查看更多>>摘要：The poor electrochemical performance of all-solid-state batteries(ASSBs),which is assemblied by Ni-rich cathode and poly(ethylene oxide)(PEO)-based electrolytes,can be attributed to unstable cathodic inter-face and poor crystal structure stability of Ni-rich cathode.Several coating strategies are previously employed to enhance the stability of the cathodic interface and crystal structure for Ni-rich cathode.However,these methods can hardly achieve simplicity and high efficiency simultaneously.In this work,polyacrylic acid(PAA)replaced traditional PVDF as a binder for cathode,which can achieve a uniform PAA-Li(LixPAA(0＜x ≤ 1))coating layer on the surface of single-crystal LiNi0.83Co0.12Mn0.05O2(SC-NCM83)due to H+/Li+exchange reaction during the initial charging-discharging process.The formation of PAA-Li coating layer on cathode can promote interfacial Li+transport and enhance the stability of the cathodic interface.Furthermore,the partially-protonated surface of SC-NCM83 casued by H+/Li+exchange reaction can restrict Ni ions transport to enhance the crystal structure stability.The proposed SC-NCM83-PAA exhibits superior cycling performance with a retention of 92％compared with that(57.3％)of SC-NCM83-polyvinylidene difluoride(PVDF)after 200 cycles.This work provides a practical strategy to construct high-performance cathodes for ASSBs.
查看更多>>摘要：The recycling and reutilization of spent lithium-ion batteries(LIBs)have become an important measure to alleviate problems like resource scarcity and environmental pollution.Although some progress has been made,battery recycling technology still faces challenges in terms of efficiency,effectiveness and environmental sustainability.This review aims to systematically review and analyze the current status of spent LIB recycling,and conduct a detailed comparison and evaluation of different recycling processes.In addition,this review introduces emerging recycling techniques,including deep eutectic solvents,mol-ten salt roasting,and direct regeneration,with the intent of enhancing recycling efficiency and diminish-ing environmental repercussions.Furthermore,to increase the added value of recycled materials,this review proposes the concept of upgrading recycled materials into high value-added functional materials,such as catalysts,adsorbents,and graphene.Through life cycle assessment,the paper also explores the economic and environmental impacts of current battery recycling and highlights the importance that future recycling technologies should achieve a balance between recycling efficiency,economics and envi-ronmental benefits.Finally,this review outlines the opportunities and challenges of recycling key mate-rials for next-generation batteries,and proposes relevant policy recommendations to promote the green and sustainable development of batteries,circular economy,and ecological civilization.
查看更多>>摘要：This study investigates the effects of Fe on the oxygen-evolution reaction(OER)in the presence of Au.Two distinct areas of OER were identified:the first associated with Fe sites at low overpotential(～330 mV),and the second with Au sites at high overpotential(～870 mV).Various factors such as surface Fe concentration,electrochemical method,scan rate,potential range,concentration,method of adding K2FeO4,nature of Fe,and temperature were varied to observe diverse behaviors during OER for FeOxHy/Au.Trace amounts of Fe ions had a significant impact on OER,reaching a saturation point where the activity did not increase further.Strong electronic interaction between Fe and Au ions was indicated by X-ray photoelectron spectroscopy(XPS)and electron paramagnetic resonance(EPR)analyses.In situ visible spectroscopy confirmed the formation of FeO42-during OER.In situ Mössbauer and surface-enhanced Raman spectroscopy(SERS)analyses suggest the involvement of Fe-based species as interme-diates during the rate-determining step of OER.A lattice OER mechanism based on FeOxHy was proposed for operation at low overpotentials.Density functional theory(DFT)calculations revealed that Fe oxide,Fe-oxide clusters,and Fe doping on the Au foil exhibited different activities and stabilities during OER.The study provides insights into the interplay between Fe and Au in OER,advancing the understanding of OER mechanisms and offering implications for the design of efficient electrocatalytic systems.
查看更多>>摘要：Blade batteries are extensively used in electric vehicles,but unavoidable thermal runaway is an inherent threat to their safe use.This study experimentally investigated the mechanism underlying thermal run-away propagation within a blade battery by using a nail to trigger thermal runaway and thermocouples to track its propagation inside a cell.The results showed that the internal thermal runaway could prop-agate for up to 272 s,which is comparable to that of a traditional battery module.The velocity of the ther-mal runaway propagation fluctuated between 1 and 8 mm s-1,depending on both the electrolyte content and high-temperature gas diffusion.In the early stages of thermal runaway,the electrolyte participated in the reaction,which intensified the thermal runaway and accelerated its propagation.As the battery temperature increased,the electrolyte evaporated,which attenuated the acceleration effect.Gas diffusion affected thermal runaway propagation through both heat transfer and mass transfer.The experimental results indicated that gas diffusion accelerated the velocity of thermal runaway propagation by 36.84％.We used a 1D mathematical model and confirmed that convective heat transfer induced by gas diffusion increased the velocity of thermal runaway propagation by 5.46％-17.06％.Finally,the temperature rate curve was analyzed,and a three-stage mechanism for internal thermal runaway propagation was pro-posed.In Stage Ⅰ,convective heat transfer from electrolyte evaporation locally increased the temperature to 100 ℃.In Stage Ⅱ,solid heat transfer locally increases the temperature to trigger thermal runaway.In Stage Ⅲ,thermal runaway sharply increases the local temperature.The proposed mechanism sheds light on the internal thermal runaway propagation of blade batteries and offers valuable insights into safety considerations for future design.
查看更多>>摘要：The safety valve is an important component to ensure the safe operation of lithium-ion batteries(LIBs).However,the effect of safety valve type on the thermal runaway(TR)and gas venting behavior of LIBs,as well as the TR hazard severity of LIBs,are not known.In this paper,the TR and gas venting behavior of three 100 A h lithium iron phosphate(LFP)batteries with different safety valves are investigated under overheating.Compared to previous studies,the main contribution of this work is in studying and evalu-ating the effect of gas venting behavior and TR hazard severity of LFP batteries with three safety valve types.Two significant results are obtained:(I)the safety valve type dominates over gas venting pressure of battery during safety venting,the maximum gas venting pressure of LFP batteries with a round safety valve is 3320 Pa,which is one order of magnitude higher than other batteries with oval or cavity safety valve;(Ⅱ)the LFP battery with oval safety valve has the lowest TR hazard as shown by the TR hazard assessment model based on gray-fuzzy analytic hierarchy process.This study reveals the effect of safety valve type on TR and gas venting,providing a clear direction for the safety valve design.
查看更多>>摘要：Fluorinated carbons CFx hold the highest theoretical energy density(e.g.,2180 W h kg-1when x=1)among all cathode materials of lithium primary batteries.However,the low conductivity and severe polarization limit it to achieve its theory.In this study,we design a new electrolyte,namely 1 M LiBF4 DMSO:DOL(1:9 vol.),achieving a high energy density in Li/CFx primary cells.The DMSO with a small molecular size and high donor number successfully solvates Li+into a defined Li+-solvation structure.Such solvated Li+can intercalate into the large-spacing carbon layers and achieve an improved capacity.Consequently,when discharged to 1.0 V,the CF1.12 cathode demonstrates a specific capacity of 1944 mA h g-1 with a specific energy density of 3793 W h kg 1.This strategy demonstrates that design-ing the electrolyte is powerful in improving the electrochemical performance of CFx cathode.
查看更多>>摘要：The d-d orbital coupling induced by crystal-phase engineering can effectively adjust the electronic struc-ture of electrocatalysts,thus showing significant catalytic performance,while it has been rarely explored in electrochemical acetonitrile reduction reaction(ARR)to date.Herein,we successfully realize the struc-tural transformation of PdCu metallic aerogels(MAs)from face-centered cubic(FCC)to body-centered cubic(BCC)through annealing treatment.Specifically,the BCC PdCu MAs exhibit excellent ARR perfor-mance with high ethylamine selectivity of 90.91％,Faradaic efficiency of 88.60％,yield rate of 316.0 mmol h-1 g-1Pd1+Cu and long-term stability for consecutive electrolysis within 20 h at-0.55 V vs.rever-sible hydrogen electrode,outperforming than those of FCC PdCu MAs.Under the membrane electrode assembly system,BCC PdCu MAs also demonstrate excellent ethylamine yield rate of 389.5 mmol h-1 g-1PdCu-1 Density functional theory calculation reveals that the d-d orbital coupling in BCC PdCu MAs results in an evident correlation effect for the interaction of Pd and Cu sites,which boosts up the Cu sites electronic activities to enhance ARR performance.Our work opens a new route to develop efficient ARR electrocata-lysts from the perspective of crystalline structure transformation.
查看更多>>摘要：Developing technologies that can be applied simultaneously in battery thermal management(BTM)and thermal runaway(TR)mitigation is significant to improving the safety of lithium-ion battery systems.Inorganic phase change material(PCM)with nonflammability has the potential to achieve this dual func-tion.This study proposed an encapsulated inorganic phase change material(EPCM)with a heat transfer enhancement for battery systems,where Na2HPO4·12H2O was used as the core PCM encapsulated by sil-ica and the additive of carbon nanotube(CNT)was applied to enhance the thermal conductivity.The microstructure and thermal properties of the EPCM/CNT were analyzed by a series of characterization tests.Two different incorporating methods of CNT were compared and the proper CNT adding amount was also studied.After preparation,the battery thermal management performance and TR propagation mitigation effects of EPCM/CNT were further investigated on the battery modules.The experimental results of thermal management tests showed that EPCM/CNT not only slowed down the temperature ris-ing of the module but also improved the temperature uniformity during normal operation.The peak bat-tery temperature decreased from 76 ℃ to 61.2 ℃ at 2 C discharge rate and the temperature difference was controlled below 3 ℃.Moreover,the results of TR propagation tests demonstrated that non-flammable EPCM/CNT with good heat absorption could work as a TR barrier,which exhibited effective mitigation on TR and TR propagation.The trigger time of three cells was successfully delayed by 129,474 and 551 s,respectively and the propagation intervals were greatly extended as well.
查看更多>>摘要：Owing to the distinctive structural characteristics,vanadium nitride(VN)is highly regarded as a catalyst for oxygen reduction reaction(ORR)in zinc-air batteries(ZABs).However,VN exhibits limited intrinsic ORR activity due to the weak adsorption ability to O-containing species.Here,the S-doped VN anchored on N,S-doped multi-dimensional carbon(S-VN/Co/NS-MC)was constructed using the solvothermal and in-situ doping methods.Incorporating sulfur atoms into VN species alters the electron spin state of vana-dium in the S-VN/Co/NS-MC for regulating the adsorption energy of vanadium sites to oxygen molecules.The introduced sulfur atoms polarize the V 3dz2 electrons,shifting spin-down electrons closer to the Fermi level in the S-VN/Co/NS-MC.Consequently,the introduction of sulfur atoms into VN species enhances the adsorption energy of vanadium sites for oxygen molecules.The*OOH dissociation transi-tions from being unspontaneous on the VN surface to a spontaneous state on the S-doped VN surface.Then,the ORR barrier on the S-VN/Co/NS-MC surface is reduced.The S-VN/Co/NS-MC demonstrates a higher half-wave potential and limiting current density compared to the VN/Co/N-MC.The S-VN/Co/NS-MC-based liquid ZABs display a power density of 195.7 mW cm-2,a specific capacity of 815.7 mA h g-1,and a cycling stability exceeding 250 h.The S-VN/Co/NS-MC-based flexible ZABs are suc-cessfully employed to charge both a smart watch and a mobile phone.This approach holds promise for advancing the commercial utilization of VN-based catalysts in ZABs.
查看更多>>摘要：Although metal oxide compounds are considered as desirable anode materials for potassium-ion batter-ies(PIBs)due to their high theoretical capacity,the large volume variation remains a key issue in realizing metal oxide anodes with long cycle life and excellent rate property.In this study,polypyrrole-encapsulated Sb2WO6(denoted Sb2WO6@PPy)microflowers are synthesized by a one-step hydrothermal method followed by in-situ polymerization and coating by pyrrole.Leveraging the nanosheet-stacked Sb2WO6 microflower structure,the improved electronic conductivity,and the architectural protection offered by the PPy coating,Sb2WO6@PPy exhibits boosted potassium storage properties,thereby demon-strating an outstanding rate property of 110.3 mA h g-1 at 5 A g-1 and delivering a long-period cycling stability with a reversible capacity of 197.2 mA h g-1 after 500 cycles at 1 A g-1.In addition,the conver-sion and alloying processes of Sb2WO6@PPy in PIBs with the generation of intermediates,K2WO4 and K3Sb,is determined by X-ray photoelectron spectroscopy,transmission electron microscopy,and ex-situ X-ray diffraction during potassiation/depotassiation.Density functional theory calculations demon-strate that the robust coupling between PPy and Sb2WO6 endues it with a much stronger total density of states and a built-in electric field,thereby increasing the electronic conductivity,and thus effectively reduces the K*diffusion barrier.
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