查看更多>>摘要：The shuttle effect is among the most characteristic and formidable challenges in the pursuit of high-performance lithium-sulfur(Li-S)batteries.Herein,phosphorylated cellulose nanofibers(pCNF)are intentionally engineered to establish an ion-sieving barrier against polysulfide shuttling and thereby improve battery performance.The phosphorylation,involving the grafting of phosphate groups onto the cellulose backbone,imparts an exceptional electronegativity that repels the polysulfide anions from penetrating through the separator.Moreover,the electrolyte wettability and Li+transfer can be signifi-cantly promoted by the polar nature of pCNF and the facile Li+disassociation.As such,rational ion man-agement is realized,contributing to enhanced reversibility in both sulfur and lithium electrochemistry.As a result,Li-S cells equipped with the self-standing pCNF separator demonstrate outstanding long-term cyclability with a minimum fading rate of 0.013％per cycle over 1000 cycles at 1 C,and a decent areal capacity of 5.37 mA h cm-2 even under elevated sulfur loading of 5.0 mg cm-2 and limited elec-trolyte of 6.0 mL g-1.This work provides a facile and effective pathway toward the well-tamed shuttle effect and highly durable Li-S batteries.
查看更多>>摘要：Although heteroatom doping is an effective way to improve the catalytic activity of transition metal phosphides(TMPs),the mechanism of activity enhancement needs to be further refined.To this end,we synthesized a Co-doped Ni2P catalyst as a research model and found that the introduction of hetero-geneous Co reconstructed the charge distribution around the P site,which effectively enhanced the hydrogen evolution reaction(HER)activity of the pure Ni2P.Based on in-situ Raman real-time monitoring technology,we monitored for the first time that Co doping triggered a switch of the active site(from the original Co-active site to the P-active site),which promoted the adsorption of H2O to enhance the HER activity.The density functional theory(DFT)calculations indicated that the P site of Co-Ni2P expressed the highest activity and the Ni site of pure Ni2P expressed the highest activity,which further confirms the in-situ Raman monitoring results.The active site turnover mechanism discovered in this study will undoubtedly provide more rational and targeted ideas for future catalyst design.
查看更多>>摘要：The Li metal battery with ultrahigh-nickel cathode(LiNixM1-xO2,M=Mn,Co,and x ≥ 0.9)under high-voltage is regarded as one of the most promising approaches to fulfill the ambitious target of 400 Wh/kg.However,the practical application is impeded by the instability of electrode/electrolyte interface and Ni-rich cathode itself.Herein we proposed an electron-defect electrolyte additive trimethyl borate(TMB)which is paired with the commercial carbonate electrolyte to construct highly conductive fluorine-and boron-rich cathode electrolyte interface(CEI)on LiNi0.9Co0.05Mn0.05O2(NCM90)surface and solid electrolyte interphase(SEI)on lithium metal surface.The modified CEI effectively mitigates the structural transformation from layered to disordered rock-salt phase,and consequently alleviate the dissolution of transition metal ions(TMs)and its"cross-talk"effect,while the enhanced SEI enables stable lithium plat-ing/striping and thus demonstrated good compatibility between electrolyte and lithium metal anode.As a result,the common electrolyte with 1 wt％TMB enables 4.7 V NCM90/Li cell cycle stably over 100 cycles with 70％capacity retention.This work highlights the significance of the electron-defect boron com-pounds for designing desirable interfacial chemistries to achieve high performance NCM90/Li battery under high voltage operation.
查看更多>>摘要：Anticipating the imminent surge of retired lithium-ion batteries(R-LIBs)from electric vehicles,the need for safe,cost-effective and environmentally friendly disposal technologies has escalated.This paper seeks to offer a comprehensive overview of the entire disposal framework for R-LIBs,encompassing a broad spectrum of activities,including screening,repurposing and recycling.Firstly,we delve deeply into a thorough examination of current screening technologies,shifting the focus from a mere enumeration of screening methods to the exploration of the strategies for enhancing screening efficiency.Secondly,we outline battery repurposing with associated key factors,summarizing stationary applications and siz-ing methods for R-LIBs in their second life.A particular light is shed on available reconditioning solutions,demonstrating their great potential in facilitating battery safety and lifetime in repurposing scenarios and identifying their techno-economic issues.In the realm of battery recycling,we present an extensive sur-vey of pre-treatment options and subsequent material recovery technologies.Particularly,we introduce several global leading recyclers to illustrate their industrial processes and technical intricacies.Furthermore,relevant challenges and evolving trends are investigated in pursuit of a sustainable end-of-life management and disposal framework.We hope that this study can serve as a valuable resource for researchers,industry professionals and policymakers in this field,ultimately facilitating the adoption of proper disposal practices.
查看更多>>摘要：The electrochemical nitrogen reduction reaction(eNRR)holds significant promise as a sustainable alter-native to the conventional large-scale Haber Bosch process,offering a carbon footprint-free approach for ammonia synthesis.While the process is thermodynamically feasible at ambient temperature and pres-sure,challenges such as the competing hydrogen evolution reaction,low nitrogen solubility in elec-trolytes,and the activation of inert dinitrogen(N2)gas adversely affect the performance of ammonia production.These hurdles result in low Faradaic efficiency and low ammonia production rate,which pose obstacles to the commercialisation of the process.Researchers have been actively designing and propos-ing various electrocatalysts to address these issues,but challenges still need to be resolved.A key strategy in electrocatalyst design lies in understanding the underlying mechanisms that govern the success or fail-ure of the electrocatalyst in driving the electrochemical reaction.Through mechanistic studies,we gain valuable insights into the factors affecting the reaction,enabling us to propose optimised designs to over-come the barriers.This review aims to provide a comprehensive understanding of the various mecha-nisms involved in eNRR on the electrocatalyst surface.It delves into the various mechanisms such as dissociative,associative,Mars-van Krevelen,lithium-mediated nitrogen reduction and surface hydro-genation mechanisms of nitrogen reduction.By unravelling the intricacies of eNRR mechanisms and exploring promising avenues,we can pave the way for more efficient and commercially viable ammonia synthesis through this sustainable electrochemical process by designing an efficient electrocatalyst.
查看更多>>摘要：Constructing heterostructured nanohybrid is considered as a prominent route to fabricate alternative electrocatalysts to commercial Pt/C for hydrogen evolution reaction(HER).In this work,(NH4)4[NiH6Mo6O24]·5H2O polyoxometalates(NiMo6)are adopted as the cluster precursors for simple fabrication of heterostructured Pt-Ni3Mo3N nanohybrids supported by carbon black(Pt-Ni3Mo3N/C)without using additional N sources.The improved porosity and enhanced electronic interaction of Pt-Ni3Mo3N/C should be attributed to the integration of Pt with NiMo6,which favors the mass transport,promotes the formation of exposed catalytic sites,and benefits the regulation of intrinsic activity.Thus,the as-obtained Pt-Ni3Mo3N/C exhibits impressive and durable HER performance as indicated by the low overpotential of 13.7 mV at the current density of 10 mA cm-2 and the stable overpotential dur-ing continuous working at 100 mA cm-2 for 100 h.This work provides significant insights for the synthe-sis of new highly active heterostructured electrocatalysts for renewable energy devices.
查看更多>>摘要：Electrochemical reduction of CO2(CO2RR)has become a research hot spot in recent years in the context of carbon neutrality.HCOOH is one of the most promising products obtained by electrochemical reduction of CO2 due to its high energy value as estimated by market price per energy unit and wide application in chem-ical industry.Biomass is the most abundant renewable resource in the natural world.Coupling biomass oxidative conversion with CO2RR driven by renewable electricity would well achieve carbon negativity.In this work,we comprehensively reviewed the current research progress on CO2RR to produce HCOOH and coupled system for conversion of biomass and its derivatives to produce value-added products.Sn-and Bi-based electrocatalysts are discussed for CO2RR with regards to the structure of the catalyst and reac-tion mechanisms.Electro-oxidation reactions of biomass derived sugars,alcohols,furan aldehydes and even polymeric components of lignocellulose were reviewed as alternatives to replace oxygen evolution reaction(OER)in the conventional electrolysis process.It was recommended that to further improve the efficiency of the coupled system,future work should be focused on the development of more efficient and stable catalysts,careful design of the electrolytic cells for improving the mass transfer and development of environment-friendly processes for recovering the formed formate and biomass oxidation products.
查看更多>>摘要：Niobium pentoxide(Nb2O5)is deemed one of the promising anode materials for lithium-ion batteries(LIBs)for its outstanding intrinsic fast Li-(de)intercalation kinetics.The specific capacity,however,is still limited,because the(de)intercalation of excessive Li-ions brings the undesired stress to damage Nb2O5 crystals.To increase the capacity of Nb2O5 and alleviate the lattice distortion caused by stress,numerous homogeneous H-and M-phases junction interfaces were proposed to produce coercive stress within the Nb2O5 crystals.Such interfaces bring about rich oxygen vacancies with structural shrinkage tendency,which pre-generate coercive stress to resist the expansion stress caused by excessive Li-ions intercala-tion.Therefore,the synthesized Nb2O5 achieves the highest lithium storage capacity of 315 mA h g-1 to date,and exhibits high-rate performance(118 mA h g-1 at 20 C)as well as excellent cycling stability(138 mA h g-1 at 10 C after 600 cycles).
查看更多>>摘要：Lithium-ion batteries are widely recognized as a crucial enabling technology for the advancement of elec-tric vehicles and energy storage systems in the grid.The design of battery state estimation and control algorithms in battery management systems is usually based on battery models,which interpret crucial battery dynamics through the utilization of mathematical functions.Therefore,the investigation of bat-tery dynamics with the purpose of battery system identification has garnered considerable attention in the realm of battery research.Characterization methods in terms of linear and nonlinear response of lithium-ion batteries have emerged as a prominent area of study in this field.This review has undertaken an analysis and discussion of characterization methods,with a particular focus on the motivation of bat-tery system identification.Specifically,this work encompasses the incorporation of frequency domain nonlinear characterization methods and dynamics-based battery electrical models.The aim of this study is to establish a connection between the characterization and identification of battery systems for researchers and engineers specialized in the field of batteries,with the intention of promoting the advancement of efficient battery technology for real-world applications.
查看更多>>摘要：In the development of Li-ion batteries(LIBs)with high energy/power density,long cycle-life,fast charg-ing,and high safety,an insight into charge transfer reactions is required.Although electrochemical impe-dance spectroscopy(EIS)is regarded as a powerful diagnosis tool,it is not a direct but an indirect measurement.With respect to this,some critical questions need to be answered:(ⅰ)why EIS can reflect the kinetics of charge transfer reactions;(ⅱ)what the inherent logical relationship between impedance models under different physical scenes is;(ⅲ)how charge transfer reactions compete with each other at multiple scales.This work aims at answering these questions via developing a theory framework so as to mitigate the blindness and uncertainty in unveiling charge transfer reactions in LIBs.To systemat-ically answer the above questions,this article is organized into a three-in-one(review,tutorial,and research)type and the following contributions are made:(ⅰ)a brief review is given for impedance model development of the LIBs over the past half century;(ⅱ)an open source code toolbox is developed based on the unified impedance model;(ⅲ)the competive mechanisms of charge transfer reactions are unveiled based on the developed EIS-Toolbox@LIB.This work not only clarifies theoretical fundamentals,but also provides an easy-to-use open source code for EIS-Toolbox@LIB to optimize fast charge/discharge,mitigate cycle aging,and improve energy/power density.
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