锂离子电池纳米电极薄膜的喷墨打印研究

用喷墨打印的方法制作了锂离子电池纳米结构正负极材料的电极薄膜.以纳米颗粒状Li4Ti5O12负极和LiFePO4正极材料为例,研究了Tween-80和FC-4430两种表面活性剂对电极材料墨水的影响.研究表明,电极材料墨水是喷墨打印制备锂离子电池膜片的关键,添加剂成分对电池材料墨水性能的电化学稳定性、分散性和可喷性有较大影响.与Tween-80相比,利用FC-4430制备的Li4Ti5O12墨水和LiFePO4墨水打印的电极膜片表现出较好的循环性能和库伦效率.其原因是由于全氟类表面活性剂(如FC-4430)具有较好的电化学稳定性.

Facile synthesis of hierarchically structured manganese oxides as anode for lithium-ion batteries

Developing high-performance lithium ion batteries(LIBs)using manganese oxides as anodes is attractive due to their high theoretical capacity and abundant resources.Herein,we report a facile synthesis of hierarchical spherical MnO2 containing coherent amorphous/crystalline domained by a simple yet effective redox precipitation reaction at room temperature.Further,flower-like CoMn2O4 constructed by single-crystalline spinel nanosheets has been fabricated using MnO2 as precursor.This mild methodology avoids undesired particle aggregation and loss of active surface area in conventional hydrothermal or solid-state processes.Moreover,both MnO2 and CoMn2O4 nanosheets manifest superior lithium-ion storage properties,rendering them promising applications in LIBs and other energy-related fields.

Hierarchically nanostructured transition metal oxides for supercapacitors

Highly efficient, clean, and sustainable electrochemical energy storage technologies have been investigated extensively to counter the shortage of fossil fuels and increasingly prominent environmental problems. Supercapacitors（SCs） have received wide attention as critical devices for electrochemical energy storage because of their rapid charging-discharging capability and long life cycle. Various transition metal oxides（TMOs）, such as MnO_2, NiO, Co_3O_4,and CuO, have been extensively studied as electrode materials for SCs. Compared with carbon and conducting polymers,TMO materials can achieve higher specific capacitance. For further improvement of electrochemical performance, hierarchically nano structured TMO materials have become a hot research area for electrode materials in SCs. The hierarchical nanostructure can not only offer abundant accessible electroactive sites for redox reactions but also shorten the ion diffusion pathway. In this review, we provide an overall summary and evaluation of the recent progress of hierarchically nano structured TMOs for SCs, including synthesis methods, compositions, structures, and electrochemical performances. Both single-phase TMOs and the composites based on TMOs are summarized. Furthermore, we also prospect the developing foreground of this field. In this view, the important directions mainly include： the nanocomposites of TMOs materials with conductive materials; the cobalt-based materials and the nickel-based materials; the improvement of the volume energy density, the asymmetric SCs, and the flexible all-solid-state SCs.

Evaluating the performance of nanostructured materials as lithium-ion battery electrodes

The performance of the lithium-ion cell is heavily dependent on the ability of the host electrodes to accommodate and release Li＋ ions from the local structure. While the choice of electrode materials may define parameters such as cell potential and capacity, the process of intercalation may be physically limited by the rate of solid-state Li＋ diffusion. Increased diffusion rates in lithium-ion electrodes may be achieved through a reduction in the diffusion path, accomplished by a scaling of the respective electrode dimensions. In addition, some electrodes may undergo large volume changes associated with charging and discharging, the strain of which, may be better accommodated through nanostructuring. Failure of the host to accommodate such volume changes may lead to pulverisation of the local structure and a rapid loss of capacity. In this review article, we seek to highlight a number of significant gains in the development of nanostructured lithium-ion battery architectures （both anode and cathode）, as drivers of potential next-generation electrochemical energy storage devices.

Hierarchical SnO_2 nanoflowers assembled by atomic thickness nanosheets as anode material for lithium ion battery

Hierarchical SnO2 nanoflowers assembled by atomic thickness nanosheets were prepared by facile one-pot solvothermal method with acetone/water mixture as solvent. The crystal structure, morphology and the microstructure of the as-prepared products were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and atomic force microscope （AFM）. Results revealed that the nanoflowers （2-4 μm） were assembled by the ultrathin SnO2 nanosheets （3.1 nm esti- mated by AFM）. When tested as anode material for lithium ion batteries, the SnO2 nanoflowers showed improved cy- cling stability comparing with the commercial SnO2 parti- cles. The reversible charge capacity of SnO2 nanoflowers maintained 350.7 mAh/g after 30 cycles, while that of the commercial SnO2 was only 112.2 mAh/g. The high re- versible capacity and good cycling stability could be ascri- bed to the hierarchical nanostructure, atomic thickness nanosheets and large surface area of the SnO2 nanoflowers.