查看更多>>摘要：Nowadays,the global climate is constantly being destroyed and the fluctuations in ambient temperature are becoming more frequent.However,conventional single-mode thermal management strategies(heat-ing or cooling)failed to resolve such dynamic temperature changes.Moreover,developing thermal man-agement devices capable of accommodating these temperature variations while remaining simple to fabricate and durable has remained a formidable obstacle.To address these bottlenecks,we design and successfully fabricate a novel dual-mode hierarchical(DMH)composite film featuring a micro-nanofiber network structure,achieved through a straightforward two-step continuous electrospinning process.In cooling mode,it presents a high solar reflectivity of up to 97.7％and an excellent atmospheric transparent window(ATW)infrared emissivity of up to 98.9％.Noted that this DMH film could realize a cooling of 8.1 ℃ compared to the ambient temperature outdoors.In heating mode,it also exhibits a high solar absorptivity of 94.7％and heats up to 11.9 ℃ higher than black cotton fabric when utilized by indi-viduals.In practical application scenarios,a seamless transition between efficient cooling and heating is achieved by simply flipping the film.More importantly,the DMH film combining the benefits of compos-ites demonstrates portability,durability,and easy-cleaning,promising to achieve large-scale production and use of thermally managed textiles in the future.The energy savings offered by film applications pro-vide a viable solution for the early realization of carbon neutrality.
查看更多>>摘要：Lithium-sulfur(Li-S)batteries are promising for high energy-storage applications but suffer from sluggish conversion reaction kinetics and substantial lithium sulfide(Li2S)oxidation barrier,especially under high sulfur loadings.Here,we report a Li cation-doped tungsten oxide(LixWOx)electrocatalyst that efficiently accelerates the S↔Li2S interconversion kinetics.The incorporation of Li dopants into WOx cationic vacan-cies enables bidirectional electrocatalytic activity for both polysulfide reduction and Li2S oxidation,along with enhanced Li+diffusion.In conjunction with theoretical calculations,it is discovered that the improved electrocatalytic activity originates from the Li dopant-induced geometric and electronic struc-tural optimization of the LixWOx,which promotes the anchoring of sulfur species at favourable adsorp-tion sites while facilitating the charge transfer kinetics.Consequently,Li-S cells with the LixWOx bidirectional electrocatalyst show stable cycling performance and high sulfur utilization under high sul-fur loadings.Our approach provides insights into cation engineering as an effective electrocatalyst design strategy for advancing high-performance Li-S batteries.
查看更多>>摘要：The practical application of rechargeable lithium metal batteries(LMBs)encounters significant chal-lenges due to the notorious dendrite growth triggered by uneven Li deposition behaviors.In this work,a mechanically robust and single-ion-conducting interfacial layer,fulfilled by the strategic integration of flexible cellulose acetate(CA)matrix with rigid graphene oxide(GO)and LiF fillers(termed the CGL layer),is rationally devised to serve as a stabilizer for dendrite-free lithium(Li)metal batteries.The GCL film exhibits favorable mechanical properties with high modulus and flexibility that help to relieve interface fluctuations.More crucially,the electron-donating carbonyl groups(C=O)enriched in GCL foster a strengthened correlation with Li+,which availably aids the Li+desolvation process and expedites facile Li+mobility,yielding exceptional Li+transference number of 0.87.Such single-ion conductive properties regulate rapid and uniform interfacial transport kinetics,mitigating the growth of Li dendrites and the decomposition of electrolytes.Consequently,stable Li anode with prolonged cycle stabilities and flat deposition morphologies are realized.The Li||LiFePO4 full cells with CGL protective layer render an out-standing cycling capability of 500 cycles at 3 C,and an ultrahigh capacity retention of 99.99％for over 220 cycles even under harsh conditions.This work affords valuable insights into the interfacial regulation for achieving high-performance LMBs.
查看更多>>摘要：Solid-state polymer electrolytes(SPEs)capable of withstanding high voltage are considered to be key for next-generation energy storage devices with inherent safety as well as high energy density.This study involves the rational design of solid-state-C=N functionalized P(VEC1-CEA0.3)/LiTFSI@CE SPEs and its synthesis by in-situ free radical polymerization of vinyl ethylene carbonate(VEC)and 2-cyanoethyl acry-late(CEA).In situ polymerization yields electrode/electrolyte interfaces with low interfacial resistance,forming a stable SEI layer enriched with LiF,Li3N,and RCOOLi,ensuring stable Li plating/stripping for over 1400 h.The-C=N moiety renders the αH on the adjacent αC positively charged,thereby endowing it with the capability to anchor TFSI-.Simultaneously,the incorporation of-C=N moiety diminishes the electron-donating ability of the C=O,C-O-C,and-C≡N functional groups,facilitating not only the ion conductivity enhancement but also a more rapid Li+migration proved by DFT theoretical calculations and Raman spectroscopy.At room temperature,tLi+of 0.60 for P(VEC1-CEA0.3)/LiTFSI@CE SPEs is achieved when the ionic conductivity σLi+is 2.63 x 10-4 S cm-1 and the electrochemical window is expanded to 5.0 V.Both coin cells with high-areal-loading cathodes and the 6.5-mAh pouch cell,exhibit stable charge/discharge cycling.At 25 ℃,the 4.45-V Li|P(VEC1-CEA0.3)/LiTFSI@CE|LiCoO2 battery performs stable cycling over 200 cycles at 0.2 C,with a capacity retention of 82.1％.
查看更多>>摘要：The poor compatibility of ester electrolytes with lithium metal anode severely limits its use in high volt-age lithium metal batteries(LMBs).In this work,a bidentate solvent 1,2-diethoxyethane(DEE)is intro-duced into ester electrolyte to regulate the ion-dipole interactions to enhance the solubility of LiNO3,which enables compatibility with Li anode and maintains the high voltage cathode stability.In the designed electrolyte,the steric effect of DEE facilitates the participation of NO3-and PF6 anions in the Li+solvation structure,thus promoting the generation of inorganic-rich solid electrolyte interphase(SEI).And the low viscosity of DEE also ensures that the ester electrolyte poses good interfacial wettabil-ity.As a result,our designed electrolyte enables the high-loading Li||NCM622 and Li||NCM811(～3 mA h cm-2)full cells to achieve stable cycling over 200 cycles,8 times longer than that of a conventional ester electrolyte.This work suggests that regulation of intermolecular interactions in conventional ester elec-trolytes is a scalable and effective approach to achieve excellent electrochemical performance of LMBs.
查看更多>>摘要：Rechargeable metal-ion batteries,such as lithium-ion batteries(LIBs)and sodium-ion batteries(SIBs),have raised more attention because of the large demand for energy storage solutions.Undoubtedly,elec-trode materials and electrolytes are key parts of batteries,exhibiting critical influence on the reversible capacity and span life of the metal-ion battery.Nonetheless,researchers commonly express concerns regarding the stability of both electrodes and electrolytes.Given its commendable stability attributes,high-entropy materials have garnered widespread acclaim and have been applied in many fields since their inception,notably in energy storage.However,while certain high-entropy designs have achieved substantial breakthroughs,some have failed to meet anticipated outcomes within the high energy den-sity energy storage materials.Moreover,there is a lack of comprehensive summary research on the cor-responding mechanisms and design principles of high-entropy designs.This review examines the current high-entropy designs for cathodes,anodes,and electrolytes,aiming to summarize the design principle,potential mechanisms,and electrochemical performance.We focus on their structural characteristics,interface characteristics,and prospective development trends.At last,we provide a fair evaluation along-side succinct development suggestions.
查看更多>>摘要：Understanding and manipulating the structural evolution of water oxidation electrocatalysts lays the foundation to finetune their catalytic activity.Herein,we present a synthesis of NiSe2-Ce2(CO3)2O heterostructure and demonstrate the efficacy of interfacial Ce2(CO3)2O in promoting the formation of cat-alytically active centers to improve oxygen evolution activity.In-situ Raman spectroscopy shows that incorporation of Ce2(CO3)2O into NiSe2 causes a cathodic shift of the Ni2+→Ni3+transition potential.Operando electrochemical impedance spectroscopy reveals that strong electronic coupling at heteroge-neous interface accelerates charge transfer process.Furthermore,density functional theory calculations suggest that actual catalytic active species of NiOOH transformed from NiSe2,which is coupled with Ce2(CO3)2O,can optimize electronic structure and decrease the free energy barriers toward fast oxygen evolution reaction(OER)kinetics.Consequently,the resultant NiSe2-Ce2(CO3)2O electrode exhibits remarkable electrocatalytic performance with low overpotentials(268/304 mV@50/100 mA cm-2)and excellent stability(50 mA cm-2 for 120 h)in the alkaline electrolyte.This work emphasizes the signifi-cance of modulating the dynamic changes in developing efficient electrocatalyst.
Johnny Saavedra-LopezStephen D.DavidsonPaul H.HumbleDan R.Bottenus...
481-493页
查看更多>>摘要：Here we demonstrate the proof-of-concept for microchannel reactive distillation for alcohol-to-jet appli-cation:combining ethanol/water separation and ethanol dehydration in one unit operation.Ethanol is first distilled into the vapor phase,converted to ethylene and water,and then the water co-product is condensed to shift the reaction equilibrium.Process intensification is achieved through rapid mass trans-fer-ethanol stripping from thin wicks using novel microchannel architectures-leading to lower resi-dence time and improved separation efficiency.Energy savings are realized with integration of unit operations.For example,heat of condensing water can offset vaporizing ethanol.Furthermore,the dehy-dration reaction equilibrium shifts towards completion by immediate removal of the water byproduct upon formation while maintaining aqueous feedstock in the condensed phase.For aqueous ethanol feed-stock(40％w),71％ethanol conversion with 91％selectivity to ethylene was demonstrated at 220 ℃,600 psig,and 0.28 h-1 wt hour space velocity.2.7 stages of separation were also demonstrated,under these conditions,using a device length of 8.3 cm.This provides a height equivalent of a theoretical plate(HETP),a measure of separation efficiency,of～3.3 cm.By comparison,conventional distillation packing provides an HETP of～30 cm.Thus,9.1 x reduction in HETP was demonstrated over conventional technology,pro-viding a means for significant energy savings and an example of process intensification.Finally,prelim-inary process economic analysis indicates that by using microchannel reactive distillation technology,the operating and capital costs for the ethanol separation and dehydration portion of an envisioned alcohol-to-jet process could be reduced by at least 35％and 55％,respectively,relative to the incumbent technol-ogy,provided future improvements to microchannel reactive distillation design and operability are made.
查看更多>>摘要：The efficacy of the oxygen reduction reaction(ORR)in fuel cells can be significantly enhanced by optimiz-ing cobalt-based catalysts,which provide a more stable alternative to iron-based catalysts.However,their performance is often impeded by weak adsorption of oxygen species,leading to a 2e-pathway that negatively affects fuel cell discharge efficiency.Here,we engineered a high-density cobalt active center catalyst,coordinated with nitrogen and sulfur atoms on a porous carbon substrate.Both experimental and theoretical analyses highlighted the role of sulfur atoms as electron donors,disrupting the charge symmetry of the original Co active center and promoting enhanced interaction with Co 3d orbitals.This modification improves the adsorption of oxygen and reaction intermediates during ORR,signifi-cantly reducing the production of hydrogen peroxide(H2O2).Remarkably,the optimized catalyst demon-strated superior fuel cell performance,with peak power densities of 1.32 W cm-2 in oxygen and 0.61 W cm-2 in air environments,respectively.A significant decrease in H2O2 by-product accumulation was observed during the reaction process,reducing catalyst and membrane damage and consequently improving fuel cell durability.This study emphasizes the critical role of coordination symmetry in Co/N/C catalysts and proposes an effective strategy to enhance fuel cell performance.
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