查看更多>>摘要：Challenges facing high-voltage/high-capacity cathodes,in addition to the longstanding problems pertinent to lithium(Li)-metal anodes,should be addressed to develop high-energy-density Li-metal batteries.This issue mostly stems from interfacial instability between electrodes and electrolytes.Conventional carbonate-or ether-based liquid electrolytes suffer from not only volatility and flammability but also limited electrochemical stability window.Here,we report a nitrile electrolyte strategy based on concentrated nitrile electrolytes(CNEs)with co-additives.The CNE consists of high-concentration lithium bis(fluorosulfonyl)imide(LiFSI)in a solvent mixture of succinonitrile(SN)/acetonitrile(AN).The SN/AN solvent mixture is designed to ensure high oxidation stability along with thermal stability,which are prerequisites for high-voltage Li-metal cells.The CNE exhibits interfacial stability with Li metals due to the coordinated solvation structure.Lithium nitrate(LiNO3)and indium fluoride(lnF3)are incorporated in the CNE as synergistic co-additives to further stabilize solid-electrolyte interphase(SEI)on Li metals.The resulting electrolyte(CNE+LiNO3/lnF3)enables stable cycling performance in LillLiNi0.8Co0.1Mn0.1 and 4.9 V-class LillLiNi0.5Mn1.5O4 cells.Notably,the LillLiNi0.5Mn1.5O4 cell maintains its electrochemical activity at high temperature(100 ℃)and even in flame without fire or explosion.
查看更多>>摘要：It remains challenging to effectively estimate the remaining capacity of the secondary lithium-ion batteries that have been widely adopted for consumer electronics,energy storage,and electric vehicles.Herein,by integrating regular real-time current short pulse tests with data-driven Gaussian process regression algorithm,an efficient battery estimation has been successfully developed and validated for batteries with capacity ranging from 100％of the state of health(SOH)to below 50％,reaching an average accuracy as high as 95％.Interestingly,the proposed pulse test strategy for battery capacity measurement could reduce test time by more than 80％compared with regular long charge/discharge tests.The short-term features of the current pulse test were selected for an optimal training process.Data at different voltage stages and state of charge(SOC)are collected and explored to find the most suitable estimation model.In particular,we explore the validity of five different machine-learning methods for estimating capacity driven by pulse features,whereas Gaussian process regression with Matern kernel performs the best,providing guidance for future exploration.The new strategy of combining short pulse tests with machine-learning algorithms could further open window for efficiently forecasting lithium-ion battery remaining capacity.
查看更多>>摘要：The uncontrollable Li electrostripping and plating process that results in dendritic Li growth and huge volume change of Li anode limits the practicality of Li metal batteries(LMBs).To simultaneously address these issues,designing three-dimensional(3D),lithiophilic and mechanically robust electrodes seems to be one of the cost-effective strategies.Herein,a new 3D Li-B-C-Al alloy anode is designed and fabricated.The prepared 3D alloy anode exhibits not only superior lithiophilicity that facilitates uniform Li nucleation and growth but also sufficient mechanical stability that maintains its structural integrity.Superior performance of the prepared 3D alloy is demonstrated through comprehensive electrochemical tests.In addition,non-destructive and 3D synchrotron X-ray computed tomography(SX-CT)technique is employed to investigate the underlying working mechanisms of the prepared alloy anode.A unique twofold Li electrostripping and plating mechanism under different electrochemical cycling conditions is revealed.Lastly,improved performance of the full cells built with the 3D alloy anode and LiNi0.8Co0.1Mn0.1O2(NCM811)cathode corroborate its potential application capability.Overall,the current work not only showcases the superiority of the 3D alloy as potential anode material for LMBs but also provides fundamental insights into its underlying working mechanisms that may further propel its research and development.
查看更多>>摘要：All inorganic CsPbl3 perovskite solar cells(PSCs)have emerged as disruptive photovoltaic technology owing to their admirable photoelectric properties and the non-volatile active layer.However,the phase instability against moisture severely limits the fabrication environment for the high-efficiency devices,breaking through the confinement region to achieve scalable manufacturing has been the primary issue for future commercialization.Here,we develop a curing-anti-solvent strategy for fabricating high-quality and stable black-phase CsPbl3 perovskite films in ambient air by introducing an inorganic polymer perhydropolysilazane(PHPS)into methyl acetate to form anti-template agent.The cross-linked PHPS reduces moisture erosions while the hydrolyzate silanol network(-Si(OH)4-)controls the perovskite crystal growth by forming Lewis adducts with Pbl2 during the fabrication.The polycondensation adduct of Si-O-Si/Si-O-Pb strongly binds to CsPbl3 grains as a shield layer to hamper phase transition.Using the inorganic CsPbl3 perovskite thin-film with PHPS-modified anti-solvent processing as the light absorber,the n-i-p planar solar cell achieved an efficiency of 19.17％under standard illumination test conditions.More importantly,the devices showed excellent moisture stability,retaining about 90％of the initial efficiency after 1000 h under 30％RH.
查看更多>>摘要：Developing efficient oxygen reduction reaction(ORR)catalyst is essential for the practical application of Zn-air batteries(ZABs).In this contribution,we develop a novel zeolitic imidazolate framework(ZIF)-mediated strategy to anchor Co species on N-doped carbon nanorods for efficient ORR.Featuring ultrahigh N-doping(10.29 at.％),monodisperse Co nanocrystal decoration,and well-dispersed Co-Nx functionalization,the obtained Co-decorated N-doped carbon nanorods(Co@NCNR)exhibit a decent ORR performance comparable to commercial Pt/C in alkaline media.Aqueous ZABs have been assembled using Co@NCNR as the cathode catalyst.The assembled ZABs manifest high initial open-circuit voltage as well as high energy density.In addition,the Co@NCNR also demonstrates ideal ORR performance in quasi-solid-state ZABs.
查看更多>>摘要：The main bottleneck against industrial utilization of sodium ion batteries(SIBs)is the lack of high-capacity electrodes to rival those of the benchmark lithium ion batteries(LIBs).Here in this work,we have developed an economical method for in situ fabrication of nanocomposites made of crystalline few-layer graphene sheets loaded with ultrafine SnO2 nanocrystals,using short exposure of microwave to xerogel of graphene oxide(GO)and tin tetrachloride containing minute catalyzing dispersoids of chemically reduced GO(RGO).The resultant nanocomposites(SnO2@MWG)enabled significantly quickened redox processes as SIB anode,which led to remarkable full anode-specific capacity reaching 538 mAh g-1 at 0.05 A g-1(about 1.45 times of the theoretical capacity of graphite for the LIB),in addition to outstanding rate performance over prolonged charge-discharge cycling.Anodes based on the optimized SnO2@MWG delivered stable performance over 2000 cycles even at a high current density of 5 A g-1,and capacity retention of over 70.4％was maintained at a high areal loading of 3.4 mg cm-2,highly desirable for high energy density SIBs to rival the current benchmark LIBs.
查看更多>>摘要：Attributing to the high specific capacity and low electrochemical reduction potential,lithium(Li)metal is regarded as the most promising anode for high-energy Li batteries.However,the growth of lithium dendrites and huge volume change seriously limit the development of lithium metal batteries.To overcome these challenges,an ordered mesoporous N-doped carbon with lithiophilic single atoms is proposed to induce uniform nucleation and deposition of Li metal.Benefiting from the synergistic effects of interconnected three-dimensional ordered mesoporous structures and abundant lithiophilic single-atom sites,regulated local current density and rapid mass transfer can be achieved,leading to the uniform Li deposition with inhibition of dendrites and buffered volume expansion.As a result,the as-fabricated anode exhibits a high CE of 99.8％for 200 cycles.A stable voltage hysteresis of 14 mV at 5 mA cm-2 could be maintained for more than 1330 h in the symmetric cell.Furthermore,the full cell coupled with commercial LiFePO4 exhibits high reversible capacity of 108 mAh g-1 and average Coulombic efficiency of 99.8％from 5th to 350th cycles at 1 C.The ordered mesoporous carbon host with abundant lithiophilic single-atom sites delivers new inspirations into rational design of high-performance Li metal anodes.
查看更多>>摘要：Li metal with high-energy density is considered as the most promising anode for the next-generation rechargeable Li metal batteries;however,the growth of Li dendrites seriously hinders its practical application.Herein,3D free-standing carbon nanofibers modified by lithiophilic metal particles(CNF/Me,Me=Sn,Fe,Co)are obtained in situ by the electrospinning method.Benefiting from the lithophilicity,the CNF/Me composite may effectively prevent the formation of Li dendrites in the Li metal batteries.The optimized CNF/Sn-Li composite electrode exhibits a stable cycle life of over 2350 h during Li plating/stripping.When matched with typical commercial LiFePO4(LFP)cathode,the LFP//CNF/Sn-Li full cell presents a high initial discharge specific capacity of 139 mAh g-1 at 1 C,which remains at 146 mAh g-1 after 400 cycles.When another state-of-the-art commercial LiNi0.8Co0.1Mn0.1O2(NCM(811))cathode is used,the assembled NCM//CNF/Sn-Li full cell shows a large initial specific discharge capacity of 206 mAh g-1 at substantially enhanced 10 C,which keeps at the good capacity of 99 mAh g-1 after 300 cycles.These results are greatly superior to the counterparts with Li as the anodes,indicating the great potential for practical utilization of the advanced CNF/Sn-Li electrode.
Kejun ChenEnrico NapolitaniMatteo De TullioChun-Sheng Jiang...
397-408页
查看更多>>摘要：Polycrystalline Si(poly-Si)-based passivating contacts are promising candidates for high-efficiency crystalline Si solar cells.We show that nanosecond-scale pulsed laser melting(PLM)is an industrially viable technique to fabricate such contacts with precisely controlled dopant concentration profiles that exceed the solid solubility limit.We demonstrate that conventionally doped,hole-selective poly-Si/SiOx contacts that provide poor surface passivation of c-Si can be replaced with Ga-or B-doped contacts based on non-equilibrium doping.We overcome the solid solubility limit for both dopants in poly-Si by rapid cooling and recrystallization over a timescale of～25 ns.We show an active Ga dopant concentration of～3 X 1020 cm-3 in poly-Si which is six times higher than its solubility limit in c-Si,and a B dopant concentration as high as～1021 cm-3.We measure an implied open-circuit voltage of 735 mV for Ga-doped poly-Si/SiOx contacts on Czochralski Si with a low contact resistivity of 35.5±2.4 mΩ cm2.Scanning spreading resistance microscopy and Kelvin probe force microscopy show large diffusion and drift current in the p-n junction that contributes to the low contact resistivity.Our results suggest that PLM can be extended for hyperdoping of other semiconductors with low solubility atoms to enable high-efficiency devices.
查看更多>>摘要：The use of heterojunctions is a promising solution to the problem of cross-sensitivity in gas sensors.In this work,a carbon monoxide sensor based on the CuO/TiO2 heterojunction was designed and fabricated.Due to the good adsorption properties of CuO materials to CO,and the heterojunction interface charge transfer,the CuO/TiO2 thin film sensor exhibits high sensitivity to CO at room temperature.The response is as high as 10.8-200 ppm CO,about 10 times its response to H2.Interference from H2 is greatly reduced by optimizing the structure of the CuO/TiO2 heterojunction.This reliable detection of carbon monoxide with excellent discrimination against H2 is of great significance for the development of CO gas sensors.
维普
万方数据