Progressive delamination driven by Li-ion diffusion in elastic disk-like thin film electrodes of Li-ion batteries is modeled based on the cohesive model. Axisymmetric diffusion model is considered under both galvanost...Progressive delamination driven by Li-ion diffusion in elastic disk-like thin film electrodes of Li-ion batteries is modeled based on the cohesive model. Axisymmetric diffusion model is considered under both galvanostatic and potentiostatic operations. The effect of edge diffusion on the delamination process is evaluated. It is found that the diffusion from edge leads to an earlier delamination initiation. The edge effect is significant for active disks with a small aspect ratio, but negligible for the case of large aspect ratio. The edge diffusion is weaker in the potentiostatic operation than in the galvanostatic operation.展开更多
By employing the two-dimensional analysis, i.e.,plane strain and plane stress, a semi-analytical method is developed to investigate the interfacial delamination in electrodes. The key parameters are obtained from the ...By employing the two-dimensional analysis, i.e.,plane strain and plane stress, a semi-analytical method is developed to investigate the interfacial delamination in electrodes. The key parameters are obtained from the governing equations, and their effects on the evolution of the delamination are evaluated. The impact of constraint perpendicular to the plane is also investigated by comparing the plane strain and plane stress. It is found that the delamination in the plane strain condition occurs easier, indicating that the constraint is harmful to maintain the structure stability. According to the obtained governing equations, a formula of the dimensionless critical size for delamination is provided, which is a function of the maximum volumetric strain and the Poisson’s ratio of the active layer.展开更多
Thin-film lithium-ion batteries are the most competitive power sources for various kinds of micro-electro-mechanical systems and have been extensively researched.The present paper reviews the recent progress on Sn-bas...Thin-film lithium-ion batteries are the most competitive power sources for various kinds of micro-electro-mechanical systems and have been extensively researched.The present paper reviews the recent progress on Sn-based thin-film anode materials,with particular emphasis on the preparation and performances of pure Sn,Sn-based alloy,and Sn-based oxide thin films.From this survey,several conclusions can be drawn concerning the properties of Sn-based thin-film anodes.Pure Sn thin films deliver high reversible capacity but very poor cyclability due to the huge volume changes that accompany lithium insertion/extraction.The cycle performance of Sn-based intermetallic thin films can be enhanced at the expense of their capacities by alloying with inactive transition metals.In contrast to anodes in which Sn is alloyed with inactive transition metals,Sn-based nanocomposite films deliver high capacity with enhanced cycle performance through the incorporation of active elements.In comparison with pure Sn anodes,Sn-based oxide thin films show greatly enhanced cyclability due to the in situ formation of Sn nanodispersoids in an Li2O matrix,although there is quite a large initial irreversible capacity loss.For all of these anodes,substantial improvements have been achieved by micro-nanostructure tuning of the active materials.Based on the progress that has already been made on the relationship between the properties and microstructures of Sn-based thin-film anodes,it is believed that manipulating the multi-phase and multi-scale structures offers an important means of further improving the capacity and cyclability of Sn-based alloy thin-film anodes.展开更多
采用水热法结合银镜反应制备出一系列不同Ag负载量(2.2%、4.0%、6.4%,w/w)改性的3D纳米网状结构Ag@Ti O2薄膜电极。利用电感耦合等离子体技术(ICP)、X射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)和X射线能谱(EDX)等表征手段测试所合...采用水热法结合银镜反应制备出一系列不同Ag负载量(2.2%、4.0%、6.4%,w/w)改性的3D纳米网状结构Ag@Ti O2薄膜电极。利用电感耦合等离子体技术(ICP)、X射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)和X射线能谱(EDX)等表征手段测试所合成材料的形貌及成分,实验结果表明Ag纳米颗粒可以成功沉积在Ti O2纳米线表面。电化学测试数据则表明,4.0%(w/w)负载量的Ag@Ti O2相比于未改性和其他负载量的Ti O2纳米线具有更好的倍率性能和更稳定的可逆容量。在50,100,200,400,800和1 200 m A·g^(-1)的电流密度条件下,该改性电极的放电容量可分别达到261.4,253.7,239.5,216.5,193.1和185.1 m Ah·g^(-1),在200 m A·g^(-1)下循环80次后容量保持率仍能达到99.8%。展开更多
基金supported by the National Science Foundation of China (11102103 and 11172159)the Shanghai Municipal Education Commission, China (13ZZ070)+1 种基金the Graduate School of Shanghai University (SHUCX120123)the Science and Technology Commission of Shanghai Municipality, China(12ZR1410200)
文摘Progressive delamination driven by Li-ion diffusion in elastic disk-like thin film electrodes of Li-ion batteries is modeled based on the cohesive model. Axisymmetric diffusion model is considered under both galvanostatic and potentiostatic operations. The effect of edge diffusion on the delamination process is evaluated. It is found that the diffusion from edge leads to an earlier delamination initiation. The edge effect is significant for active disks with a small aspect ratio, but negligible for the case of large aspect ratio. The edge diffusion is weaker in the potentiostatic operation than in the galvanostatic operation.
文摘By employing the two-dimensional analysis, i.e.,plane strain and plane stress, a semi-analytical method is developed to investigate the interfacial delamination in electrodes. The key parameters are obtained from the governing equations, and their effects on the evolution of the delamination are evaluated. The impact of constraint perpendicular to the plane is also investigated by comparing the plane strain and plane stress. It is found that the delamination in the plane strain condition occurs easier, indicating that the constraint is harmful to maintain the structure stability. According to the obtained governing equations, a formula of the dimensionless critical size for delamination is provided, which is a function of the maximum volumetric strain and the Poisson’s ratio of the active layer.
基金supported by the National Natural Science Foundation of China (50971060)the Fundamental Research Funds for the Central Universities (2012ZM0001)
文摘Thin-film lithium-ion batteries are the most competitive power sources for various kinds of micro-electro-mechanical systems and have been extensively researched.The present paper reviews the recent progress on Sn-based thin-film anode materials,with particular emphasis on the preparation and performances of pure Sn,Sn-based alloy,and Sn-based oxide thin films.From this survey,several conclusions can be drawn concerning the properties of Sn-based thin-film anodes.Pure Sn thin films deliver high reversible capacity but very poor cyclability due to the huge volume changes that accompany lithium insertion/extraction.The cycle performance of Sn-based intermetallic thin films can be enhanced at the expense of their capacities by alloying with inactive transition metals.In contrast to anodes in which Sn is alloyed with inactive transition metals,Sn-based nanocomposite films deliver high capacity with enhanced cycle performance through the incorporation of active elements.In comparison with pure Sn anodes,Sn-based oxide thin films show greatly enhanced cyclability due to the in situ formation of Sn nanodispersoids in an Li2O matrix,although there is quite a large initial irreversible capacity loss.For all of these anodes,substantial improvements have been achieved by micro-nanostructure tuning of the active materials.Based on the progress that has already been made on the relationship between the properties and microstructures of Sn-based thin-film anodes,it is believed that manipulating the multi-phase and multi-scale structures offers an important means of further improving the capacity and cyclability of Sn-based alloy thin-film anodes.
基金supported by the National Key Basic Research Program of China(2007CB209705)National Natural Science Foundation of China(21006063,21073120)Science and Technology Commission of Shanghai Municipality,China(10DZ1202702)~~
文摘采用水热法结合银镜反应制备出一系列不同Ag负载量(2.2%、4.0%、6.4%,w/w)改性的3D纳米网状结构Ag@Ti O2薄膜电极。利用电感耦合等离子体技术(ICP)、X射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)和X射线能谱(EDX)等表征手段测试所合成材料的形貌及成分,实验结果表明Ag纳米颗粒可以成功沉积在Ti O2纳米线表面。电化学测试数据则表明,4.0%(w/w)负载量的Ag@Ti O2相比于未改性和其他负载量的Ti O2纳米线具有更好的倍率性能和更稳定的可逆容量。在50,100,200,400,800和1 200 m A·g^(-1)的电流密度条件下,该改性电极的放电容量可分别达到261.4,253.7,239.5,216.5,193.1和185.1 m Ah·g^(-1),在200 m A·g^(-1)下循环80次后容量保持率仍能达到99.8%。
