Abstract:The LiMn2O4 hollow nanofibers with a porous structure have been synthesized by modified electrospinning techniques and subsequent thermal treatment. The precursors were electrospun directly onto the fluorine-doped tin oxide (FTO) glass. The heating rate and FTO as substrate play key roles on preparing porous hollow nanofiber. As cathode materials for lithium-ion batteries (LIBs), LiMn2O4 hollow nanofibers showed the high specific capacity of 125.9 mAh/g at 0.1 C and a stable cycling performance, 105.2 mAh/g af… Show more
“…The samples calcined at 900 °C exhibits a more uniform particle size distribution and better crystallinity than the sample sintered at 750 °C. In addition, the images clearly visualizes the truncated surfaces at the vertices and edges of the parental octahedral structure, and the orientation of each surface was assigned following the established face orientation of the octahedral face-center cubic (fcc) framework, that is, {111}, as well as those of its truncated derivatives [37, 38, 39, 40]. Fig.…”
This study succeeded to prepare three pure phases of Mn
2
O
3
, Mn
3
O
4
beside one of the best cathode materials, spinel LiMn
2
O
4
. LiMn
2
O
4
with high phase purity and crystallinity was synthesized by a facile, cost effective and one step synthesis method. The structure and morphology of the powders were studied in detail by means of X-ray diffraction (XRD), thermogravimetric analysis (TGA), field emission scanning electron microscopy (FESEM), transmission electron microscope (TEM) and surface area. The X-ray diffraction shows that the post-annealing process reveals the formation of pure crystalline spinel LiMn
2
O
4
with small particle size and lower lattice strain. The thermogravimetric analysis threw the light on the role of the evaporation technique in producing LiMn
2
O
4
by following the different phases on the thermal performance of the precursor. The morphological characterization shows the clear appearance of the octahedral particles of LiMn
2
O
4
calcined at high temperature with microporous nanosized structure. Electrochemical testing of the as prepared spinel at 900 °C showed promising results in terms of high initial capacity and good cycle stability. The as prepared spinel sample shows also good rate performance.
“…The samples calcined at 900 °C exhibits a more uniform particle size distribution and better crystallinity than the sample sintered at 750 °C. In addition, the images clearly visualizes the truncated surfaces at the vertices and edges of the parental octahedral structure, and the orientation of each surface was assigned following the established face orientation of the octahedral face-center cubic (fcc) framework, that is, {111}, as well as those of its truncated derivatives [37, 38, 39, 40]. Fig.…”
This study succeeded to prepare three pure phases of Mn
2
O
3
, Mn
3
O
4
beside one of the best cathode materials, spinel LiMn
2
O
4
. LiMn
2
O
4
with high phase purity and crystallinity was synthesized by a facile, cost effective and one step synthesis method. The structure and morphology of the powders were studied in detail by means of X-ray diffraction (XRD), thermogravimetric analysis (TGA), field emission scanning electron microscopy (FESEM), transmission electron microscope (TEM) and surface area. The X-ray diffraction shows that the post-annealing process reveals the formation of pure crystalline spinel LiMn
2
O
4
with small particle size and lower lattice strain. The thermogravimetric analysis threw the light on the role of the evaporation technique in producing LiMn
2
O
4
by following the different phases on the thermal performance of the precursor. The morphological characterization shows the clear appearance of the octahedral particles of LiMn
2
O
4
calcined at high temperature with microporous nanosized structure. Electrochemical testing of the as prepared spinel at 900 °C showed promising results in terms of high initial capacity and good cycle stability. The as prepared spinel sample shows also good rate performance.
“…According to the published results, the crystalline extent of LMO is the highest, while that of LFP is the lowest . As shown in Figure , LMO is the combination stack of LiO 4 tetrahedron and MnO 6 hexahedron elements in 3D scheme . In this structure, during the battery working process, Li + ions are transferred through 3D channel, that is, 8a‐16a‐8a.…”
Section: Resultsmentioning
confidence: 96%
“…With the rise of lithium technology, the market of electric devices also grows . To further develop high energy density and good cycle performance of lithium battery, many researches have been done to find out new electrode materials . Most of the research efforts focus on experimental synthesis of new electrode materials and design of novel structures.…”
Section: Introductionmentioning
confidence: 99%
“…In addition, it is earth‐abundant, inexpensive, non‐toxic, making it a strong candidate to replace LiCoO 2 . However, its main disadvantage is low overall capacities and cycle performance, because of the dissolution of Mn ion into the electrolyte and structural distortion . Therefore, it still needs some improvement to become commercialized.…”
For decades, lithium batteries have attracted much attention. Highly efficient, safe, and convenient batteries are worthy of being investigated and applied in modern life. However, most of the investigation is on the macroscopic device electrical properties such as current-voltage curves. Investigation on the microscopic electrical properties including potential distribution, electrolyte salt concentration distribution, and lithium ion concentration distribution within the batteries during the discharging is still needed. Here, a detailed study of the key electrical properties distributions inside the lithium battery in the discharging status is given. After comparing three widely used cathode materials (LiCoO 2 , LiMn 2 O 4 , and LiFePO 4 ), LiFePO 4 is found to show the most stable working performance which is consistent with previous reports. This is probably attributed to its most uniform key electrical properties distributions, its high electric conductivity, and crystal structure. A structure is also proposed which might give a hint to stress and temperature release for a longer and safer application of batteries. This simulation study on the key parameters distribution inside the battery may help to achieve a better understanding and hence control on the lithium battery performance and reliability.
“…When used as a cathode in a Li-ion battery, this material exhibits outstanding electrochemical performance of 165.3 mAh g −1 at 0.1 C and 92.6% retention after 40 cycles. As for manganates, Duan et al synthesized the LiMn 2 O 4 hollow nanofibers with a porous structure by modified electrospinning techniques on the fluorine-doped tin oxide glass [46]. The cathode made of these hollow materials delivered a specific capacity of 125.9 mAh g −1 and a cycling performance of 105.2 mAh g −1 after 400 cycles at 0.1 C, which exhibited a good battery performance.…”
Section: Methods For Making 3d Porous Li-ion Battery Cathodesmentioning
Among many types of batteries, Li-ion and Li-S batteries have been of great interest because of their high energy density, low self-discharge, and non-memory effect, among other aspects. Emerging applications require batteries with higher performance factors, such as capacity and cycling life, which have motivated many research efforts on constructing high-performance anode and cathode materials. Herein, recent research about cathode materials are particularly focused on. Low electron and ion conductivities and poor electrode stability remain great challenges. Three-dimensional (3D) porous nanostructures commonly exhibit unique properties, such as good Li+ ion diffusion, short electron transfer pathway, robust mechanical strength, and sufficient space for volume change accommodation during charge/discharge, which make them promising for high-performance cathodes in batteries. A comprehensive summary about some cutting-edge investigations of Li-ion and Li-S battery cathodes is presented. As demonstrative examples, LiCoO2, LiMn2O4, LiFePO4, V2O5, and LiNi1−x−yCoxMnyO2 in pristine and modified forms with a 3D porous structure for Li-ion batteries are introduced, with a particular focus on their preparation methods. Additionally, S loaded on 3D scaffolds for Li-S batteries is discussed. In addition, the main challenges and potential directions for next generation cathodes have been indicated, which would be beneficial to researchers and engineers developing high-performance electrodes for advanced secondary batteries.
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