Nanoporous Carbon Materials Derived from Zanthoxylum Bungeanum Peel and Seed for Electrochemical Supercapacitors.

In order to prepare biomass-derived carbon materials with high specific capacitance at a low activation temperature (≤700 °C), nanoporous carbon materials were prepared from zanthoxylum bungeanum peels and seeds via the pyrolysis and KOH-activation processes. The results show that the optimal activation temperatures are 700 °C and 600 °C for peels and seeds. Benefiting from the hierarchical pore structure (micropores, mesopores, and macropores), the abundant heteroatoms (N, S, and O) containing functional groups, and plentiful electrochemical active sites, the PAC-700 and SAC-600 derive the large capacities of ~211.0 and ~219.7 F g-1 at 1.0 A g-1 in 6 M KOH within the three-electrode configuration. Furthermore, the symmetrical supercapacitors display a high energy density of 22.9 and 22.4 Wh kg-1 at 7500 W kg-1 assembled with PAC-700 and SAC-600, along with exceptional capacitance retention of 99.1% and 93.4% over 10,000 cycles at 1.0 A g-1. More significantly, the contribution here will stimulate the extensive development of low-temperature activation processes and nanoporous carbon materials for electrochemical energy storage and beyond.

Selenium-Doped Sulfurized Polyacrylonitrile Hybrid Cathodes with Ultrahigh Sulfur Content for High-Performance Solid-State Lithium Sulfur Batteries.

The solid-state lithium sulfur battery (SSLSB) is an attractive next-generation energy storage system by reason of its remarkably high energy density and safety. However, the SSLSB still faces critical challenges, such as sluggish reaction kinetics, mismatched interface, and undesirable reversible capacity. Herein, a high-performance SSLSB is reported using sulfurized polyacrylonitrile with rich selenium-doped sulfur (Se/S-S@pPAN) as a cathode and poly(ethylene oxide)/Li7La3Zr1.4Ta0.6O12 (PEO-LLZTO) as an electrolyte. The sulfur content of the cathode up to 60.9 wt % can be achieved by dispersing selenium sulfide (SeSx) species in the sulfurized polyacrylonitrile (S@pPAN) skeleton at a molecular level. Selenium as a eutectic accelerator can be uniformly distributed in the composite through the Se-S bond and can accelerate the reaction kinetics. The PEO-LLZTO hybrid solid-state electrolyte (SSE) displays an attractive electrochemical performance and provides an intimate contact with electrodes. At 60 °C, Se/S-S@pPAN delivers an impressive discharge capacity of 1042 mAh g-1 at 0.1C and 445 mAh g-1 at 1C. Additionally, the LiFePO4 cathodes combined with PEO-LLZTO deliver a high reversible capacity (158.9 mAh g-1, 1C) and an ultralong lifespan (a capacity retention of 80%, 1000 cycles) at 1C. The synergetic design of the high-performance sulfur cathode and the organic/inorganic hybrid electrolyte is crucial for enabling the high-performance SSLSB.

Light Enables the Cathodic Interface Reaction Reversibility in Solid-State Lithium-Oxygen Batteries.

Limited triple-phase boundaries arising from the accumulation of solid discharge product(s) in solid-state cathodes (SSCs) pose a challenge to high-property solid-state lithium-oxygen batteries (SSLOBs). Light-assisted SSLOBs have been gradually explored as an ingenious system; however, the fundamental mechanisms of the SSCs interface behavior remain unclear. Here, we discovered that light assistance can enhance the fast inner-sphere charge transfer in SSCs and regulate the discharge products with spherical particles generated via the surface growth model. Moreover, the high photoelectron excitation and transportation capabilities of SSCs can retard cathodic catalytic decay by avoiding structural degradation of the cathode with a reduced charge voltage. The light-induced SSLOBs exhibited excellent stability (170 cycles) with a low discharge-charge polarization overpotential (0.27 V). Furthermore, transparent SSLOBs with exceptional flexibility, mechanical stability, and multiform shapes were fabricated for theory-to-practical applications in sunlight-induced batteries. Our study opens new opportunities for the introduction of solar energy into energy storage systems.

Low-strain and ultra-long cycle stability large-diameter soft carbon microsphere potassium ion anode.

Potassium-ion batteries (PIBs) with high potassium abundance, low redox potential of K/K+ and similar energy storage mechanism to lithium-ion batteries are potential candidates for large-scale energy storage in the future. However, due to the large size of K+ (1.38 Å), PIBs exhibit poor kinetics in existing commercial graphite anode materials system. Additionally, they can degrade the material structure and induce significant volume effects, leading to material fragmentation and pulverization in the process of long cycling. It is not straightforward to achieve compatibility with existing potassium anode systems, which forces us to develop new high-performance, low-strain anode materials with outstanding structural stability. Hence, nitrogen doping low-strain and large diameter soft carbon microspheres (NDCS) anodes were successfully developed to meet the demands of high-performance PIBs. Due to its large diameter and low strain characteristics, the Coulomb efficiency is as high as 98.7 %, and the capacity retention is close to 70 % after 4000 cycles at a current density of 1 A/g. Furthermore, we employed advanced computed tomography (CT) techniques to enhance the comprehension of electrochemically driven reactions from the surface to the bulk. This work provides a promising and viable technical solution for exploring PIBs anode materials with low strain and long cycling capabilities to meet the requirements of various application scenarios.

Insights into Electrode Architectures and Lithium-Ion Transport in Polycrystalline V2 O5 Cathodes of Solid-State Batteries.

Polymer-based solid-state batteries (SSBs) have received increasing attentions due to the absence of interfacial problems in sulfide/oxide-type SSBs, but the lower oxidation potential of polymer-based electrolytes greatly limits the application of conventional high-voltage cathode such as LiNix Coy Mnz O2 (NCM) and lithium-rich NCM. Herein, this study reports on a lithium-free V2 O5 cathode that enables the applications of polymer-based solid-state electrolyte (SSE) with high energy density due to the microstructured transport channels and suitable operational voltage. Using a synergistic combination of structural inspection and non-destructive X-ray computed tomography (X-CT), it interprets the chemo-mechanical behavior that determines the electrochemical performance of the V2 O5 cathode. Through detailed kinetic analyses such as differential capacity and galvanostatic intermittent titration technique (GITT), it is elucidated that the hierarchical V2 O5 constructed through microstructural engineering exhibits smaller electrochemical polarization and faster Li-ion diffusion rates in polymer-based SSBs than those in the liquid lithium batteries (LLBs). By the hierarchical ion transport channels created by the nanoparticles against each other, superior cycling stability (≈91.7% capacity retention after 100 cycles at 1 C) is achieved at 60 °C in polyoxyethylene (PEO)-based SSBs. The results highlight the crucial role of microstructure engineering in designing Li-free cathodes for polymer-based SSBs.

Technologies for pollutant removal and resource recovery from blackwater: a review.

Blackwater (BW), consisting of feces, urine, flushing water and toilet paper, makes up an important portion of domestic wastewater. The improper disposal of BW may lead to environmental pollution and disease transmission, threatening the sustainable development of the world. Rich in nutrients and organic matter, BW could be treated for resource recovery and reuse through various approaches. Aimed at providing guidance for the future development of BW treatment and resource recovery, this paper presented a literature review of BWs produced in different countries and types of toilets, including their physiochemical characteristics, and current treatment and resource recovery strategies. The degradation and utilization of carbon (C), nitrogen (N) and phosphorus (P) within BW are underlined. The performance of different systems was classified and summarized. Among all the treating systems, biological and ecological systems have been long and widely applied for BW treatment, showing their universality and operability in nutrients and energy recovery, but they are either slow or ineffective in removal of some refractory pollutants. Novel processes, especially advanced oxidation processes (AOPs), are becoming increasingly extensively studied in BW treatment because of their high efficiency, especially for the removal of micropollutants and pathogens. This review could serve as an instructive guidance for the design and optimization of BW treatment technologies, aiming to help in the fulfilment of sustainable human excreta management.

Correction: Membrane technologies in toilet urine treatment for toilet urine resource utilization: a review.

[This corrects the article DOI: 10.1039/D1RA05816A.].

New insight in algal cell adhesion and cake layer evolution in algal-related membrane processes: Size-fractioned particles, initial foulant seeds and EDEM simulation.

A clear understanding of algal cell adhesion and cake layer evolution in algal-related membrane processes (ARMPs) is urgently required to mitigate the membrane fouling. In this study, the effect of microparticles (10 µm-30 µm), subvisible particles (0.45 µm-10 µm), and ultrafine particles (50 kDa-0.45 µm) on the membrane fouling were explored based on the filtration performance through Hermia models, thermodynamic analysis, and simulation of extended discrete element method (EDEM). The results illustrated that microparticles played an important role in algal cell aggregation and the formation of initial clusters. Intermediate blocking fouling occurred when filtrating the subvisible particle, which facilitated internal adhesion and enhanced biofilm formation. In addition, the interfacial attractive force for the initial algal adhesion was obviously increased when the membrane surfaces were in high concentration of protein and polysaccharide. Moreover, the EDEM simulation demonstrated that subsequent particles, particularly the particles with small sizes, preferred to occupy the spaces among the previously deposited particles. This study provided new insights into the contributions of size-fractioned particles to initial fouling and their influence on the successive adhesion of other contaminants.

2D Zinc-Based Metal-Organic Complexes Derived N-Doped Porous Carbon Nanosheets as Durable Air Cathode for Rechargeable Zn-Air Batteries.

The defect and N-doping engineering are critical to developing the highly efficient metal-free electrocatalysts for oxygen reduction reaction (ORR), mainly because they can efficiently regulate the geometric/electronic structures and sur-/interface properties of the carbon matrix. Herein, we provide a facile and scalable strategy for the large-scale synthesis of N-doped porous carbon nanosheets (NPCNs) with hierarchical pore structure, only involving solvothermal and pyrolysis processes. Additionally, the turnover frequency of ORR (TOFORR) was calculated by taking into account the electron-transfer number (n). Benefiting from the trimodal pore structures, high specific surface area, a higher pore volume, high-ratio mesopores, massive vacancies/long-range structural defects, and high-content pyridinic-N (~2.1%), the NPCNs-1000 shows an excellent ORR activity (1600 rpm, js = ~5.99 mA cm-2), a selectivity to four-electron ORR (~100%) and a superior stability in both the three-electrode tests (CP test for 7500 s at 0.8 V, Δjs = ~0.58 mA cm-2) and Zn-Air battery (a negligible loss of 0.08 V within 265 h). Besides, the experimental results indicate that the enhancement of ORR activity mainly originates from the defects and pyridinic-N. More significantly, this work is expected to realize green and efficient energy storage and conversion along with the carbon peaking and carbon neutrality goals.

Controllable and Homogeneous Lithium Electrodeposition via Lithiophilic Anchor Points.

Uncontrollable growth of lithium (Li) dendrites and low Coulombic efficiency induce security hazards and a short cycling lifespan of Li metal batteries. In this study, well-aligned ZnO nanorods on a periodic three-dimensional (3D) copper mesh (CM) are modified as lithiophilic anchor points to regulate the electrodeposition behavior of Li metal anodes. The in situ generated LiZn/Li2O arrays can efficiently guide the homogeneous Li electrodeposition along the nanorods. The porous structure of CM provides void space for the well-controlled lateral growth of Li starting from nanorod arrays. Moreover, the high surface area generated by both CM and the ZnO nanorods favors the charge transfer with low local current densities along the anode. Compared with bare Li anodes, Li-ZnO@CM anodes exhibited prolonged cycling stability for symmetric cells and superior capacity retention within Li/LiFePO4 full cells, demonstrating the effective design principles of ZnO@CM for stabilizing Li metal batteries.

Hierarchical NiMn/NiMn-LDH/ppy-C induced by a novel phase-transformation activation process for long-life supercapacitor.

For micron-sized nickel-based hydroxides sheets, the reaction and migration of anions/water molecules in the inner region tends to lag behind those along the edge, which can cause structure mismatch and capacity degradation during cycles. Nanosizing and structure design is a feasible solution to shorten the ion/electron path and improve the reaction homogeneity. Herein, this study reports a novel three-stage strategy (self-assembly of NiMn-LDH/ppy-C - reduction to NiMn/ppy-C - in situ phase transformation into NiMn/NiMn-LDH/ppy-C) to reduce the sheet size of NiMn-LDH to nanometer. Triggered by electrochemical activation, NiMn-LDH nanosheets can hereby easily and orderly grow on the exposed active (111) crystal plane of Ni to establish NiMn-LDH/NiMn heterostructure around ppy-C. Importantly, nanosizing and hierarchical structure play a synergistic role to maintain structural integrity and to promote the electron/mass transfer kinetics. The NiMn/NiMn-LDH/ppy-C composite delivers superior cycling stability with almost no decay of capacity retention after 40,000 cycles at 5 A g-1. Our hierarchical morphology modulation provides an ingenious, efficient way to boost the performance of Ni-based layered hydroxide materials.

A promising microalgal wastewater cyclic cultivation technology: Dynamic simulations, economic viability, and environmental suitability.

The microalgal wastewater cyclic cultivation technology (AWC2T) proposed in this study helps address the challenges surrounding water scarcity and ecological sustainability in a clean, resource-efficient, and affordable manner. A novel microalgae growth model (AGM) elucidating the growth mechanisms of microalgae in the AWC2T system was established for dynamic simulations and design optimization. The recycled wastewater accelerated the growth rate of microalgae, and increased biomass and lipids content by 11% and 37.65%, respectively, after 8 batches of cultivation. The accumulated soluble algae products (SAPs) enhanced microalgae growth by providing nutrients and regulating metabolism. In addition, scenario simulations illustrated the excellent long-term performance of the AWC2T system. 100% recycling of microalgal wastewater could save 0.3% N and 54.36% P. The techno-economic analysis (TEA) and life cycle assessment (LCA) explored how economic and sustainability principles can be embedded into the life cycle of microalgae production. The AWC2T led to outcomes vastly superior to non-cyclic technology by enabling the high-level recovery of resources, providing substantial benefits, enhancing contingency and risk resistance, and offsetting a host of unintended environmental effects.

Hierarchical Stratiform of a Fluorine-Doped NiO Prism as an Enhanced Anode for Lithium-Ion Storage.

Doping is regarded as a prominent strategy to optimize the crystal structure and composition of battery materials to withstand the anisotropic expansion induced by the repeated insertion and extraction of guest ions. The well-known knowledge and experience obtained from doping engineering predominate in cathode materials but have not been fully explored for anodes yet. Here, we propose the practical doping of fluorine ions into the host lattice of nickel oxide to unveil the correlation between the crystal structure and electrochemical properties. Multiple ion transmission pathways are created by the orderly two-dimensional nanosheets, and thus the stress/strain can be significantly relieved with trace fluorine doping, ensuring the mechanical integrity of the active particle and superior electrochemical properties. Density functional theory calculations manifest that the F doping in NiO could improve crystal structural stability, modulate the charge distribution, and enhance the conductivity, which promotes the performance of lithium-ion storage.

Understanding the Effect of Second Metal on CoM (M = Ni, Cu, Zn) Metal-Organic Frameworks for Electrocatalytic Oxygen Evolution Reaction.

Co-based bimetallic metal-organic frameworks (MOFs) have emerged as a kind of promising electrocatalyst for oxygen evolution reaction (OER). However, most of present works for Co-based bimetallic MOFs are still in try-and-wrong stage, while the OER performance trend and the underlying structure-function relationship remain unclear. To address this challenge, Co-based MOFs on carbon cloth (CC) (CoM MOFs/CC, M = Zn, Ni, and Cu) are prepared through a room-temperature method, and their structure and OER performance are compared systematically. Based on the results of overpotential and Tafel slope, the order of OER activity is ordered in the decreasing sequence: CoZn MOF > CoNi MOF > CoCu MOF > Co MOF. Spectroscopic studies clearly show that the better OER performance of CoM MOFs results from the higher oxidation state of Co, which is related to the choice of second metal. Theoretical calculations indicate that CoZn MOFs possess strengthened adsorption for O-containing intermediate, and lower energy barrier towards OER. This study figures out the effect of second metal on the OER performance of Co-based bimetallic MOFs and suggests that tuning the electronic structure of the metal site can be an effective strategy for other MOFs-based OER catalysts.

Mechanistic Insights into the Structural Modulation of Transition Metal Selenides to Boost Potassium Ion Storage Stability.

Atomic-level structure engineering is an effective strategy to reduce mechanical degradation and boost ion transport kinetics for battery anodes. To address the electrode failure induced by large ionic radius of K+ ions, herein we synthesized Mn-doped ZnSe with modulated electronic structure for potassium ion batteries (PIBs). State-of-the-art analytical techniques and theoretical calculations were conducted to probe crystalline structure changes, ion/electron migration pathways, and micromechanical stresses evolution mechanisms. We demonstrate that the heterogeneous adjustment of the electronic structure can relieve the potassiumization-induced internal strain and improve the structural stability of battery anodes. Our work highlights the importance of the correlation between doping chemistry and mechanical stability, inspiring a pathway of structural engineering strategy toward a highly stable PIBs.

Gas-Flow-Assisted Wrinkle-Free Transfer of a Centimeter-Scale Ultrathin Alumina Membrane onto Arbitrary Substrates.

The transfer of an ultrathin membrane onto arbitrary substrates is important in different practical fields. Conventional wet-transfer methods inevitably induce wrinkle defects as a result of the large contact angle of the trapped droplet between the membrane and the substrate. Here, we demonstrate a gas flow-assisted method (GFAM) to transfer centimeter (cm)-scale ultrathin membranes onto arbitrary substrates (including a curved substrate) without wrinkles. GFAM makes use of contact angle hysteresis to bulge the trapped droplet between the substrate and the ultrathin membrane and simultaneously stretch the ultrathin membrane during rapid dewetting driven by gas flow. Moreover, GFAM can be easily fulfilled by using compressed air for seconds. Compared with conventional hydrophilic treatments or organic liquid wetting, this method has no durability concern and does not change the surface nature of substrates. Taking a widely used ultrathin anodic aluminum oxide (AAO) membrane as an example, we successfully demonstrate the application of a large-area wrinkle-free ultrathin AAO membrane to defect-free ordered nanostructure array fabrication and investigate the micro-scale details of macro-scale wrinkles generated by the conventional ways. In addition, its corresponding superiority over the defective counterpart is further studied in optical sensing. This method is highly valuable for promoting the simplicity of large-area ultrathin membrane transfer in practice.

Laser-based precision alignment for multiple span rotary shafts.

By converting the alignment issue of multiple span rotary shafts into a non-connected shaftalignment issue, we present a precision alignment strategy for multiple span shafts, and a laser-based method for measuring misalignment of non-connected shafts is proposed. The quadrant photodiode detector was calibrated at different rotation angles to obtain the sensitivity coefficient. According to the calibration results, the experiment scheme of the method was optimized. Then measurement experiments were carried out and the error source, the measurement uncertainty of the results were analyzed. Finally, the misalignment was also measured by a coordinate measuring machine, and the comparison results show that the relative error of the two methods is less than 5%. Therefore, the proposed method can be applied to align multiple span shafts accurately. Furthermore, this method can also be used for non-connected shaft position determinations such as wheel alignment inspections, alignment of machine spindle and center shaft, and others.

Membrane technologies in toilet urine treatment for toilet urine resource utilization: a review.

Membrane technologies have broad potential in methods for separating, collecting, storing, and utilizing urine collected from toilets. Recovering urine from toilets for resource utilization instead of treating it in a sewage treatment plant not only reduces extra energy consumption for the degradation of N and P but also saves energy in chemical fertilizer production, which will contribute to carbon emission reduction of 12.19-17.82 kg kgN -1 in terms of N alone. Due to its high efficiency in terms of volume reduction, water recycling, nutrient recovery, and pollutant removal, membrane technology is a promising technology for resource utilization from urine collected from toilets. In this review, we divide membrane technologies for resource utilization from urine collected from toilets into four categories based on the driving force: external pressure-driven membrane technology, vapor pressure-driven membrane technology, chemical potential-driven membrane technology, and electric field-driven membrane technology. These technologies influence factors such as: recovery targets and mechanisms, reaction condition optimization, and process efficiency, and these are all discussed in this review. Finally, a toilet with source-separation is suggested. In the future, membrane technology research should focus on the practical application of source-separation toilets, membrane fouling prevention, and energy consumption evaluation. This review may provide theoretical support for the resource utilization of urine collected from toilets that is based on membrane technology.

Insights into interfacial effect and local lithium-ion transport in polycrystalline cathodes of solid-state batteries.

Interfacial issues commonly exist in solid-state batteries, and the microstructural complexity combines with the chemical heterogeneity to govern the local interfacial chemistry. The conventional wisdom suggests that "point-to-point" ion diffusion at the interface determines the ion transport kinetics. Here, we show that solid-solid ion transport kinetics are not only impacted by the physical interfacial contact but are also closely associated with the interior local environments within polycrystalline particles. In spite of the initial discrete interfacial contact, solid-state batteries may still display homogeneous lithium-ion transportation owing to the chemical potential force to achieve an ionic-electronic equilibrium. Nevertheless, once the interior local environment within secondary particle is disrupted upon cycling, it triggers charge distribution from homogeneity to heterogeneity and leads to fast capacity fading. Our work highlights the importance of interior local environment within polycrystalline particles for electrochemical reactions in solid-state batteries and provides crucial insights into underlying mechanism in interfacial transport.

DFT and experimental study of nano red phosphorus anchoring on sulfurized polyacrylonitrile for lithium-ion batteries.

Sulfur atoms can reconstruct the configuration of PAN, which makes the electron transfer more convenient and reduces the energy barriers during Li ion diffusion. The sulfurized polyacrylonitrile plays a crucial role in anchoring the P4 molecule and electron transport simultaneously. Uniform RP nanoparticles (∼200 nm) are obtained using a simple liquid phase method. SPAN-RP shows an initial reversible capacity of 1214 mA h g-1 at 0.2C and retains a capacity of 860 mA h g-1 with a high coulombic efficiency of 99.6% after 200 cycles.