LiMnOand LiNiAlyMnO（x= 0.50;y = 0.05-0.50） powders have been synthesized via facile solgel method using Behenic acid as active cheiating agent.The synthesized samples are subjected to physical characterizations such...LiMnOand LiNiAlyMnO（x= 0.50;y = 0.05-0.50） powders have been synthesized via facile solgel method using Behenic acid as active cheiating agent.The synthesized samples are subjected to physical characterizations such as thermo gravimetric analysis（TG/DTA）,X-ray diffraction（XRD）,Fourier transform infrared spectroscopy（FT-IR）,field-emission scanning electron microscopy（FESEM）,transmission electron microscopy（TEM） and electrochemical studies viz.,galvanostatic cycling properties,electrochemical impedance spectroscopy（EIS） and differential capacity curves（dQ/dE）.Finger print XRD patterns of LiMnOand LiNiAlMnOfortify the high degree of crystallinity with better phase purity.FESEM images of the undoped pristine spinel illustrate uniform spherical grains surface morphology with an average particle size of 0.5 μm while Ni doped particles depict the spherical grains growth（50nm） with ice-cube surface morphology.TEM images of the spinel LiMnOshows the uniform spherical morphology with particle size of（100 nm） while low level of Al-doping spinel（LiNio.5Alo.05Mn1.45O4） displaying cloudy particles with agglomerated particles of（50nm）.The LiMnOsamples calcined at 850℃ deliver the discharge capacity of 130 mAh/g in the first cycle corresponds to 94%coiumbic efficiency with capacity fade of 1.5 mAh/g/cycle over the investigated 10 cycles.Among all four dopant compositions investigated,LiNiAlMnOdelivers the maximum discharge capacity of 126 mAh/g during the first cycle and shows the stable cycling performance with low capacity fade of 1 mAh/g/cycle（capacity retention of 92%） over the investigated 10 cycles.Electrochemical impedance studies of spinel LiMnOand LiNiAlMnOdepict the high and low real polarization of 1562 and 1100 Ω.展开更多
Spinel LiNi_(0.5)Mn_(1.5)O_(4)(LNMO),a 5 V class high voltage cathode,has been regarded as an attractive candidate to further improve the energy density of lithium-ion battery.The issue simultaneously enabling side st...Spinel LiNi_(0.5)Mn_(1.5)O_(4)(LNMO),a 5 V class high voltage cathode,has been regarded as an attractive candidate to further improve the energy density of lithium-ion battery.The issue simultaneously enabling side stability and maintaining high interfacial kinetics,however,has not yet been resolved.Herein,we design a coherent Li_(1.3)A_(l0.3)Ti_(1.7)(PO)_(4)(LATP)layer that is crystally connected to the spinel LNMO host lattices,which offers fast lithium ions transportation as well as enhances the mechanical stability that prevents the particle fracture.Furthermore,the inactive Li_(3)BO_(3)(LBO)coating layer inhibits the corrosion of transition metals and continuous side reactions.Consequently,the coherent-engineered LNMO-LATPLBO cathode material exhibits superior electrochemical cycling stability in a window of 3.0–5.0 V,for example a high-capacity retention that is 89.7%after 500 cycles at 200 m A g-1obtained and enhanced rate performance(85.1 m A h g^(-1)at 800 m A g^(-1))when tested with a LiPF6-based carbonate electrolyte.Our work presents a new approach of engineering 5 V class spinel oxide cathode that combines interfacial coherent crystal lattice design and surface coating.展开更多
LiMn<sub>2</sub>O<sub>4</sub> and LiCu<sub>x</sub>Cr<sub>y</sub>Mn<sub>2-x-y</sub>O<sub>4</sub> (x = 0.50;y = 0.05 - 0.50) powders have been synt...LiMn<sub>2</sub>O<sub>4</sub> and LiCu<sub>x</sub>Cr<sub>y</sub>Mn<sub>2-x-y</sub>O<sub>4</sub> (x = 0.50;y = 0.05 - 0.50) powders have been synthesized via sol-gel method for the first time using Myristic acid as chelating agent. The synthesized samples have been taken to physical and electrochemical characterization such as thermo gravimetric analysis (TG/DTA), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and electrochemical characterization viz., electrochemical galvanostatic cycling studies, electrochemical impedance spectroscopy (EIS) and differential capacity curves (dQ/dE). XRD patterns of LiMn<sub>2</sub>O<sub>4</sub> and LiCu<sub>x</sub>Cr<sub>y</sub>Mn<sub>2-x-y</sub>O<sub>4</sub> confirm high degree of crystallinity with good phase purity. FESEM image of undoped pristine spinel lucidly depicts cauliflower morphology with good agglomerated particle size of 50 nm while 0.5-Cu doped samples depict the pebbles morphology. TEM images of the spinel LiMn<sub>2</sub>O<sub>4</sub> and LiCu<sub>0.5</sub>Cr<sub>0.05</sub>Mn<sub>1.45</sub>O<sub>4</sub> authenticate that all the synthesized particles via sol-gel method are nano-sized (100 nm) with spherical surface and cloudy particles morphology. The LiMn<sub>2</sub>O<sub>4</sub> samples calcined at 850℃ deliver the high discharge capacity of 130 mA·h/g with cathodic efficiency of 88% corresponds to 94% columbic efficiency in the first cycle. Among all four compositions studied, LiCu<sub>0.5</sub>Cr<sub>0.05</sub>Mn<sub>1.45</sub>O<sub>4</sub> delivers 124 mA·h/g during the first cycle and shows stable performance with a low capacity fade of 1.1 mA·h/g cycle over the investigated 10 cycles.展开更多
LiMn2O4 powder as a cathode materials for rechargeable lithium-ion batteries was prepared by solid-state reaction from LitCO3 and electrolytic MnOz at different sintering periods （2, 6, 18, and 32 h）. X-ray diffract...LiMn2O4 powder as a cathode materials for rechargeable lithium-ion batteries was prepared by solid-state reaction from LitCO3 and electrolytic MnOz at different sintering periods （2, 6, 18, and 32 h）. X-ray diffraction （XRD） patterns of the prepared samples are identified as the spinel structure with a space group of Fd3 m. The lattice parameters almost remain the same as the sintering periods increase. The sample with a sintering period of 32 h shows good cycling performance at both low and nigh current densities, and also elevated temperature. It is believed that the excellent electrochemical behavior of this sample results from its good crystallinity and large grain size compared with other samples. Different electrochemical measurements were conducted to investigate the electrochemical properties of spinel LiMn204. 2008 University of Science and Technology Beijing. All rights reserved.展开更多
Multi-doped spinels, namely LiMn204 and LiZnxHoyMn2 x yO4 （x=0.10-0.18; y= 0.02-0.10）, for use as cathode materials for lithium-ion rechargeable batteries were synthesized via sol-gel method, using lauric acid as th...Multi-doped spinels, namely LiMn204 and LiZnxHoyMn2 x yO4 （x=0.10-0.18; y= 0.02-0.10）, for use as cathode materials for lithium-ion rechargeable batteries were synthesized via sol-gel method, using lauric acid as the chelating agent, to obtain micron-sized particles. The physical properties of the synthesized samples were investigated using differential thermal analysis, Fourier-transform infrared spectroscopy, X-ray diffraction （XRD）, scanning electron microscopy （SEM）, transmission electron microscopy, energy-dispersive X-ray analysis, and electrochemical methods. XRD showed that LiMn204 and LiZnxHoyMn2_x y04 have high degrees of crystallinity and good phase purities. The SEM images of LiMn204 showed an ice-cube morphology with particles of size 1 μm. Charge-discharge studies showed that undoped LiMn2 O4 delivered the discharge capacity of 124 mA h/g with coulombic efficiency of 95% during the first cycle, whereas doped spinels delivered discharge capacities of 125, 120, and 127 mA h/g in the first cycle with coulombic efficiencies of 96%, 91%, and 91%, respectively.展开更多
Hierarchical yolk-shell structured cathodes with controllable composition are potentially attractive materials for the fabrication of lithium-ion batteries, but they are difficult to synthesize. In this work, we prese...Hierarchical yolk-shell structured cathodes with controllable composition are potentially attractive materials for the fabrication of lithium-ion batteries, but they are difficult to synthesize. In this work, we present a simple, scalable, and general morphology-inheritance strategy to synthesize spinel manganese cathodes with a hierarchical yolk-shell structure. Starting from uniform Mn carbonate spheres prepared by an ultrafast and scalable microwave-assisted method, we show that the subsequent sintering results in the formation of Mn203 precursors with a yolk-shell structure, which can be effectively transferred to spinel manganese cathodes via simple impregnation and solid-state reaction. Owing to the simple and scalable nature of the present strategy, materials prepared through this approach have great potential as cathodes of lithium-ion batteries, where they can lead to high specific capacity, outstanding cyclability, and superior rate capability. In particular, both LiMn204 and LiNi05Mn1504 with hierarchical yolk-shell structure achieved nearly theoretical capacity, without any apparent decay after 100 cycles at I C. Moreover, 80% of the initial discharge capacities of both samples can be maintained for up to 500 cycles at a high rate of 10 C.展开更多
Spinel LiMn_(2)O_(4)(LMO)is deemed to be a promising cathode material for commercial lithium-ion batteries(LIBs)in prospect of its cost-effectiveness,nontoxicity,fabulous rate capability,and high energy density.Nevert...Spinel LiMn_(2)O_(4)(LMO)is deemed to be a promising cathode material for commercial lithium-ion batteries(LIBs)in prospect of its cost-effectiveness,nontoxicity,fabulous rate capability,and high energy density.Nevertheless,the LMO is inevitably confronted with sluggish diffusion kinetics and drastic capacity degradation triggered by multiple issues,including Jahn-Teller distortion,Mn dissolution,and structural attenuation.Thereinto,a metal-organic framework(MOF)chemistry engineering for hierarchical micro-/nano-structural F,O-dual-doped carbon embedded oxygen vacancy enriched LiMn_(2)O_(4)cathode(OV-LMO@FOC)is proposed for longevous LIBs.Bestowed by experimental and theoretical implementations,systematic investigations of OV-LMO@FOC endow that the meticulous integration of F,O-dual-doped carbon and oxygen vacancy in LMO-based cathode reconfigures the electronic structure,boosts electronic conductivity,expedites diffusion capability,facilitates energetically preferable Li^(+) adsorption,and suppresses Mn dissolution in the electrolyte,consequently achieving fabulous long-term cycling stability.As expected,the OV-LMO@FOC behaves with compelling electrochemical performance with prosperous reversible capacity(130.2 mAh g^(−1)at 0.2 C upon 200 cycles),exceptional rate capacity(93.7 mAh g^(−1) even at 20 C),and pronounced long-term cyclability(112.5 mAh g^(−1)after 1200 cycles with 77.6%capacity retention at 1 C).Even at the ultrahigh current density of 5 C,the OV-LMO@FOC bears a brilliant capacity of 96.9 mAh g^(−1)upon 1000 cycles with an extraordinary capacity retention of 90.7%,and maintains a discharge capacity of 70.9 mAh g^(−1)upon 4000 cycles.This work envisions the MOF-chemistry in surface modification and electronic modulation engineering of high-performance cathode materials towards industrialization in automotive market.展开更多
基金support given under the "Brain Pool Program of the Korean Federation of Science and Technology Societies" (KOFST), Republic of South Koreasupported by the Human Resources Development Program (No. 20124010203270) of the Korea Institute of Energy Technology EvaluationPlanning (KETEP) grant funded by the Korea Government Ministry of Trade, Industry and Energy
文摘LiMnOand LiNiAlyMnO（x= 0.50;y = 0.05-0.50） powders have been synthesized via facile solgel method using Behenic acid as active cheiating agent.The synthesized samples are subjected to physical characterizations such as thermo gravimetric analysis（TG/DTA）,X-ray diffraction（XRD）,Fourier transform infrared spectroscopy（FT-IR）,field-emission scanning electron microscopy（FESEM）,transmission electron microscopy（TEM） and electrochemical studies viz.,galvanostatic cycling properties,electrochemical impedance spectroscopy（EIS） and differential capacity curves（dQ/dE）.Finger print XRD patterns of LiMnOand LiNiAlMnOfortify the high degree of crystallinity with better phase purity.FESEM images of the undoped pristine spinel illustrate uniform spherical grains surface morphology with an average particle size of 0.5 μm while Ni doped particles depict the spherical grains growth（50nm） with ice-cube surface morphology.TEM images of the spinel LiMnOshows the uniform spherical morphology with particle size of（100 nm） while low level of Al-doping spinel（LiNio.5Alo.05Mn1.45O4） displaying cloudy particles with agglomerated particles of（50nm）.The LiMnOsamples calcined at 850℃ deliver the discharge capacity of 130 mAh/g in the first cycle corresponds to 94%coiumbic efficiency with capacity fade of 1.5 mAh/g/cycle over the investigated 10 cycles.Among all four dopant compositions investigated,LiNiAlMnOdelivers the maximum discharge capacity of 126 mAh/g during the first cycle and shows the stable cycling performance with low capacity fade of 1 mAh/g/cycle（capacity retention of 92%） over the investigated 10 cycles.Electrochemical impedance studies of spinel LiMnOand LiNiAlMnOdepict the high and low real polarization of 1562 and 1100 Ω.
基金supported by the Natural Science Foundation of Jiangsu Province(BK20200800)the National Natural Science Foundation of China(22209075,51902165,12004145)+1 种基金the Natural Science Foundation of Jiangxi Province(20212BAB214032,20192ACBL20048)the Key Science and Technology Plan Project of Ji’an City(20211-015311)。
文摘Spinel LiNi_(0.5)Mn_(1.5)O_(4)(LNMO),a 5 V class high voltage cathode,has been regarded as an attractive candidate to further improve the energy density of lithium-ion battery.The issue simultaneously enabling side stability and maintaining high interfacial kinetics,however,has not yet been resolved.Herein,we design a coherent Li_(1.3)A_(l0.3)Ti_(1.7)(PO)_(4)(LATP)layer that is crystally connected to the spinel LNMO host lattices,which offers fast lithium ions transportation as well as enhances the mechanical stability that prevents the particle fracture.Furthermore,the inactive Li_(3)BO_(3)(LBO)coating layer inhibits the corrosion of transition metals and continuous side reactions.Consequently,the coherent-engineered LNMO-LATPLBO cathode material exhibits superior electrochemical cycling stability in a window of 3.0–5.0 V,for example a high-capacity retention that is 89.7%after 500 cycles at 200 m A g-1obtained and enhanced rate performance(85.1 m A h g^(-1)at 800 m A g^(-1))when tested with a LiPF6-based carbonate electrolyte.Our work presents a new approach of engineering 5 V class spinel oxide cathode that combines interfacial coherent crystal lattice design and surface coating.
文摘LiMn<sub>2</sub>O<sub>4</sub> and LiCu<sub>x</sub>Cr<sub>y</sub>Mn<sub>2-x-y</sub>O<sub>4</sub> (x = 0.50;y = 0.05 - 0.50) powders have been synthesized via sol-gel method for the first time using Myristic acid as chelating agent. The synthesized samples have been taken to physical and electrochemical characterization such as thermo gravimetric analysis (TG/DTA), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and electrochemical characterization viz., electrochemical galvanostatic cycling studies, electrochemical impedance spectroscopy (EIS) and differential capacity curves (dQ/dE). XRD patterns of LiMn<sub>2</sub>O<sub>4</sub> and LiCu<sub>x</sub>Cr<sub>y</sub>Mn<sub>2-x-y</sub>O<sub>4</sub> confirm high degree of crystallinity with good phase purity. FESEM image of undoped pristine spinel lucidly depicts cauliflower morphology with good agglomerated particle size of 50 nm while 0.5-Cu doped samples depict the pebbles morphology. TEM images of the spinel LiMn<sub>2</sub>O<sub>4</sub> and LiCu<sub>0.5</sub>Cr<sub>0.05</sub>Mn<sub>1.45</sub>O<sub>4</sub> authenticate that all the synthesized particles via sol-gel method are nano-sized (100 nm) with spherical surface and cloudy particles morphology. The LiMn<sub>2</sub>O<sub>4</sub> samples calcined at 850℃ deliver the high discharge capacity of 130 mA·h/g with cathodic efficiency of 88% corresponds to 94% columbic efficiency in the first cycle. Among all four compositions studied, LiCu<sub>0.5</sub>Cr<sub>0.05</sub>Mn<sub>1.45</sub>O<sub>4</sub> delivers 124 mA·h/g during the first cycle and shows stable performance with a low capacity fade of 1.1 mA·h/g cycle over the investigated 10 cycles.
基金the National Natural Science Foundation of China(No.50272012).
文摘LiMn2O4 powder as a cathode materials for rechargeable lithium-ion batteries was prepared by solid-state reaction from LitCO3 and electrolytic MnOz at different sintering periods （2, 6, 18, and 32 h）. X-ray diffraction （XRD） patterns of the prepared samples are identified as the spinel structure with a space group of Fd3 m. The lattice parameters almost remain the same as the sintering periods increase. The sample with a sintering period of 32 h shows good cycling performance at both low and nigh current densities, and also elevated temperature. It is believed that the excellent electrochemical behavior of this sample results from its good crystallinity and large grain size compared with other samples. Different electrochemical measurements were conducted to investigate the electrochemical properties of spinel LiMn204. 2008 University of Science and Technology Beijing. All rights reserved.
文摘Multi-doped spinels, namely LiMn204 and LiZnxHoyMn2 x yO4 （x=0.10-0.18; y= 0.02-0.10）, for use as cathode materials for lithium-ion rechargeable batteries were synthesized via sol-gel method, using lauric acid as the chelating agent, to obtain micron-sized particles. The physical properties of the synthesized samples were investigated using differential thermal analysis, Fourier-transform infrared spectroscopy, X-ray diffraction （XRD）, scanning electron microscopy （SEM）, transmission electron microscopy, energy-dispersive X-ray analysis, and electrochemical methods. XRD showed that LiMn204 and LiZnxHoyMn2_x y04 have high degrees of crystallinity and good phase purities. The SEM images of LiMn204 showed an ice-cube morphology with particles of size 1 μm. Charge-discharge studies showed that undoped LiMn2 O4 delivered the discharge capacity of 124 mA h/g with coulombic efficiency of 95% during the first cycle, whereas doped spinels delivered discharge capacities of 125, 120, and 127 mA h/g in the first cycle with coulombic efficiencies of 96%, 91%, and 91%, respectively.
文摘Hierarchical yolk-shell structured cathodes with controllable composition are potentially attractive materials for the fabrication of lithium-ion batteries, but they are difficult to synthesize. In this work, we present a simple, scalable, and general morphology-inheritance strategy to synthesize spinel manganese cathodes with a hierarchical yolk-shell structure. Starting from uniform Mn carbonate spheres prepared by an ultrafast and scalable microwave-assisted method, we show that the subsequent sintering results in the formation of Mn203 precursors with a yolk-shell structure, which can be effectively transferred to spinel manganese cathodes via simple impregnation and solid-state reaction. Owing to the simple and scalable nature of the present strategy, materials prepared through this approach have great potential as cathodes of lithium-ion batteries, where they can lead to high specific capacity, outstanding cyclability, and superior rate capability. In particular, both LiMn204 and LiNi05Mn1504 with hierarchical yolk-shell structure achieved nearly theoretical capacity, without any apparent decay after 100 cycles at I C. Moreover, 80% of the initial discharge capacities of both samples can be maintained for up to 500 cycles at a high rate of 10 C.
基金the financial support from the Open Fund of Energy and Materials Chemistry Joint Laboratory of SCNU and TINCI,China(SCNU-TINCI-202207)supported by the Natural Science Foundation of China(No.52302283).
文摘Spinel LiMn_(2)O_(4)(LMO)is deemed to be a promising cathode material for commercial lithium-ion batteries(LIBs)in prospect of its cost-effectiveness,nontoxicity,fabulous rate capability,and high energy density.Nevertheless,the LMO is inevitably confronted with sluggish diffusion kinetics and drastic capacity degradation triggered by multiple issues,including Jahn-Teller distortion,Mn dissolution,and structural attenuation.Thereinto,a metal-organic framework(MOF)chemistry engineering for hierarchical micro-/nano-structural F,O-dual-doped carbon embedded oxygen vacancy enriched LiMn_(2)O_(4)cathode(OV-LMO@FOC)is proposed for longevous LIBs.Bestowed by experimental and theoretical implementations,systematic investigations of OV-LMO@FOC endow that the meticulous integration of F,O-dual-doped carbon and oxygen vacancy in LMO-based cathode reconfigures the electronic structure,boosts electronic conductivity,expedites diffusion capability,facilitates energetically preferable Li^(+) adsorption,and suppresses Mn dissolution in the electrolyte,consequently achieving fabulous long-term cycling stability.As expected,the OV-LMO@FOC behaves with compelling electrochemical performance with prosperous reversible capacity(130.2 mAh g^(−1)at 0.2 C upon 200 cycles),exceptional rate capacity(93.7 mAh g^(−1) even at 20 C),and pronounced long-term cyclability(112.5 mAh g^(−1)after 1200 cycles with 77.6%capacity retention at 1 C).Even at the ultrahigh current density of 5 C,the OV-LMO@FOC bears a brilliant capacity of 96.9 mAh g^(−1)upon 1000 cycles with an extraordinary capacity retention of 90.7%,and maintains a discharge capacity of 70.9 mAh g^(−1)upon 4000 cycles.This work envisions the MOF-chemistry in surface modification and electronic modulation engineering of high-performance cathode materials towards industrialization in automotive market.
