speed of 1.000 revolutions per minute, reflux temperature of 70°C, reflux time of 2 hours. homogenization speed of 1,000 revolutions per minute, and homogenization time of 15 minutes produced the smallest nanoparticles (103.44±0.46 nm), with a low polydispersity index (0.281±0.009≤ 0.3) and zeta potential (31.95±0.08 mV ≥ +30 mV), encapsulation efficiency of 82.42±0.53%; loading capacity of 32.97±0.95%. Conclusions: A successful formulation of nanosized mangiferin particles was achieved using the self-assembly method, resulting in particles that meet the criteria of small size, uniformity, and durability. Moreover, nearly 100% mangiferin release was achieved after 60 minutes, indicating the promising potential for developing highly bioavailable oral formulations.

A Triazine Membrane for Sustainable Acquisition of Au(III) from Wastewater.

The recovery of Au(III) from solution using adsorbents in the form of granules or powders is challenging due to issues such as instability during the recovery process or mass loss caused by small particle size. This study introduces a PEI-TCT/PVDF composite membrane designed to intercept and capture Au(III) in wastewater. Experimental results demonstrated that the PEI-TCT/PVDF membrane exhibits a broad pH range (1-8) and a high retention efficiency for Au(III) of 97.8%, with a maximum adsorption capacity of 294.5 mg/g. The mechanism of Au(III) adsorption on the PEI-TCT/PVDF membrane was mainly through electrostatic adsorption, which caused AuCl4- to aggregate on the surface of the membrane and gradually reduced to Au0 and Au+. Furthermore, the membrane can be entirely regenerated within 20 min and maintains its performance in subsequent adsorption cycles. This study highlights the potential of PEI-TCT/PVDF membranes for the recovery of precious Au(III).

Characterization of Phosphorylated Peptides by Electron-Activated and Ultraviolet Dissociation Mass Spectrometry: A Comparative Study with Collision-Induced Dissociation.

Mass-spectrometry-based methods have made significant progress in the characterization of post-translational modifications (PTMs) in peptides and proteins; however, room remains to improve fragmentation methods. Ideal MS/MS methods are expected to simultaneously provide extensive sequence information and localization of PTM sites and retain labile PTM groups. This collection of criteria is difficult to meet, and the various activation methods available today offer different capabilities. In order to examine the specific case of phosphorylation on peptides, we investigate electron transfer dissociation (ETD), electron-activated dissociation (EAD), and 193 nm ultraviolet photodissociation (UVPD) and compare all three methods with classical collision-induced dissociation (CID). EAD and UVPD show extensive backbone fragmentation, comparable in scope to that of CID. These methods provide diverse backbone fragmentation, producing a/x, b/y, and c/z ions with substantial sequence coverages. EAD displays a high retention efficiency of the phosphate modification, attributed to its electron-mediated fragmentation mechanisms, as observed in ETD. UVPD offers reasonable retention efficiency, also allowing localization of the PTM site. EAD experiments were also performed in an LC-MS/MS workflow by analyzing phosphopeptides spiked in human plasma, and spectra allow accurate identification of the modified sites and discrimination of isomers. Based on the overall performance, EAD and 193 nm UVPD offer alternative options to CID and ETD for phosphoproteomics.

Smart Energy Storage: W18O49 NW/Ti3C2Tx Composite-Enabled All Solid State Flexible Electrochromic Supercapacitors.

Developing a highly efficient electrochromic energy storage device with sufficient color fluctuation and significant electrochemical performance is highly desirable for practical energy-saving applications. Here, to achieve a highly stable material with a large electrochemical storage capacity, a W18O49 NW/Ti3C2Tx composite has been fabricated and deposited on a pre-assembled Ag and W18O49 NW conductive network by Langmuir-Blodgett technique. The resulting hybrid electrode composed of 15 layers of W18O49 NW/Ti3C2Tx composite exhibits an areal capacitance of 125mFcm-2, with a fast and reversible switching response. An optical modulation of 98.2% can be maintained at a current density of 5mAcm-2. Using this electrode, a bifunctional symmetric electrochromic supercapacitor device having an energy density of 10.26µWhcm-2 and a power density of 0.605mWcm-2 is fabricated, with high capacity retention and full columbic efficiency over 4000 charge-discharge cycles. Meanwhile, the device displays remarkable electrochromic characteristics, including fast switching time (5s for coloring and 7s for bleaching), and a significant coloration efficiency of 116cm2C-1 with good optical modulation stability. In addition, the device exhibits significant mechanical flexibility and fast switching while being stable over 100 bending cycles, which is promising for real-world applications.

Development of Cellulose Air Filters for Capturing Fine and Ultrafine Particles through the Valorization of Banana Cultivation Biomass Waste

Outdoor and indoor atmospheric pollution is one of the major problems that humanity continues to face. As a mitigation pathway, numerous technologies have been developed for air purification, including the use of fibrous filters. In this study, the particle capture efficiencies and pressure drops of air filters manufactured with cellulose pulp extracted from banana pseudostems were studied across three particle size ranges (PM10, PM2.5, and PM1). Two pretreatments were applied, alkaline with soda-antraquinone (alkali-treated pulp) and a subsequent bleaching process (bleached pulp), and four manufacturing processes were tested: crushing, freeze-drying, vacuum filtration, and pressing. In addition, a study varying filter grammage (70, 100, and 160 g·m−2) and pressing pressures (2, 4, 6, and 8 t) was also performed. After conducting these particle tests, the filter manufactured with bleached pulp, having a grammage of 160 g·m−2 and pressed at 4 t, was deemed the optimal individual solution. It demonstrated high particle retention efficiencies across all particle size ranges (with values exceeding 80%), a moderate pressure drop below 1000 Pa, and high thermal stability (degradation above 220 °C). However, combining freeze-drying and two-ton pressing processes yielded improved results (83% for the smallest particles and 89% for others) with approximately half the pressure drop. Based on these results, this study stands as a noteworthy contribution to waste valorization and the advancement of environmentally friendly materials for particle air filters. This is achieved through the adoption of simple and cost-effective technology, coupled with the utilization of 100% natural agricultural waste as the primary manufacturing material.

Ultralight crystalline hybrid composite material for highly efficient sequestration of radioiodine

Considering the importance of sustainable nuclear energy, effective management of radioactive nuclear waste, such as sequestration of radioiodine has inflicted a significant research attention in recent years. Despite the fact that materials have been reported for the adsorption of iodine, development of effective adsorbent with significantly improved segregation properties for widespread practical applications still remain exceedingly difficult due to lack of proper design strategies. Herein, utilizing unique hybridization synthetic strategy, a composite crystalline aerogel material has been fabricated by covalent stepping of an amino-functionalized stable cationic discrete metal-organic polyhedra with dual-pore containing imine-functionalized covalent organic framework. The ultralight hybrid composite exhibits large surface area with hierarchical macro-micro porosity and multifunctional binding sites, which collectively interact with iodine. The developed nano-adsorbent demonstrate ultrahigh vapor and aqueous-phase iodine adsorption capacities of 9.98 g.g−1 and 4.74 g.g−1, respectively, in static conditions with fast adsorption kinetics, high retention efficiency, reusability and recovery.

Chemically robust functionalized covalent organic framework for the highly efficient and selective separation of bromine.

Effective sequestration of bromine holds great promise for the chemical industry's safe expansion, environmental preservation, and public health. However, attaining this goal is still challenging due to the serious drawbacks of existing adsorbents such as limited capacity, low retention efficiency, and sluggish uptake kinetics. Herein, we report a strategy-driven systematic study aimed at significantly enhancing multiple host-guest interactions to obtain functionalized covalent-organic frameworks for the efficient sequestration of bromine. Results showed that the presence of specific quantities of selective binding sites of the porous frameworks afford stronger host-guest interactions and therefore higher bromine adsorption capacities. The developed framework exhibits high bromine sorption capacity of up to 5.16 g g-1 in the vapor phase and 8.79 g g-1 in the aqueous phase under static adsorption conditions with fast kinetics, large distribution coefficient (Kd ∼105 mL g-1), high retention efficiency and reusability. Moreover, the adsorbent is able to sequestrate trace bromine (from 13 ppm to below 4 ppm) from aqueous medium with fast adsorption kinetics (86.3% within less than 3 h) and demonstrates the selective extraction of bromine over iodine under both static and dynamic conditions. These results were further utilized to demonstrate recycling-selective and highly efficient bromine capture from a real-water system, exhibiting excellent scalability and affordability, as exemplified using COF membranes in a continuous flow-through process.

Mineral formation explains the high retention efficiency of dissolved reactive phosphorus in a residential stormwater pond

Stormwater ponds (SWPs) alter the export of the macronutrient phosphorus (P) from urban landscapes, hence impacting the trophic state and water quality of downstream aquatic environments.

Nickel-Doped Tungsten Disulfide for Energy Storage Applications

Nickel-doped hexagonal pyramid-like tungsten disulfide (WS2) has been synthesized via a simple hydrothermal synthesis method and offers great promise for use in electrochemical energy storage devices such as supercapacitors. The nickel concentration of 3, 4.5, and 6 at. % was added to WS2. Three-electrode and two-electrode configurations are used to test the electrochemical performances of the materials as prepared. The nickel doping of 4.5 at. % exhibits a high specific capacitance of 144 F g−1 at a current density of 1 A g−1 with an energy density of 13.3 Wh kg−1 and power density of 802 W kg−1 for the symmetric supercapacitor device. Increased electrochemically active surface area and decreased impedance are attributed to the improved supercapacitive performances. Finally, high specific power retention (92.1%) and Coulomb efficiency (86.0%) were demonstrated after 3,000 cycles. These results demonstrate that the synthesized nickel-doped WS2 can be used for high-performance supercapacitor flexible electrodes.

Self-Standing Single-Ion Borate Salt-Based Polymer Electrolyte for Lithium Metal Batteries.

Polymer electrolytes (PEs) with excellent flexibility and superior compatibility toward lithium (Li) metal anodes have been deemed as one of the most promising alternatives to liquid electrolytes. However, conventional lithium bis(trifluoromethanesulfonyl)imide (LiTFSI)-based dual-ion PEs suffer from a low Li ion transference number and notorious Li dendrite growth. Here, a single-ion conducting polyborate salt without any fluorinated groups, polymeric lithium dihydroxyterephthalic acid borate (PLDPB), is presented for addressing the issues of Li metal batteries. Owing to a nearly immovable bulky anion and the presence of a rigid benzene structure, the PLDPB@poly(ethylene oxide) (PEO) PE exhibits an ultrahigh Li ion transference number (0.94) and excellent mechanical strength, which could significantly restrict the growth of Li dendrites. Postmortem analysis reveals that a fluorine-free solid electrolyte interphase (SEI) enriched with B-O and benzene-containing species is formed on the surface of the Li metal anode, thereby facilitating elimination of excessive parasitic reactions and simultaneously suppressing the formation of Li dendrites. Consequently, the LiFePO4/Li cells with PLDPB@PEO PEs show an improved long-term cycling performance and high capacity retention (90.0%) and Coulombic efficiency (99.9%) after 500 cycles. This work may inspire new ideas to boost the development of single-ion conducting salts for dendrite-free Li metal batteries.

Degradation Control of All-Solid-State Na Batteries by Inorganic Oxide Coated Positive Electrode Active Material

All-solid-state Na batteries (ASSBs) are attracted attention owing to their high safety and resource properties for next-generation batteries. Na has the advantage of abundant resources compared to Li. In addition, polymer electrolyte is expected to improve the safety of the battery by suppressing the risk of ignition with liquid leakage. In general, the degradation of batteries using polymer electrolyte mainly occurs at the positive electrode (PE)/electrolyte interface during charge process. In case of batteries using active material having layered structures such as NaCoO2 and polyether electrolyte, the degradation of CoO2 structure and decomposition of polyether during the deintercalation of Na+ in the active material. These PE / electrolyte interface degradations contribute to increasing resistance of the battery. To suppress interfacial degradation, inorganic oxides coating for active materials were reported in the Li-based battery[1]. In this study, Na3PO4 or Na3Zr2Si2PO12 (NZSP) coated PEs were applied for ASSBs to suppress degradation. The degradation behavior of ASSBs was investigated by charge / discharge test and XRD analysis using extracted PE sheet from cell. Furthermore, Raman spectroscopy was applied on the cell before and after charge / discharge test to investigate structural changes in active material and polymer electrolyte.NaTFSA as Na salt, P(EO/PO) as polyether-based macromonomer, and DMPA as photoinitiator were mixed into Ar-filled glovebox. NaTFSA was added by ratio of [Na]/[O]=0.1 per molar of oxygen units of P(EO/PO). Polymer electrolyte films were prepared by UV irradiation for obtained homogeneous solution. NaCoO2 (NCO) as active material, acetylene black (AB) as conductive additive, and P(EO/MEEGE)-NaTFSA as binder were mixed by 82:5:13 weight ratio. The Na3PO4 and NZSP as inorganic oxides were added 5 wt.% and 10 wt.% for NCO, respectively. Applied slurry (thick. 50 µm) onto Al foil was cut to Φ16 mm after vacuum dry. The PE sheet, Na metal negative electrode, and polymer electrolyte were assembled into coin-cell to fabricate ASSBs. The charge / discharge tests for more than 10 cycles were performed at 333K after heat-treated at 363K for 48h. After charge / discharge test, XRD analysis was applied to extracted PE sheet from the cell under a low dew point for structural evaluation. Moreover, PE, polymer electrolyte, and Na metal were initially cut to 9 mm × 9 mm and introduced into the Raman cell with observation window to observe the cross-section of the cell. Raman spectroscopy was performed to the cross-section of the cell before and after charge / discharge test in order to investigate the degradation behavior of PE and polymer electrolyte.Fig. 1 shows charge / discharge profiles of non-coated and 10 wt.% NZSP coated PE in the cells. The 1st discharge capacity was 36 mAhg-1 in the non-coated system, and was also the insufficient capacity of about 30% from the theoretical capacity (ca. 118 mAhg-1) of NCO. In contrast, the NZSP-coated PE improved the 1st discharge capacity to 60 mAhg-1, and clear plateau was observed owing to their crystal structure change of NCO. These results suggest that inorganic oxide served as sufficient ionic conduction path between PE and electrolyte, reducing the interfacial resistance. Fig. 2 shows the cycle number dependencies of capacity and Coulombic efficiency. ASSB with inorganic oxides coated PE showed high discharge capacity retention and Coulombic efficiency in comparison with non-coated system. These results are suggesting that inorganic oxides coating active material surface suppress increase of interfacial resistance and degradation of the PE/electrolyte by prevent the formation of side products such as Co3O4 [2]. NZSP has higher Na ionic conductivity than Na3PO4, and can cover more apparent area of NCO surface than Na3PO4 because of their smaller particle size. Therefore, from comparing Na3PO4 and NZSP coating, NZSP more contributes to suppressing degradation of the cell. Fig. 3 shows the results of XRD analysis for PEs after charge / discharge test. Peaks attributed to NCO were confirmed in the PE before degradation, however, peak intensity decreased after degradation, especially for (003) and (006) of NCO. The peak derived from Co3O4 was confirmed only after degradation. These results suggest that structural degradation of NCO occurs during charging and discharging of the cell, resulting in the formation of Co3O4. In addition, the inorganic oxide coating should be contributed to maintaining the structure of the active material. In this presentation, the analysis results of structural changes of PE and electrolyte before and after charge / discharge test by Raman spectroscopic measurement will be also reported.

Multifunctional-regions integrated with Mn-Co-Ni ternary hydroxides as self-assembled electrodes for high-performance hybrid supercapacitors

High-performance supercapacitors require elaborate design for electroactive materials with hierarchical structure and multiple components. In the present work, hierarchical nanoarrays composed of MnCoNi LDH@CoNi LDH (MCNL@CNL) with enoki-mushroom-like structure were constructed by integrating the structural regions with complementary functions. The self-assembled electrodes were fabricated upon MCNL@CNL with MnCo LDH@ZIF-67 as precursor and nickel foam as supporter, which achieved a specific capacitance of 2126.7 F/g at 0.5 A/g. The assembled hybrid supercapacitor exhibited the maximum energy density and power density of 51.4 Wh/kg and 7500 W/kg within the voltage range of 0–1.5 V, respectively, and it provided cycling stability with high capacitance retention (104.1%) and Coulombic efficiency (101.1%) after 10,000 cycles. Based on the characterizations results, MCNL@CNL electrode endowed with fast mass transfer, high conductivity and rich electroactive sites was produced, and its induced synergy effect facilitated charge transfer and promoted specific capacitance. Moreover, the hierarchical structure and rough surface of the fabricated MCNL@CNL accelerated the ions/electrons diffusion, and the cross-growing nanosheets on the surface enhanced the affinity. This work provides a novel approach to designing and fabricating self-assembled electrodes with high-performance and lifetime for supercapacitors.

Evaluation of various factors influencing dynamic membrane formation and performance using metal oxide adsorbent

A dynamic membrane (DM) comprises a layer of particles deposited onto a conventional membrane, which minimizes fouling of the primary membrane to enhance permeate fluxes. Because DMs are involved in adsorption, the size and material of the adsorbent significantly affect DM performance. However, the comprehensive effects of these factors on DMs remain unclear. Herein, the factors influencing DM morphology and performance were investigated by varying the size of two different DM adsorbent materials: heated aluminum oxide particles (HAOPs) and heated iron oxide particles (HIOPs), deposited on polymeric and ceramic (CE) membranes. The density of the dynamic layer increased as the adsorbent particle size decreased. All DMs exhibited approximately 30 % improved flux and higher humic acid (HA) removal efficiencies (HAOP-DM:90 %, HIOP-DM:82 %) than the virgin membranes. Adsorbent size significantly affected DM performance; a five-fold size reduction resulted in an approximately 25 % increase in HA removal. A membrane resistance model was employed to quantitatively analyze the DM performance. HIOP-DM exhibited 80 %–90 % reversible fouling, whereas HAOP-CE displayed 70 %–80 % irreversible fouling. Because reversible fouling was the dominant mechanism of HIOPs, the DMs were reused after chemical treatment. However, HAOP DMs required replacement, despite their high water flux retention and HA removal efficiency.

Heterojunction assembled CoO/Ni(OH)2/Cu(OH)2 for effective photocatalytic degradation and supercapattery applications.

Mixed multimetallic-based nanocomposites have been considered a promising functional material giving a new dimension to environmental remediation and energy storage applications. On this concept, a hybrid ternary CoO/Ni(OH)2/Cu(OH)2 (CNC) composite showing sea-urchin-like morphology was synthesized via one-pot hydrothermal approach, and its photocatalytic and electrochemical performances were investigated. The photocatalytic performance was explored using Congo red (CR) as a dye pollutant under visible light illumination. The presence of mixed phases of ternary metal ions could minimize the recombination efficacy of photogenerated charge carriers on the basis of the heterojunction mechanism, resulting in 90% degradation of CR dye (40mg L-1). The effect of scavengers coupled with electrochemical experiments revealed O2-. radical as the predominating species responsible for the degradation of CR. From the electrochemical analysis of CNC, the well-distinguished redox peaks indicated the redox-type nature with a specific capacity of 405 C g-1. For practical applications, an supercapattery (CNC( +)|KOH|AC( -)) was assembled furnishing an energy density of 42 W h kg-1 at a power density of 5160 W kg-1 at 5 A g-1 along with a high capacity retention and coulombic efficiency of 98.83% over 5000 cycles.

Biomass-derived porous carbon aerogels for effective solar thermal energy storage and atmospheric water harvesting

Solar-powered hydrated salt-based phase change materials have great potential in the field of solar building energy efficiency. However, hydrated salts suffer from leakage, subcooling and phase separation in practical applications. To address these problems, this study proposes a solution to encapsulate hydrated salt with biomass-derived carbon aerogel as a carrier, which can effectively mitigate the leakage, subcooling, and phase separation problems of hydrated salt without the need of additional modifiers. The composite phase change material exhibited high phase change enthalpy retention (92%), negligible supercooling (0.4 °C), and excellent photothermal conversion efficiency (91.5%). In addition, thanks to the rich porosity and superhydrophilicity of the carbon aerogel, a composite hygroscopic agent combined with lithium chloride was prepared for high-performance atmospheric water harvesting. The composite hygroscopic material has a moisture adsorption capacity of 2.1 g g−1 at 90% RH and can desorb more than 92.3% of the moisture by solar energy drive. The performance was stable after several adsorption-desorption cycles. The multifunctional composites based on biomass-derived carbon aerogels have excellent performance in solar thermal storage and atmospheric water harvesting, providing a new perspective on solar thermal utilization.

High-performance chrysanthemum flower-like structure of Ni doped ZnO nanoflowers for pseudo-supercapacitors

In this study, the chrysanthemum-flower-like structure of Ni-doped ZnO nanoflowers pseudo-capacitance behaviour was synthesized by a conventional hydrothermal method. The X-ray diffraction (XRD) results showed that the prepared materials had formed ZnO and Ni-doped ZnO nanopowder in their hexagonal wurtzite structure. The morphologies of the Ni-doped ZnO have a chrysanthemum-flower-like structure, which was confirmed by SEM and HR-TEM. Galvanostatic charge-discharge (GCD), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS) techniques were used to investigate the pseudo-capacitance behaviour of Ni-doped ZnO. The Ni-doped ZnO nanoflower-modified electrode achieved a maximum specific capacitance value of 1090 F/g at 0.25 A/g, and 3 M KOH was used as the electrolyte. Eight thousand cycles of testing revealed that the Ni-doped ZnO nanoflowers electrode was very stable, far outperforming the stability of undoped ZnO nanoflowers modified electrodes. The fabricated Ni-doped ZnO nanoflower electrode has high capacitance retention and high columbic efficiencies of 101 % and 89 %, respectively. The prepared Ni-doped ZnO nanoflowers are a very effective electrode material and are considerably better suited for supercapacitor applications.

Ambient plasma treated tungsten disulfide for electrochemical energy applications

Tungsten disulfide (WS2) is modified, by using ambient solution plasma, for electrochemical energy applications which are hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and flexible supercapacitor applications. Herein, the effect of time-dependent plasma treatment on WS2 is investigated, resulting that the optimum time (60 min) shows the best performances of low overpotential of −0.19 V at −10 mA cm−2 and 0.21 V at 10 mA cm−2 with the corresponding Tafel slopes of 113 mV dec−1 and 124 mV dec−1 for HER and OER, respectively. In addition, a high specific capacitance of 157.5 F g−1 at 1 A g−1 with an energy density of 14 Wh kg−1 and power density of 400 W kg−1 for the flexible supercapacitor is obtained. Reliable flexibility with high specific capacitance retention (94.0%) and coulombic efficiency (89.5%) after 5000 cycles are also demonstrated. The increased electrochemically active surface area, lower impedance, and the phase transition from 2H to 1T, compared to the precursor WS2, by the ambient plasma are ascribed to the better HER, OER, and supercapacitor performance.