Ni-rich cathodes exhibit appealing properties,such as high capacity density,low cost,and prominent energy density.However,the inferior ionic conductivity and bulk structural degradation become bottlenecks for Ni-rich ...Ni-rich cathodes exhibit appealing properties,such as high capacity density,low cost,and prominent energy density.However,the inferior ionic conductivity and bulk structural degradation become bottlenecks for Ni-rich cathodes and severely limit their commercial utilization.Traditional coating and doping methods suffer fatal drawbacks in functioning as a unit and cannot radically promote material performance to meet the needs of Li-ion batteries(LIBs).Herein,we successfully devised an ingenious and facile synthetic method to establish Ni-rich oxides with a La_(2)Zr_(2)O_(7) coating and Zr doping.The coating layer improves the ion diffusion kinetics and enhances Li-ion transportation while Zr doping effectively suppresses the phase transition of LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2) cathode.Owing to the synergetic effect of Zr doping and La_(2)Zr_(2)O_(7) coating,the modified material shows prominent initial discharge capacity of 184.7 m Ah g^(-1) at 5℃ and maintains 177.5 m Ah g^(-1) after 100 cycles at 1℃.Overall,the proposed feasible electrode design method can have a far-reaching impact on further fabrication of advanced cathodes for high-performance LIBs.展开更多
Spinel-type lithium and titanium composite oxide Li4TisO12 was successfully synthesized via a novel hydrolysis method followed by calcination using titanium tetrachloride （TIC14） and lithium hydroxide （LiOH.H2O） a...Spinel-type lithium and titanium composite oxide Li4TisO12 was successfully synthesized via a novel hydrolysis method followed by calcination using titanium tetrachloride （TIC14） and lithium hydroxide （LiOH.H2O） as raw materials. Three major factors, including LiOH con- centration, LiOH dosage, and hydrolysis temperature were studied for optimizing the synthetic conditions to obtain a phase-pure Li4Ti5012. The physical and electrochemical properties of samples were characterized by X-ray dif- fraction （XRD）, thermogravimetric analysis （TGA）, fourier transform infrared spectroscopy （FT-IR）, scanning electron microscopy （SEM）, and constant current discharge-charge test. The FT-IR results indicate the presence of [TiO6] octahedra. The SEM images show that the Li4Ti5O12 pre- cursor obtained is an amorphous solid with an irregular and rough morphology. It is revealed that the phase-pure spinel Li4Ti5O12 powders with well crystallization and regular morphology can be obtained by calcining the precursor at 800 ℃ for 6 h. The constant current discharge-charge tests indicate that the Li4TisO12 material delivers an excellent cycling ability, maintaining 93.8 % of its initial specific capacity after 60 cycles at a current density of 0.5C.展开更多
Lithium-ion batteries(LIBs)represent the most promising choice for meeting the ever-growing demand of society for various electric applications,such as electric transportation,portable electronics,and grid storage.Nic...Lithium-ion batteries(LIBs)represent the most promising choice for meeting the ever-growing demand of society for various electric applications,such as electric transportation,portable electronics,and grid storage.Nickel-rich layered oxides have largely replaced LiCoO_(2)in commercial batteries because of their low cost,high energy density,and good reliability.Traditional nickel-based oxide particles,usually called polycrystal materials,are composed of microsized primary particles.However,polycrystal particles tend to suffer from pulverization and severe side reactions along grain boundaries during cycling.These phenomena accelerate cell degradation.Single-crystal materials,which exhibit robust mechanical strength and a high surface area,have great potential to address the challenges that hinder their polycrystal counterparts.A comprehensive understanding of the growing body of research related to single-crystal materials is imperative to improve the performance of cathodes in LIBs.This review highlights origins,recent developments,challenges,and opportunities for single-crystal layered oxide cathodes.The synthesis science behind single-crystal materials and comparative studies between single-crystal and polycrystal materials are discussed in detail.Industrial techniques and facilities are also reviewed in combination with our group’s experiences in single-crystal research.Future development should focus on facile production with strong control of the particle size and distribution,structural defects,and impurities to fully reap the benefits of single-crystal materials.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.51974368)the Fundamental Research Funds for the Central Universities of Central South University(2019zzts251)。
文摘Ni-rich cathodes exhibit appealing properties,such as high capacity density,low cost,and prominent energy density.However,the inferior ionic conductivity and bulk structural degradation become bottlenecks for Ni-rich cathodes and severely limit their commercial utilization.Traditional coating and doping methods suffer fatal drawbacks in functioning as a unit and cannot radically promote material performance to meet the needs of Li-ion batteries(LIBs).Herein,we successfully devised an ingenious and facile synthetic method to establish Ni-rich oxides with a La_(2)Zr_(2)O_(7) coating and Zr doping.The coating layer improves the ion diffusion kinetics and enhances Li-ion transportation while Zr doping effectively suppresses the phase transition of LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2) cathode.Owing to the synergetic effect of Zr doping and La_(2)Zr_(2)O_(7) coating,the modified material shows prominent initial discharge capacity of 184.7 m Ah g^(-1) at 5℃ and maintains 177.5 m Ah g^(-1) after 100 cycles at 1℃.Overall,the proposed feasible electrode design method can have a far-reaching impact on further fabrication of advanced cathodes for high-performance LIBs.
基金financial supports from the National Natural Science Foundation of China (51974368)the Fundamental Research Funds of the Central South University,China。
基金financially supported by the National Natural Science Foundation of China(No.50774103)
文摘Spinel-type lithium and titanium composite oxide Li4TisO12 was successfully synthesized via a novel hydrolysis method followed by calcination using titanium tetrachloride （TIC14） and lithium hydroxide （LiOH.H2O） as raw materials. Three major factors, including LiOH con- centration, LiOH dosage, and hydrolysis temperature were studied for optimizing the synthetic conditions to obtain a phase-pure Li4Ti5012. The physical and electrochemical properties of samples were characterized by X-ray dif- fraction （XRD）, thermogravimetric analysis （TGA）, fourier transform infrared spectroscopy （FT-IR）, scanning electron microscopy （SEM）, and constant current discharge-charge test. The FT-IR results indicate the presence of [TiO6] octahedra. The SEM images show that the Li4Ti5O12 pre- cursor obtained is an amorphous solid with an irregular and rough morphology. It is revealed that the phase-pure spinel Li4Ti5O12 powders with well crystallization and regular morphology can be obtained by calcining the precursor at 800 ℃ for 6 h. The constant current discharge-charge tests indicate that the Li4TisO12 material delivers an excellent cycling ability, maintaining 93.8 % of its initial specific capacity after 60 cycles at a current density of 0.5C.
基金the National Natural Science Foundation of China(Grant Nos.51974368 and 51774333).
文摘Lithium-ion batteries(LIBs)represent the most promising choice for meeting the ever-growing demand of society for various electric applications,such as electric transportation,portable electronics,and grid storage.Nickel-rich layered oxides have largely replaced LiCoO_(2)in commercial batteries because of their low cost,high energy density,and good reliability.Traditional nickel-based oxide particles,usually called polycrystal materials,are composed of microsized primary particles.However,polycrystal particles tend to suffer from pulverization and severe side reactions along grain boundaries during cycling.These phenomena accelerate cell degradation.Single-crystal materials,which exhibit robust mechanical strength and a high surface area,have great potential to address the challenges that hinder their polycrystal counterparts.A comprehensive understanding of the growing body of research related to single-crystal materials is imperative to improve the performance of cathodes in LIBs.This review highlights origins,recent developments,challenges,and opportunities for single-crystal layered oxide cathodes.The synthesis science behind single-crystal materials and comparative studies between single-crystal and polycrystal materials are discussed in detail.Industrial techniques and facilities are also reviewed in combination with our group’s experiences in single-crystal research.Future development should focus on facile production with strong control of the particle size and distribution,structural defects,and impurities to fully reap the benefits of single-crystal materials.
