Michael Ruby RajJungwon YunDong-kyu SonGibaek Lee...
199-226页
查看更多>>摘要：Graphitic carbon nitride(g-C3N4)is widely used in organic metal-ion batteries owing to its high porosity,facile synthesis,stability,and high-rate performance.However,pristine g-C3N4 nanosheets exhibit poor electrical conductivity,irreversible metal-ion storage capacity,and short-term cycling owing to their high concentration of graphitic-N species.Herein,a series of 3,4:9,10-perylenetetracarboxylic diimide-coupled g-C3N4 composite anode materials,CN-PIx(x=0.2,0.5,0.75,and 1),was investigated,which exhibited an unusually high surface nitrogen content(23.19-39.92 at.％)and the highest pyridinic-N,pyrrolic-N,and graphitic-N contents reported to date.The CN-PI1 anode delivers an unprecedented and continuously increasing ultrahigh discharging capacity of exceeding 8400 mAh g-1(1.96 mWh cm-2)at 100 mA g-1 with high specific energy density(Esp)of～7700 Wh kg-1 and the volumetric energy density(Ev)of～14956 Wh L-1 and an excellent long-term stability(414 mAh g-1 or 0.579 mWh cm-2 at 1 A g-1).Furthermore,the activation of the CN-PIx electrodes contributes to their superior electrochemical performance,resulting from the fact that the Li+is not only stored in the CN-PIx composites but also CN-PIx activated the Li0 adlayer on the CN-PI1-Cu heterojunction as an SEI layer to avoid the direct contact of Lio phase and the electrolyte.The CN-PI1 full cell with LiCoO2 as the cathode delivers a discharge capacity of～587 mAh g-1 at a 1 A g-1 after 250 cycles with a Coulombic efficiency nearly 99％.This study provides a strategy to develop N-doped g-C3N4-based anode materials for realizing long-lasting energy storage devices.
查看更多>>摘要：Low electronic conductivity and large volume changes during the(de)lithiation process are the two main challenges for ZnO anode materials used for lithium-ion batteries(LIB).Here,a free-standing,flexible,and binder-free LIB electrode composed of ZnO nanorods and carbon cloth(CC)is fabricated.This is then decorated with Ag nanoparticles and finally coated by an amorphous carbon layer to form the hybrid electrode:(C@(Ag&ZnO)).The voids among the nanorods are sufficient to accommodate the volume expansion of the ZnO while the flexible CC,which acts as the current collector,relieves the volume change-induced stress.The Ag nanoparticles are effective in improving the conductivity.This composite electrode shows excellent LIB performance with a stable long cycling life over 500 cycles with a reversible capacity of 1093 mAh g-1 at a current density of 200 mA g-1.It also shows good rate performance with reversible capacity of 517 mAh g-1 under a high-current density of 5000 mA g-1.In situ Raman spectroscopy is conducted to investigate the contributions of the amorphous carbon layer to the capacity of the whole electrode and the synergy between the CC and ZnO nanorods.
查看更多>>摘要：Ionic selectivity is of significant importance in both fundamental science and practical applications.For instance,an ion-selective material allows the passage of a particular kind of ions while blocking the others,which could be used for purification of materials.Herein,the Li-ion-selectivity of a garnet-type solid electrolyte is discussed by comparing the difference of activation energy between different ions migrating in solids.The high ion-selectivity is confirmed by harvesting high-purity metallic lithium(99.98 wt％)from low-lithium-purity sources(80 wt％)at a moderate temperature(190 ℃).This gives it huge potential in separating lithium with impurities especially alkali and alkali-earth elements.The cost of metallic lithium production is only 25％of the international lithium price.The proposed electrochemical metallic lithium separating method is advantageous compared with the traditional process in terms of efficiency,safety,and cost.
查看更多>>摘要：The commercialization of electrolytic MnO2-Zn batteries is highly applauded owing to the advantages of cost-effectiveness,high safety,high energy density,and durable working performance.However,due to the low reversibility of the cathode MnO2/Mn2+chemistry at high areal capacities and the severe Zn anode corrosion,the practical application of MnO2-Zn batteries is hampered by inadequate lifespan.Leveraging the full advantage of an iodine redox mediator,here we design a highly rechargeable electrolytic MnO2-Zn battery with a high areal capacity.The MnO2-Zn battery coupled with an iodine mediator in a mild electrolyte shows a high discharge voltage of 1.85 V and a robust areal capacity of 10 mAh cm-2 under a substantial discharge current density of 160 mA cm-2.The MnO2/l2-Zn battery with an areal capacity of 10 mAh cm-2 exhibits prolonged stability of over 950 cycles under a high-capacity retention of～94％.The scaled-up MnO2/I2-Zn battery reveals a stable cycle life under a cell capacity of～600 mAh.Moreover,our constructed MnO2/l2-Zn battery demonstrates a practical energy density of～37 Wh kg-1 and a competitive energy cost of＜18 US$ kWh-1 by taking into account the cathode,anode,and electrolyte.The MnO2/I2-Zn battery,with its remarkable reversibility and reasonable energy density,enlightens a new arena of large-scale energy storage devices.
查看更多>>摘要：MXene quantum dots(MQDs)offer wide applications owing to the abundant surface chemistry,tunable energy-level structure,and unique properties.However,the application of MQDs in electrochemical energy conversion,including hydrogen evolution reaction(HER),remains to be realized,as it remains a challenge to precisely control the types of surface groups and tune the structure of energy levels in MQDs,owing to the high surface energy-induced strong agglomeration in post-processing.Consequently,the determination of the exact catalytically active sites and processes involved in such an electrocatalysis is challenging because of the complexity of the synthetic process and reaction conditions.Herein,we demonstrated the spontaneous evolution of the surface groups of the Ti2CTx MQDs(x:the content of O atom),i.e.,replacement of the-Cl functional groups by O-terminated ones during the cathode reaction.This process resulted in a low Gibbs free energy(0.26 eV)in HER.Our steady Ti2COx/Cu2O/Cu foam systems exhibited a low overpotential of 175 mV at 10 mA cm-2 in 1 M aq.KOH,and excellent operational stability over 165 h at a constant current density of-10 mA cm-2.
查看更多>>摘要：Development of advanced high-voltage electrolytes is key to achieving high-energy-density lithium metal batteries(LMBs).Weakly solvating electrolytes(WSE)can produce unique anion-driven interphasial chemistry via altering the solvating power of the solvent,but it is difficult to dissolve the majority of Li salts and fail to cycle at a cut-off voltage above 4.5 V.Herein,we present a new-type WSE that is regulated by the anion rather than the solvent,and the first realize stable cycling of dimethoxyethane(DME)at 4.6 V without the use of the"solvent-in-salt"strategy.The relationships between the degree of dissociation of salts,the solvation structure of electrolytes,and the electrochemical performance of LMBs were systematically investigated.We found that LiBF4,which has the lowest degree of dissociation,can construct an anion-rich inner solvation shell,resulting in anion-derived anode/cathode interphases.Thanks to such unusual solvation structure and interphasial chemistry,the Li-LiCoO2 full cell with LiBF4-based WSE could deliver excellent rate performance(115 mAh g-1 at 10 C)and outstanding cycling stability even under practical conditions,including high loading(10.7 mg cm-2),thin Li(50 pm),and limited electrolyte(1.2 μL mg1).
查看更多>>摘要：With rapid progress,organic solar cells(OSCs)are getting closer to the target of real application.However,the stability issue is still one of the biggest challenges that have to be resolved.Especially,the thermal stability of OSCs is far from meeting the requirements of the application.Here,based on the layer-by-layer(LBL)process and by utilizing the dissolubility nature of solvent and materials,binary inverted OSCs(ITO/AZO/PM6/BTP-eC9/MoO3/Ag)with comb shape active morphology are fabricated.High efficiency of 17.13％and simultaneous superior thermal stability(with 93％of initial efficiency retained in～9:00 h under 85 ℃ in N2)are demonstrated,showing superior stability to reference cells.The enhancements are attributed to the formed optimal comb shape of the active layer,which could provide a larger D/A interface,thus more charge carriers,render the active blend a more stable morphology,and protect the electrode by impeding ion's migration and corrosion.To the best of our knowledge,this is the best thermal stability of binary OSCs reported in the literature,especially when considering the high efficiency of over 17％.
Ishamol ShajiDiddo DiddensMartin WinterJijeesh Ravi Nair...
273-282页
查看更多>>摘要：The solvent-free in situ polymerization technique has the potential to tailor-make conformal interfaces that are essential for developing durable and safe lithium metal polymer batteries(LMPBs).Hence,much attention has been given to the eco-friendly and rapid ultraviolet(UV)-induced in situ photopolymerization process to prepare solid-state polymer electrolytes.In this respect,an innovative method is proposed here to overcome the challenges of UV-induced photopolymerization(UV-curing)in the zones where UV-light cannot penetrate,especially in LMPBs where thick electrodes are used.The proposed frontal-inspired photopolymerization(FIPP)process is a diverged frontal-based technique that uses two classes(dual)of initiators to improve the slow reaction kinetics of allyl-based monomers/oligomers by at least 50％compared with the conventional UV-curing process.The possible reaction mechanism occurring in FIPP is demonstrated using density functional theory calculations and spectroscopic investigations.Indeed,the initiation mechanism identified for the FIPP relies on a photochemical pathway rather than an exothermic propagating front forms during the UV-irradiation step as the case with the classical frontal photopolymerization technique.Besides,the FIPP-based in situ cell fabrication using dual initiators is advantageous over both the sandwich cell assembly and conventional in situ photopolymerization in overcoming the limitations of mass transport and active material utilization in high energy and high power LMPBs that use thick electrodes.Furthermore,the LMPB cells fabricated using the in situ-FIPP process with high mass loading LiFePO4 electrodes(5.2 mg cm-2)demonstrate higher rate capability,and a 50％increase in specific capacity against a sandwich cell encouraging the use of this innovative process in large-scale solid-state battery production.
查看更多>>摘要：Organosulfur materials are a sustainable alternative to the present-day layered oxide cathodes in lithium-based batteries.One such organosulfur material that was intensely explored from the 1990s to early 2010s is 2,5-dimercapto-1,3,4-thiadiazole(DMCT).However,research interest declined as the electrode reactions with DMCT were assumed to be too sluggish to be practical.Armed with the advances in metal-sulfur batteries,we revisit DMCT-based materials in the form of poly[tetrathio-2,5-(1,3,4-thiadiazole)],referred to as pDMCT-S.With an appropriate choice of electrode design and electrolyte,pDMCT-S cathode paired with a Li-metal anode shows a capacity of 715 mA h g-1 and a Coulombic efficiency of 97.7％at a C/10 rate,thus quelling the concerns of sluggish reactions.Surprisingly,pDMCT-S shows significantly improved long-term cyclability compared to a sulfur cathode.Investigations into the origin of the stability reveals that the discharge product Li-DMCT in its mesomeric form can strongly bind to polysulfides,preventing their dissolution into the electrolyte and shuttling.This unique mechanism solves a critical problem faced by sulfur cathodes.Encouragingly,this mechanism results in a stable performance of pDMCT-S with Na-metal cells as well.This study opens the potential for exploring other organic materials that have inherent polysulfide sequestering capabilities,enabling long-life metal-sulfur batteries.
查看更多>>摘要：With the rapid development of flexible and portable microelectronics,the extreme demand for miniaturized,mechanically flexible,and integrated microsystems are strongly stimulated.Here,biomass-derived carbons(BDCs)are prepared by KOH activation using Qamgur precursor,exhibiting three-dimensional(3D)hierarchical porous structure.Benefiting from unobstructed 3D hierarchical porous structure,BDCs provide an excellent specific capacitance of 433 F g1 and prominent cyclability without capacitance degradation after 50 000 cycles at 50 A g1.Furthermore,BDC-based planar micro-supercapacitors(MSCs)without metal collector,prepared by mask-assisted coating,exhibit outstanding areal-specific capacitance of 84 mF cm-2 and areal energy density of 10.6 pWh cm-2,exceeding most of the previous carbon-based MSCs.Impressively,the MSCs disclose extraordinary flexibility with capacitance retention of almost 100％under extreme bending state.More importantly,a flexible planar integrated system composed of the MSC and temperature sensor is assembled to efficiently monitor the temperature variation,providing a feasible route for flexible MSC-based functional micro-devices.
NETL
NSTL
万方数据