Nanostructured MnO2/CNT composite was synthesized by a soft template approach in the presence of Pluronic P123 surfactant. The product was characterized by X-ray diffraction, thermogravimetric and differential thermal...Nanostructured MnO2/CNT composite was synthesized by a soft template approach in the presence of Pluronic P123 surfactant. The product was characterized by X-ray diffraction, thermogravimetric and differential thermal analyses, Fourier transformed infrared spectroscopy and high-resolution transmission electron microscopy. The results show that the sample consists of poor crystalline α-MnO2 nanorods with a diameter of about 10 nm and a length of 30-50 nm, which absorb on the carbon nanotubes. The electrochemical properties of the product as cathode material for Li-MnO2 cell are evaluated by galvanostatic charge-discharge and electrochemical impedance spectroscopy （EIS）. Compared with pure MnO2 electrode, the MnO2/CNT composite delivers a much larger initial capacity of 275.3 mA-h/g and better rate and cycling performance.展开更多
The commercialized lithium secondary cells need the electrode materials with high speeific capacity, lower pollution and lower price. Certain industrial materials ( NiSO_4, CoSO_4 , LiOH·H_2O)were used to synthes...The commercialized lithium secondary cells need the electrode materials with high speeific capacity, lower pollution and lower price. Certain industrial materials ( NiSO_4, CoSO_4 , LiOH·H_2O)were used to synthesize Ni_(0.8)Co_(0.2)(OH)_2 of a stratified structure, when various synthesis conditions such as pH, reaction temperature et al. were controlled strictly. After LiOH·H_2O and Ni_(0.8)Co_(0.2) (OH)_2were calcinated in air atmosphere, LiNi_(0.8)Co_(0.2)O_2 positive electrode materials with good layered crystal structure was obtained. Tests showed that the optimal calcination temperature in air atmosphere was about at 720℃ and LiNi_(0.8)Co_(0.2)O_2 synthesized in the above conditions had good electrochemical properties and a low cost. The first specific: discharge capacity of the material was 186 mAh/g, and the specific discharge capacity was 175 mAh/g after 50 cycles at a 0.2C rate, between 3.0～4.2 V with a discharge deterioration ratio of 0.22% each cycle. Tests showed that LiNi_(0.8)Co_(0.2)O_2 positive electrode materials was a promising candidate to replace the commereialized LiCoO_2 for lithium secondary batteries.展开更多
The physics that associated with the performance of lithium secondary batteries(LSB)are reviewed.The key physical problems in LSB include the electronic conduction mechanism,kinetics and thermodynamics of lithium ion ...The physics that associated with the performance of lithium secondary batteries(LSB)are reviewed.The key physical problems in LSB include the electronic conduction mechanism,kinetics and thermodynamics of lithium ion migration,electrode/electrolyte surface/interface,structural(phase)and thermodynamics stability of the electrode materials,physics of intercalation and deintercalation.The relationship between the physical/chemical nature of the LSB materials and the batteries performance is summarized and discussed.A general thread of computational materials design for LSB materials is emphasized concerning all the discussed physics problems.In order to fasten the progress of the new materials discovery and design for the next generation LSB,the Materials Genome Initiative(MGI)for LSB materials is a promising strategy and the related requirements are highlighted.展开更多
High-tap density electrode materials are greatly desired for Li-ion batteries with high volumetric capacities to fulfill the growing demands of electric vehicles and portable smart devices. TiOz, which is one of the m...High-tap density electrode materials are greatly desired for Li-ion batteries with high volumetric capacities to fulfill the growing demands of electric vehicles and portable smart devices. TiOz, which is one of the most attractive an- ode materials, is limited in their application for Li-ion batteries because of its low tap density （usually 〈1 gcm-3） and volumetric capacity. Herein, we report uniform mesoporous TiO2 submicrospheres with a tap density as high as 1.62 gcm-3 as a promising anode material. Even with a high mass load- ing of 24 mg cm-2, the TiO2 submicrospheres have impressive volumetric capacities that are more than double those of their counterparts. Moreover, they can be synthesized with -100% yield and within a reaction time of -6 h by optimizing the experimental conditions and formation mechanism, exhibiting potential for large-scale production for industrial applications. Other mesoporous anode materials, i.e., hightap density mesoporous Li4Ti5O12 submicrospheres, are fabricated using the generalized method. We believe that our work provides a significant reference for the industrial production of mesoporous materials for Li-ion batteries with a high volumetric performance.展开更多
基金Projects(21071153,20976198)supported by the National Natural Science Foundation of China
文摘Nanostructured MnO2/CNT composite was synthesized by a soft template approach in the presence of Pluronic P123 surfactant. The product was characterized by X-ray diffraction, thermogravimetric and differential thermal analyses, Fourier transformed infrared spectroscopy and high-resolution transmission electron microscopy. The results show that the sample consists of poor crystalline α-MnO2 nanorods with a diameter of about 10 nm and a length of 30-50 nm, which absorb on the carbon nanotubes. The electrochemical properties of the product as cathode material for Li-MnO2 cell are evaluated by galvanostatic charge-discharge and electrochemical impedance spectroscopy （EIS）. Compared with pure MnO2 electrode, the MnO2/CNT composite delivers a much larger initial capacity of 275.3 mA-h/g and better rate and cycling performance.
文摘The commercialized lithium secondary cells need the electrode materials with high speeific capacity, lower pollution and lower price. Certain industrial materials ( NiSO_4, CoSO_4 , LiOH·H_2O)were used to synthesize Ni_(0.8)Co_(0.2)(OH)_2 of a stratified structure, when various synthesis conditions such as pH, reaction temperature et al. were controlled strictly. After LiOH·H_2O and Ni_(0.8)Co_(0.2) (OH)_2were calcinated in air atmosphere, LiNi_(0.8)Co_(0.2)O_2 positive electrode materials with good layered crystal structure was obtained. Tests showed that the optimal calcination temperature in air atmosphere was about at 720℃ and LiNi_(0.8)Co_(0.2)O_2 synthesized in the above conditions had good electrochemical properties and a low cost. The first specific: discharge capacity of the material was 186 mAh/g, and the specific discharge capacity was 175 mAh/g after 50 cycles at a 0.2C rate, between 3.0～4.2 V with a discharge deterioration ratio of 0.22% each cycle. Tests showed that LiNi_(0.8)Co_(0.2)O_2 positive electrode materials was a promising candidate to replace the commereialized LiCoO_2 for lithium secondary batteries.
基金supported by the National Natural Science Foundation of China(Grant Nos.11234013,11064004 and 11264014)supported by the"Gan-po talent 555"project of Jiangxi Province
文摘The physics that associated with the performance of lithium secondary batteries(LSB)are reviewed.The key physical problems in LSB include the electronic conduction mechanism,kinetics and thermodynamics of lithium ion migration,electrode/electrolyte surface/interface,structural(phase)and thermodynamics stability of the electrode materials,physics of intercalation and deintercalation.The relationship between the physical/chemical nature of the LSB materials and the batteries performance is summarized and discussed.A general thread of computational materials design for LSB materials is emphasized concerning all the discussed physics problems.In order to fasten the progress of the new materials discovery and design for the next generation LSB,the Materials Genome Initiative(MGI)for LSB materials is a promising strategy and the related requirements are highlighted.
基金supported by the National High Technology Research and Development Program of China (2013AA050901)the National Basic Research Program of China (2015CB251100)+2 种基金the Thousand Youth Talents Programthe National Natural Science Foundation of China(51602173,51371015 and 11674023)China Postdoctoral Science Foundation(2016M591186)
文摘High-tap density electrode materials are greatly desired for Li-ion batteries with high volumetric capacities to fulfill the growing demands of electric vehicles and portable smart devices. TiOz, which is one of the most attractive an- ode materials, is limited in their application for Li-ion batteries because of its low tap density （usually 〈1 gcm-3） and volumetric capacity. Herein, we report uniform mesoporous TiO2 submicrospheres with a tap density as high as 1.62 gcm-3 as a promising anode material. Even with a high mass load- ing of 24 mg cm-2, the TiO2 submicrospheres have impressive volumetric capacities that are more than double those of their counterparts. Moreover, they can be synthesized with -100% yield and within a reaction time of -6 h by optimizing the experimental conditions and formation mechanism, exhibiting potential for large-scale production for industrial applications. Other mesoporous anode materials, i.e., hightap density mesoporous Li4Ti5O12 submicrospheres, are fabricated using the generalized method. We believe that our work provides a significant reference for the industrial production of mesoporous materials for Li-ion batteries with a high volumetric performance.
