Synergistic extraction and separation of valuable elements from high-alumina fly ash with carbochlorination method

A novel process was proposed for synergistic extraction and separation of valuable elements from high-alumina fly ash.A thermodynamic analysis revealed that to achieve effective carbochlorination,it is crucial to conduct carbochlorination of the fly ash within the temperature range from 700 to 1000℃.The experimental results demonstrated that under the optimal conditions,the carbochlorination efficiency for Al,Si,Ca,Ti,and Mg exceeded 81.18%,67.62%,58.87%,82.15%,and 59.53%,respectively.The XRD patterns indicated that Al and Si in the mullite phase(Al_(6)Si_(2)O_(13))were chlorinated during the carbochlorination process,resulting in the formation of mullite mesophases(Al_(4.75)Si_(1.25)O_(9.63) and Al_(1.83)Si_(1.08)O_(4.85)).After the carbochlorination process,Al was accumulated as AlCl_(3) in the condenser,while SiCl_(4) and TiCl_(4) were enriched in the exhaust gas,and CaCl_(2),MgCl_(2),and unreacted oxides remained in the residue for further recycling.

Feasible engineering of cathode electrolyte interphase enables the profoundly improved electrochemical properties in dual-ion battery

Dual-ion battery(DIB) composed of graphite cathode and lithium anode is regarded as an advanced secondary battery because of the low cost, high working voltage and environmental friendliness. However,DIB operated at high potential(usually ≥ 4.5 V versus Li+/Li) is confronted with severe challenges including electrolyte decomposition on cathode interface, and structural deterioration of graphite accompanying with anions de-/intercalation, hinder its cyclic life. To address those drawbacks and preserve the DIB virtues, a feasible and scalable surface modification is achieved for the commercial graphite cathode of mesocarbon microbead. In/ex-situ studies reveal that, such an interfacial engineering facilitates and reconstructs the formation of chemically stable cathode electrolyte interphase with better flexibility alleviating the decomposition of electrolyte, regulating the anions de-/intercalation behavior in graphite with the retainment of structural integrity and without exerting considerable influence on kinetics of anions diffusion. As a result, the modified mesocarbon microbead exhibits a much-extended cycle life with high capacity retention of 82.3% even after 1000 cycles. This study demonstrates that the interface modification of electrode and coating skeleton play important roles on DIB performance improvement, providing the feasible basis for practical application of DIB owing to the green and scalable coating procedures.

Enhanced electrode kinetics and properties via anionic regulation in polyanionic Na_(3+x)V_(2)(PO_(4))_(3-x)(P_(2)O_(7))_(x) cathode material

Mixing polyanion cathode materials are promising candidates for the development of next-generation batteries, owing to their structural robustness and low-volume changes, yet low conductivity of polyanion hinders their practical capacity. Herein, the anion-site regulation is proposed to elevate the electrode kinetics and properties of polyanionic cathode. Multivalent anion P_(2)O_(7)^(4-) is selected to substitute the PO_(4)^(3-) in Na_(3)V_(2)(PO_(4))_(3) (NVP) lattice and regulate the ratio of polyanion groups to prepare Na_(3+x)V_(2)(PO_(4))_(3-x)(P_(2)O_(7))_(x)(NVPP_(x), 0 ≤ x ≤ 0.15) materials.The optimal Na_(3.1)V_(2)(PO_(4))_(2.9)(P_(2)O_(7))_(0.1) (NVPP_(0.1)) material can deliver remarkably elevated specific capacity(104 mAh g^(-1) at 0.1 C, 60 mAh g^(-1) at 20 C, respectively), which is higher than those of NVP. Moreover, NVPP_(0.1) exhibits outstanding cyclic stability(91% capacity retention after 300 cycles at 1 C). Experimental analyses reveal that the regulation of anions improves the structure stability, increases the active Na occupancy in the lattice and accelerates the Na+migration kinetics. The strategy of anion-site regulation provides the researchers a reference for the design of new high-performance polyanionic materials.

Pulse generation of erbium-doped fiber laser based on liquid-exfoliated FePS3

As a preferable material in the field of photo-detection and catalysis,the characteristics of FePS3 in broad wavelength range have been proven by many experimental studies.However,FePS3 has not been used as a saturable absorber(SA)in fiber lasers yet.We propose and demonstrate the generation of a single wavelength and dual-wavelength based on an Er-doped fiber laser(EDFL)at 1.5μm by using an innovative FePS3 saturable absorber for the first time.The result shows that a stable passively Q-switched pulse can be generated,which demonstrates that the new two-dimensional(2D)material FePS3 served as SA provides a valid method to realize passively Q-switched laser.In addition,we achieve the output of the dual-wavelength pulse by properly rotating the polarization controller.To the best of our knowledge,the dual-wavelength pulse EDFL could be applied in biomedicine,spectroscopy,and sensing research.

Stability analysis of magnetization in a perpendicular magnetic layer driven by spin Hall effect

We investigate the stability of magnetization in free layer where the spin torque is induced by the spin Hall effect.In terms of the Landau–Liftshitz–Gilbert equation,we find the low-energy and high-energy equilibrium states,as well as the saddle points.The stability region is defined in the phase diagram spanned by the current density and the spin Hall angle.The spin Hall effect makes the previous saddle point into a stable state above a critical current.However,in the presence of magnetic field,the spin Hall effect leads to the opposite changes in the stable regions of the two low-energy states.

Carbon-coating-increased working voltage and energy density towards an advanced Na3V2(PO4)2F3@C cathode in sodium-ion batteries

One main challenge for phosphate cathodes in sodium-ion batteries(SIBs)is to increase the working voltage and energy density to promote its practicability.Herein,an advanced Na3V2(PO4)2F3@C cathode is prepared successfully for sodium-ion full cells.It is revealed that,carbon coating can not only enhance the electronic conductivity and electrode kinetics of Na3V2(PO4)2F3@C and inhibit the growth of particles(i.e.,shorten the Na^+-migration path),but also unexpectedly for the first time adjust the dis-/charging plateaux at different voltage ranges to increase the mean voltage(from 3.59 to 3.71 V)and energy density from 336.0 to 428.5 Wh kg^-1 of phosphate cathode material.As a result,when used as cathode for SIBs,the prepared Na3V2(PO4)2F3@C delivers much improved electrochemical properties in terms of larger specifc capacity(115.9 vs.93.5 mAh g^-1),more outstanding high-rate capability(e.g.,87.3 vs.60.5 mAh g^-1 at 10 C),higher energy density,and better cycling performance,compared to pristine Na3V2(PO4)2F3.Reasons for the enhanced electrochemical properties include ionicity enhancement of lattice induced by carbon coating,improved electrode kinetics and electronic conductivity,and high stability of lattice,which is elucidated clearly through the contrastive characterization and electrochemical studies.Moreover,excellent energy-storage performance in sodium-ion full cells further demonstrate the extremely high possibility of Na3V2(PO4)2F3@C cathode for practical applications.

High-ionicity fluorophosphate lattice via aliovalent substitution as advanced cathode materials in sodium-ion batteries

As a cathode for sodium-ion batteries(SIBs),Na3V2(PO4)2F3(NVPF)with 3D open framework is a promising candidate due to its high working voltage and large theoretical capacity.However,the severe capacity degradation and poor rate capability hinder its practical applications.The present study demonstrated the optimization of Na-storage performance of NVPF via delicate lattice modulation.Aliovalent substitution of V^(3^(+))at Na^(+)in NVPF induces the generation of electronic defects and expansion of Na^(+)-migration channels,resulting in the enhancement in electronic conductivity and acceleration of Na^(+)-migration kinetics.It is disclosed that the formed stronger Na O bonds with high ionicity than V O bonds lead to the significant increase in structural stability and ionicity in the Na^(+)-substituted NVPF(NVPF-Nax).The aforementioned effects of Na^(+)substitution achieve the unprecedented electrochemical performance in the optimized Na_(3.14)V1.93Na0.07(PO_(4))_(2)F_(3)(NVPF-Na_(0.07)).As a result,NVPF-Na0.07 delivers a high-rate capability(77.5 mAh g^(−1)at 20 C)and ultralong cycle life(only 0.027%capacity decay per cycle over 1000 cycles at 10 C).Sodium-ion full cells are designed using NVPF-Na0.07 as cathode and Se@reduced graphene oxide as anode.The full cells exhibit excellent wide-temperature electrochemical performance from−25 to 25C with an outstanding rate capability(96.3 mAh g^(−1)at 20 C).Furthermore,it delivered an excellent cycling performance over 300 cycles with a capacity retention exceeding 90%at 0.5 C under different temperatures.This study demonstrates a feasible strategy for the development of advanced cathode materials with excellent electrochemical properties to achieve high-efficiency energy storage.

钠离子电池Na_(0.62)K_(0.05)Mn_(0.7)Ni_(0.2)Co_(0.1)O_(2)正极材料:钾离子掺杂且{001}面稳定的中空多面体

钠离子电池中,正极材料至关重要,在很大程度上决定了整个电池的能量密度等性能.层状氧化物是钠离子电池中最有潜力的正极材料之一.然而,层状氧化物仍面临着不可逆相变、容量低、空气稳定性差和循环寿命短等缺点,限制了其实际应用.为了解决相关问题,本研究成功制备了中空结构的Na_(0.62)K_(0.05)Mn_(0.7)Ni_(0.2)Co_(0.1)O_(2)多面体正极材料.其中,少量的大尺寸钾离子实现了对材料中相应钠离子的取代;镍离子的较高氧化还原电位使得氧化物正极材料能够在空气中稳定保存.在100 mA g^(-1)电流密度下放电100次后,仍可保持115.0 mA h g^(-1)的放电比容量.在500 mA g^(-1)的较大电流密度下,材料仍然可实现104.1 mA h g^(-1)的较高放电比容量.研究结果表明,充放电过程中,氧化物正极材料的P2到O2的相变得到了有效地抑制.同时钾离子在层间的嵌入掺杂,使得氧化物正极的钠离子层间距增大,提升了钠离子的迁移速率.因此,Na_(0.62)K_(0.05)Mn_(0.7)Ni_(0.2)Co_(0.1)O_(2)应用于钠离子电池正极时展现出较大的吸引力和应用前景.

Nano self-assembly of fluorophosphate cathode induced by surface energy evolution towards high-rate and stable sodium-ion batteries

In the field of materials science and engineering,controlling over shape and crystal orientation remains a tremendous challenge.Herein,we realize a nano self-assembly morphology adjustment of Na3V2(PO4)2F3(NVPF)material,based on surface energy evolution by partially replacing V3+with aliovalent Mn2+.Crystal growth direction and surface energy evolution,main factors in inducing the nano self-assembly of NVPF with different shapes and sizes,are revealed by high-resolution transmission electron microscope combined with density functional theory.Furthermore,NVPF with a two-dimensional nanosheet structure(NVPF-NS)exhibits the best rate capability with 68 mAh·g−1 of specific capacity at an ultrahigh rate of 20 C and cycle stability with 80.7%of capacity retention over 1,000 cycles at 1 C.More significantly,when matched with Se@reduced graphene oxide(rGO)anode,NVPF-NS//Se@rGO sodium-ion full cells display a remarkable long-term stability with a high capacity retention of 93.8%after 500 cycles at 0.5 C and−25°C.Consequently,experimental and theoretical calculation results manifest that NVPF-NS demonstrates such superior performances,which can be mainly due to its inherent crystal structure and preferential orientation growth of{001}facets.This work will promise insights into developing novel architectural design strategies for high-performance cathode materials in advanced sodium-ion batteries.

Weakly-solvating electrolytes enable ultralow-temperature (-80°C) and high-power CF_(x)/Li primary batteries

Fluorinated carbons(CF_(x))/Li primary batteries with high theoretical energy density have been applied as indispensable energy storage devices with no need for rechargeability,yet plagued by poor rate capability and narrow temperature adaptability in actual scenarios.Herein,benefiting from precise solvation engineering for synergistic coordination of anions and low-affinity solvents,the optimized cyclic ether-based electrolyte is elaborated to significantly facilitate overall reaction dynamics closely correlated to lower desolvation barrier.As a result,the excellent rate(15 C,650 mAh g^(-1))at room-temperature and ultra-lowtemperature performance dropping to-80°C(495 mAh g^(-1)at average output voltage of 2.11 V)is delivered by the end of 1.5 V cut-off voltage,far superior to other organic liquid electrolytes.Furthermore,the CF_(x)/Li cell employing the high-loading electrode(18-22 mg cm^(-2))still yields 1,683 and 1,395 Wh kg^(-1)in the case of-40°C and-60°C,respectively.In short,the novel design strategy for cyclic ethers as basic solvents is proposed to enable the CF_(x)/Li battery with superb subzero performances,which shows great potential in practical application for extreme environments.

A unique co-recovery strategy of cathode and anode from spent LiFePO_(4) battery

Along with the explosive growth in the market of new energy electric vehicles,the demand for Li-ion batteries(LIBs)has correspondingly expanded.Given the limited life of LIBs,numbers of spent LIBs are bound to be produced.Because of the severe threats and challenges of spent LIBs to the environment,resources,and global sustainable development,the recycling and reuse of spent LIBs have become urgent.Herein,we propose a novel green and efficient direct recycling method,which realizes the concurrent reuse of LiFePO_(4)(LFP)cathode and graphite anode from spent LFP batteries.By optimizing the proportion of LFP and graphite,a hybrid LFP/graphite(LFPG)cathode was designed for a new type of dualion battery(DIB)that can achieve co-participation in the storage of both anions and cations.The hybrid LFPG cathode combines the excellent stability of LFP and the high conductivity of graphite to exhibit an extraordinary electrochemical performance.The best compound,i.e.,LFP:graphite=3:1,with the highest reversible capacity(~130 mAhg^(-1) at 25 mAg^(-1)),high voltage platform of 4.95 V,and outstanding cycle performance,was achieved.The specific diffusion behavior of Li^(+) and PF_(6)^(-) in the hybrid cathode was studied using electrode kinetic tests,further clarifying the working mechanism of DIBs.This study provides a new strategy toward the large-scale recycling of positive and negative electrodes of spent LIBs and establishes a precedent for designing new hybrid cathode materials for DIBs with superior performance using spent LIBs.

Flexible quasi-solid-state sodium-ion full battery with ultralong cycle life,high energy density and high-rate capability

Flexible power sources featuring high-performance,prominent flexibility and raised safety have received mounting attention in the area of wearable electronic devices.However,many great challenges remain to be overcome,notably the design and fabrication of flexible electrodes with excellent electrochemical performance and matching them with safe and reliable electrolytes.Herein,a facile approach for preparing flexible electrodes,which employs carbon cloth derived from commercial cotton cloth as the substrate of cathode and a flexible anode,is proposed and investigated.The promising cathode(NVPOF@FCC)with high conductivity and outstanding flexibility is prepared by efficiently coating Na_(3)V_(2)(PO_(4))_(2)O_(2)F(NVPOF)on flexible carbon cloth(FCC),which exhibits remarkable electrochemical performance and the significantly improved reaction kinetics.More importantly,a novel flexible quasi-solid-state sodium-ion full battery(QSFB)is feasibly assembled by sandwiching a P(VDF-HFP)-NaClO_(4) gel-polymer electrolyte film between the advanced NVPOF@FCC cathode and FCC anode.And the QSFBs are further evaluated in flexible pouch cells,which not only demonstrates excellent energy-storage performance in aspect of great cycling stability and high-rate capability,but also impressive flexibility and safety.This work offers a feasible and effective strategy for the design of flexible electrodes,paving the way for the progression of practical and sustainable flexible batteries.

Suppressing oxygen redox in layered oxide cathode of sodium-ion batteries with ribbon superstructure and solid-solution behavior

Sodium-ion batteries(SIBs)are proved as one of the most acceptable candidates for replacing lithium-ion batteries in some fields by virtue of a similar“rocking chair”mechanism and the abundance of sodium.The voltage,rate performance,and energy density of these batteries are mainly determined by the cath-odes.Hence,a Li-Ni-Co co-substituted P2-Na_(0.67)[Li_(0.1)(Mn_(0.7)Ni_(0.2)Co_(0.1))_(0.9)]O_(2)(NLMNC)with ribbon super-structure is prepared with the aim of multi-ion synergistic modification.Owing to the addition of Ni and Co,the Jahn-Teller distortion of Mn can be suppressed corresponding with the improved structural stability,and a little bit of oxygen redox activities is triggered.When with the substitution of 10%Li,the X-ray diffraction(XRD)peaks of NLMNC show the ribbon superstructure at about 21°and 22°.The smooth charge/discharge profiles of the NLMNC cathode exhibit the solid-solution reaction.In addition,the platform at high voltage disappears corresponding with the existing oxygen redox activities being suppressed which may be related to the ribbon superstructure and the promotion of the Ni redox.Such NLMNC cathode can deliver a reversible discharge capacity of 123.5 mA h g^(-1)at 10 mA g^(-1).Even if the current density increases to 500 mA g^(-1),a reversible discharge capacity of 112.8 mA h g^(-1)still can be ob-tained.The distinguished cycling stability is related to the reversible migration of Li+between the metal oxide layer and the interlayer and low volume change during cycling.It is also needing to be mentioned that the capacity retention of NLMNC cathode is about 94.4%(based on the highest discharge capacity)after 100 cycles.This work presents an effective route to develop high-performance cathodes for SIBs.

Advanced flame-retardant electrolyte for highly stabilized K-ion storage in graphite anode

Although graphite anodes operated with representative de/intercalation patterns at low potentials are considered highly desirable for K-ion batteries,the severe capacity fading caused by consecutive reduction reactions on the aggressively reactive surface is inevitable given the scarcity of effective protecting layers.Herein,by introducing a flame-retardant localized high-concentration electrolyte with retentive solvation configuration and relatively weakened anion-coordination and non-solvating fluorinated ether,the rational solid electrolyte interphase characterized by well-balanced inorganic/organic components is tailored in situ.This effectively prevented solvents from excessively decomposing and simultaneously improved the resistance against K-ion transport.Consequently,the graphite anode retained a prolonged cycling capability of up to 1400 cycles(245 mA h g,remaining above 12 mon)with an excellent capacity retention of as high as 92.4%.This is superior to those of conventional and high-concentration electrolytes.Thus,the optimized electrolyte with moderate salt concentration is perfectly compatible with graphite,providing a potential application prospect for K-storage evolution.

Nano-SnO_(2) Decorated Carbon Cloth as Flexible,Self-supporting and Additive-Free Anode for Sodium/Lithium-Ion Batteries

In this study,nano-sized SnO_(2) decorated on carbon cloth(SnO_(2)/CC)is prepared through a simple and facile solid method.The nano-sized SnO_(2) is uniformly distributed on the surface of carbon fibers in carbon cloth,providing sufficient free space to relieve volume expansion and reduce electrode pulverization during cycling.The as-prepared SnO_(2)/CC as a flexible,self-supporting and additive-free anode electrode for sodium-ion/lithium-ion batteries(SIBs/LIBs)can demonstrate outstanding electrochemical performance.SnO_(2)/CC after annealing at 350℃(SC-350)as an anode for SIBs can deliver a reversible capacity of 0.587 mA h cm^(-2)at the current density of 0.3 mA cm^(-2)after 100 cycles.In addition,when cycling at 1.5 mA cm^(-2),SC-350 can maintain 1.69 mA h cm^(-2)after 500 cycles when used as LIB anode.These results illustrate that the as-prepared SnO_(2)/CC can be a promising flexible anode material for flexible SIBs/LIBs and provide a simple and practical method for designing new flexible electrode materials.

Longitudinal dispersion coefficients of pollutants in compound channels with vegetated floodplains

The characteristics of the longitudinal dispersion of pollutants in compound channels remain unclear. This study examines the relationships among the vegetation density, the width of the floodplain, the water depth ratio, the cross-sectional mean velocity, and the longitudinal dispersion coefficient of a symmetrical compound channel with a rigid non-submerged vegetated floodplain. The longitudinal dispersion coefficient is found to increase significantly with the presence of vegetation on floodplains, and is positively correlated with the plant density. When the density of the vegetation on the floodplains exceeds a certain value, the dispersion coefficient no longer changes with the vegetation density. The longitudinal dispersion coefficient is found to increase with the increase of the width of the floodplain. Moreover, the combined effects of the mean velocity and the water depth ratio have a positive correlation with the dispersion coefficient. The effects of the vegetation on the longitudinal dispersion coefficient in the channels with various cross-sections are also compared. The compound channels with a vegetated floodplain are found to differ significantly from the channels with a rectangular cross-section.

Advanced cathode for dual-ion batteries: Waste-to-wealth reuse of spent graphite from lithium-ion batteries

The amount of spent lithium-ion batteries (LIBs) is constantly increasing as their popularity grows. It is important todevelop a recycling method that cannot only convert large amounts of waste anode graphite into high value-addedproducts but is also simple and environmentally friendly. In this work, spent graphite from an anode was transformed into a cathode for dual-ion batteries (DIBs) through a two-step treatment. This method enables the crystalstructure and morphology of spent graphite to recover from the adverse effects of long cycling and be restored to aregular layered structure with appropriate layer spacing for anion intercalation. In addition, pyrolysis of the solidelectrolyte interphase into an amorphous carbon layer prevents the electrode from degrading and improves itscycling performance. The recycled negative graphite has a high reversible capacity of 87 mAh g^(-1) at 200 mA g^(-1),and its rate performance when used as a cathode in DIBs is comparable to that of commercial graphite. This simplerecycling idea turns spent anode graphite into a cathode material with attractive potential and superior electrochemical performance, genuinely achieving sustainable energy use. It also provides a new method for recoveringexhausted batteries.

Prospects for managing end-of-life lithium-ion batteries:Present and future

The accelerating electrification has sparked an explosion in lithium-ion batteries(LIBs)consumption.As the lifespan declines,the substantial LIBs will flow into the recycling market and promise to spawn a giant recycling system.Nonetheless,since the lack of unified guiding standard and nontraceability,the recycling of end-of-life LIBs has fallen into the dilemma of low recycling rate,poor recycling efficiency,and insignificant benefits.Herein,tapping into summarizing and analyzing the current status and challenges of recycling LIBs,this outlook provides insights for the future course of full lifecycle management of LIBs,proposing gradient utilization and recycling-target predesign strategy.Further,we acknowledge some recommendations for recycling waste LIBs and anticipate a collaborative effort to advance sustainable and reliable recycling routes.

Aneurysmal Bone Cyst of the Orbit

Aneurysmal bone cyst （ABC） is an uncommon benign lesion with a reported incidence rate of 0.14 cases for every 1,000,000 people.ABC can occur in any part of the skeletal system but is mainly detected in the long bones.Orbit involvement is rare （〈1% of all ABCs）.In this article,we presented two female patients aged 49 and 33 years old respectively who suffered from ABC.After successful surgical removal of the cyst via frontal craniotomy and simple curettage,the patients recovered well and have been in good health throughout the 2.5-4.5 years of follow-up.

Effects of a combined infection with Paranosema locustae and Beauveria bassiana on Locusta migratoria and its gut microflora

Even though Paranosema locustae is widely used in China as a biological agent for controlling grasshoppers,the mortality rate is initially quite low.This study sought to determine whether the simultaneous use of P.locustae and Beauveria bassiana would be a more effective control strategy.Additionally,changes in the intestinal microbial communities of migratory locusts infected with the two pathogens were analyzed to investigate the roles of gut microbes in pathogen-host interactions.The mortality rate of locusts inoculated with B.bassiana and P.locustae simultaneously was not significantly higher than expected but the mortality rates of locusts inoculated with B.bassiana 3,6,and 9 days after inoculation with P.locustae were significantly higher than if their effects were additive,indicating synergism.A MiSeq analysis found that Weissella was the most common bacterium,representing 41.48%and 51.62%of the total bacteria in the mid-and hindguts,respectively,and the bacterial declines were greatest during dual infections with B.bassiana and P.locustae.The appropriately timed combined application of P.locustae and B.bassiana was more effective against locusts than either treatment alone.Moreover,the combined inoculation of the two pathogens changed the gut microflora of locusts,indicating the potential relevancy of their synergistic effects on locust control.