Nickel-rich cathode materials have received widespread attention due to their high energy density.However,the poor rate capability and inferior cycle stability seriously hinder their large-scale application.The tradit...Nickel-rich cathode materials have received widespread attention due to their high energy density.However,the poor rate capability and inferior cycle stability seriously hinder their large-scale application.The traditional co-precipitation method for preparing them has a long process and easily arises agglomeration leading to inhomogeneous element distribution.Here,a novel precursor containing Li element was prepared by ultrafast spray pyrolysis(SP)in 3–5 s.Then the precursor was used to synthesize pristine LiNi_(0.9)Co_(0.05)Mn_(0.05)O_(2)(NCM90)and 1%Mg modified LiNi_(0.9)Co_(0.05)Mn_(0.05)O_(2)(NCM90-Mg1).This method gets rid of mixing Li/Mg source and the precursor prepared by common co-precipitation,thus could achieve homogeneous lithiation and Mg2+doping.The cell parameter c is expanded,and the cation disorder is reduced after Mg2+doping.Furthermore,the harmful H2-H3 phase transition in NCM90-Mg1 is also well suppressed.As a result,the obtained NCM90-Mg1 shows better electrochemical performance than NCM90.Within 2.8–4.3 V(25℃),the specific discharge capacity of NCM90-Mg1 at 5 C is as high as 169.1m Ah/g,and an outstanding capacity retention of 70.0%(10.0%higher than NCM90)can be obtained after400 cycles at 0.5 C.At 45℃,a capacity retention of 81.9%after 100 cycles at 1 C is recorded for NCM90-Mg1.Moreover,the NCM90-Mg1 also exhibits superior cycle stability when cycled at high cut-off voltage(4.5 V,25℃),possessing the capacity retention of 79.2%after 200 cycles at 1 C.Therefore,SP can be proposed as a powerful method for the preparation of multi-element materials for next-generation high energy density LIBs.展开更多
The ultra-high nickel cathode material has important application prospect in power lithium-ion batteries.However,the poor structural stability and serious surface/interfacial side reactions during long cycles severely...The ultra-high nickel cathode material has important application prospect in power lithium-ion batteries.However,the poor structural stability and serious surface/interfacial side reactions during long cycles severely hinder the material's practical application.In this paper,Cs^(+)doping and polymethyl methacrylate(PMMA)coating are used to synergistically modify the NCM955 material.The results show that the corresponding discharge specific capacity of NCMCs-2@P-2 material reaches 152.02 m Ah/g at 1 C(1 C=200 m A/g)and 125.66 m Ah/g at 5 C after 300 cycles,and the capacity retention is 78.11%and72.21%,respectively.In addition,it still maintains 156.36 m Ah/g discharge specific capacity at 10 C,and these rate and cycle properties exceed those reported on ultra-high nickel cathode material.Moreover,NCMCs-2@P-2 material has higher migration energy barrier of Ni^(2+)and lower migration energy barrier of Li+than that of NCM955 material.Therefore,NCMCs-2@P-2 material has excellent electrochemical properties,which has been proved by a series of structural characterization,theoretical calculation and performance test.The synergistic enhancement of Cs^(+)doping and PMMA coating accelerates lithium ion diffusion kinetics,stabilizes crystal structure,and inhabits surface/interface side reaction.展开更多
Thick-film thermistor with negative temperature coefficient（NTC）, low room-temperature resistivity and modest thermistor constant was screen-printed on the alumina substrate by the combination of 30.94III0.04II0.02 ...Thick-film thermistor with negative temperature coefficient（NTC）, low room-temperature resistivity and modest thermistor constant was screen-printed on the alumina substrate by the combination of 30.94III0.04II0.02 B OBi Coa Co with Ba0.5Bi0.5Fe0.9Sn0.1O3. The electrical properties of the thick films were characterized by a digital multimeter, a Keithley 2400 and an impedance analyzer. The results show that with the Ba0.5Bi0.5Fe0.9Sn0.1O3 content increasing from 0.05 to 0.25, the values of room-temperature resistivity, thermistor constant and peak voltage of the thick films increases and are in the ranges of 1.47-26.5 ？·cm, 678-1345 K and 18.9-47.0 V, respectively. The corresponding current at the peak voltage of the thick films decreases and is in the range of 40-240 m A. The impedance spectroscopy measurement demonstrates that the as-prepared thick films show the abnormal electrical heterogeneous microstructure, consisting of high-resistive grains and less resistive grain boundary regions. It can be concluded that the addition of Ba0.5Bi0.5Fe0.9Sn0.1O3 into 30.94III0.04II0.02 Ba Co OBi Co improves the thermistor behavior and but also deteriorates the current characteristics.展开更多
基金supported by the National Natural Science Foundation of China(No.52122407)the Science and Technology Innovation Program of Hunan Province(No.2022RC3048)。
文摘Nickel-rich cathode materials have received widespread attention due to their high energy density.However,the poor rate capability and inferior cycle stability seriously hinder their large-scale application.The traditional co-precipitation method for preparing them has a long process and easily arises agglomeration leading to inhomogeneous element distribution.Here,a novel precursor containing Li element was prepared by ultrafast spray pyrolysis(SP)in 3–5 s.Then the precursor was used to synthesize pristine LiNi_(0.9)Co_(0.05)Mn_(0.05)O_(2)(NCM90)and 1%Mg modified LiNi_(0.9)Co_(0.05)Mn_(0.05)O_(2)(NCM90-Mg1).This method gets rid of mixing Li/Mg source and the precursor prepared by common co-precipitation,thus could achieve homogeneous lithiation and Mg2+doping.The cell parameter c is expanded,and the cation disorder is reduced after Mg2+doping.Furthermore,the harmful H2-H3 phase transition in NCM90-Mg1 is also well suppressed.As a result,the obtained NCM90-Mg1 shows better electrochemical performance than NCM90.Within 2.8–4.3 V(25℃),the specific discharge capacity of NCM90-Mg1 at 5 C is as high as 169.1m Ah/g,and an outstanding capacity retention of 70.0%(10.0%higher than NCM90)can be obtained after400 cycles at 0.5 C.At 45℃,a capacity retention of 81.9%after 100 cycles at 1 C is recorded for NCM90-Mg1.Moreover,the NCM90-Mg1 also exhibits superior cycle stability when cycled at high cut-off voltage(4.5 V,25℃),possessing the capacity retention of 79.2%after 200 cycles at 1 C.Therefore,SP can be proposed as a powerful method for the preparation of multi-element materials for next-generation high energy density LIBs.
基金supported the National Science Foundation of China(Nos.22362011,22169007,51804199)the Science and Technology Major Project of Guangxi(No.AA19046001)+2 种基金the Open Research Fund of Guangxi Key Laboratory of Electrochemical and Magnetochemical Functional Materials(Nos.EMFM20201105,EMFM20181119)Shenzhen Medical Research Fund(No.20231211121324001)Shenzhen Science and Technology Program(No.KQTD20180412181422399)。
文摘The ultra-high nickel cathode material has important application prospect in power lithium-ion batteries.However,the poor structural stability and serious surface/interfacial side reactions during long cycles severely hinder the material's practical application.In this paper,Cs^(+)doping and polymethyl methacrylate(PMMA)coating are used to synergistically modify the NCM955 material.The results show that the corresponding discharge specific capacity of NCMCs-2@P-2 material reaches 152.02 m Ah/g at 1 C(1 C=200 m A/g)and 125.66 m Ah/g at 5 C after 300 cycles,and the capacity retention is 78.11%and72.21%,respectively.In addition,it still maintains 156.36 m Ah/g discharge specific capacity at 10 C,and these rate and cycle properties exceed those reported on ultra-high nickel cathode material.Moreover,NCMCs-2@P-2 material has higher migration energy barrier of Ni^(2+)and lower migration energy barrier of Li+than that of NCM955 material.Therefore,NCMCs-2@P-2 material has excellent electrochemical properties,which has been proved by a series of structural characterization,theoretical calculation and performance test.The synergistic enhancement of Cs^(+)doping and PMMA coating accelerates lithium ion diffusion kinetics,stabilizes crystal structure,and inhabits surface/interface side reaction.
基金Projects(5110205551462005)supported by the National Natural Science Foundation of China
文摘Thick-film thermistor with negative temperature coefficient（NTC）, low room-temperature resistivity and modest thermistor constant was screen-printed on the alumina substrate by the combination of 30.94III0.04II0.02 B OBi Coa Co with Ba0.5Bi0.5Fe0.9Sn0.1O3. The electrical properties of the thick films were characterized by a digital multimeter, a Keithley 2400 and an impedance analyzer. The results show that with the Ba0.5Bi0.5Fe0.9Sn0.1O3 content increasing from 0.05 to 0.25, the values of room-temperature resistivity, thermistor constant and peak voltage of the thick films increases and are in the ranges of 1.47-26.5 ？·cm, 678-1345 K and 18.9-47.0 V, respectively. The corresponding current at the peak voltage of the thick films decreases and is in the range of 40-240 m A. The impedance spectroscopy measurement demonstrates that the as-prepared thick films show the abnormal electrical heterogeneous microstructure, consisting of high-resistive grains and less resistive grain boundary regions. It can be concluded that the addition of Ba0.5Bi0.5Fe0.9Sn0.1O3 into 30.94III0.04II0.02 Ba Co OBi Co improves the thermistor behavior and but also deteriorates the current characteristics.
