Nanosized LiFePO4 Cathode Materials for Lithium Ion Batteries

2007 ◽  
Vol 7 (11) ◽  
pp. 3980-3984 ◽  
Author(s):  
Hal-Bon Gu ◽  
Dae-Kyoo Jun ◽  
Gye-Choon Park ◽  
Bo Jin ◽  
En Mei Jin

In this study, we prepared nano-particles of LiFePO4 as cathode material for lithium ion batteries by the solid-state reaction. A simple one-step heat treatment has been employed with control of heating temperature and heated LiFePO4 at 650 °C exhibited higher 125 mA h/g of the discharge capacity than 600 °C, 700 °C. To improve conductivity of the inter-particle, carbon coating was carried out by raw carbon or pyrene as carbon sources and their morphological properties of particles on the carbon coating was compared with by FE-SEM, TEM. From the FE-SEM results, the particles of carbon added LiFePO4 have much smaller size than LiFePO4 as below 300 nm. When adding pyrene (10 wt%), the carbon surrounded non-uniformly with surface of the particles compared with adding raw carbon which wrapped uniformly with carbon web and it was exhibited 152 mA h/g of the discharge capacity on LiFePO4/C composite cells at 10th cycle.

2011 ◽  
Vol 396-398 ◽  
pp. 1748-1754 ◽  
Author(s):  
Wen Kui Zhang ◽  
Bin Zhao ◽  
Yang Xia ◽  
Xiao Zheng Zhou ◽  
Hui Huang ◽  
...  

A new kind of cathode materials, Li3V2(PO4)3/C nanocomposites, has been prepared via one-step solid-state reaction using ultra low-cost asphalt as both reduction agents and carbon sources. The asphalt is contained 60.37% of fixed carbon and 0.18% of other impurity.It is purchased from Zhen jiang Xin Guang Metallurgical Subsidiary Material Plant. Structural analysis shows that the obtained Li3V2(PO4)3/C nanocomposites contain abundant Li3V2(PO4)3 nanorods and micro/nano particles encapsulate with carbon shells. The Li3V2(PO4)3/C nanocomposites achieve enhanced dischargeability, reversibility, and cycleability. Electrochemical tests show that the Li3V2(PO4)3/C nanocomposite has initial discharge capacities of 170 mAhg-1 at 0.1C in the voltage range of 3.0 to 4.8 V. The improved electrochemical properties of the Li3V2(PO4)3/C nanocomposites are attributed to the presence of Li3V2(PO4)3/C nanorods and the electronically conductive carbon shell. This one-step solid state reaction using low-cost asphalt as carbon sources is feasible for the preparation of the Li3V2(PO4)3/C nanocomposites which can offer favorable properties for commercial applications.


2017 ◽  
Vol 225 ◽  
pp. 350-357 ◽  
Author(s):  
Zhen Shen ◽  
Yi Hu ◽  
Renzhong Chen ◽  
Xia He ◽  
Yanli Chen ◽  
...  

Author(s):  
G. S. Zakharova ◽  
E. Thauer ◽  
A. N. Enyashin ◽  
L. F. Deeg ◽  
Q. Zhu ◽  
...  

AbstractThe potential battery electrode material V2O3/C has been prepared using a sol–gel thermolysis technique, employing vanadyl hydroxide as precursor and different organic acids as both chelating agents and carbon sources. Composition and morphology of resultant materials were characterized by X-ray diffraction, Raman spectroscopy, scanning and transmission electron microscopies, physical sorption, and elemental analysis. Stability and electronic properties of model composites with chemically and physically integrated carbon were studied by means of quantum-chemical calculations. All fabricated composites are hierarchically structured and consist of carbon-covered microparticles assembled of polyhedral V2O3 nanograins with intrusions of amorphous carbon at the grain boundaries. Such V2O3/C phase separation is thermodynamically favored while formation of vanadium (oxy)carbides or heavily doped V2O3 is highly unlikely. When used as anode for lithium-ion batteries, the nanocomposite V2O3/C fabricated with citric acid exhibits superior electrochemical performance with an excellent cycle stability and a specific charge capacity of 335 mAh g−1 in cycle 95 at 100 mA g−1. We also find that the used carbon source has only minor effects on the materials’ electrochemical performance.


2021 ◽  
Vol MA2021-01 (2) ◽  
pp. 124-124
Author(s):  
Shuo Zhou ◽  
Shan Fang ◽  
Chen Fang ◽  
Gao Liu

2016 ◽  
Vol 724 ◽  
pp. 87-91 ◽  
Author(s):  
Chang Su Kim ◽  
Yong Hoon Cho ◽  
Kyoung Soo Park ◽  
Soon Ki Jeong ◽  
Yang Soo Kim

We investigated the electrochemical properties of carbon-coated niobium dioxide (NbO2) as a negative electrode material for lithium-ion batteries. Carbon-coated NbO2 powders were synthesized by ball-milling using carbon nanotubes as the carbon source. The carbon-coated NbO2 samples were of smaller particle size compared to the pristine NbO2 samples. The carbon layers were coated non-uniformly on the NbO2 surface. The X-ray diffraction patterns confirmed that the inter-layer distances increased after carbon coating by ball-milling. This lead to decreased charge-transfer resistance, confirmed by electrochemical impedance spectroscopy, allowing electrons and lithium-ions to quickly transfer between the active material and electrolyte. Electrochemical performance, including capacity and initial coulombic efficiency, was therefore improved by carbon coating by ball-milling.


NANO ◽  
2018 ◽  
Vol 13 (09) ◽  
pp. 1850103 ◽  
Author(s):  
Xu Chen ◽  
Chunxin Yu ◽  
Xiaojiao Guo ◽  
Qinsong Bi ◽  
Muhammad Sajjad ◽  
...  

Novelty Cu2O multi-branched nanowires and nanoparticles with size ranging from [Formula: see text]15[Formula: see text]nm to [Formula: see text]60[Formula: see text]nm have been synthesized by one-step hydrothermal process. These Cu2O nanostructures when used as anode materials for lithium-ion batteries exhibit the excellent electrochemical cycling stability and reduced polarization during the repeated charge/discharge process. The specific capacity of the Cu2O nanoparticles, multi-branched nanowires and microscale are maintained at 201.2[Formula: see text]mAh/g, 259.6[Formula: see text]mAh/g and 127.4[Formula: see text]mAh/g, respectively, under the current density of 0.1[Formula: see text]A/g after 50 cycles. The enhanced electrochemical performance of the Cu2O nanostructures compared with microscale counterpart can be attributed to the larger contact area between active Cu2O nanostructures/electrolyte interface, shorter diffusion length of Li[Formula: see text] within nanostructures and the improved stress release upon lithiation/delithiation.


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