A study of the effects of synthesis conditions on Li5FeO4/carbon nanotube composites

Abstract

Li5FeO4/carbon nanotube (LFO/CNT) composites composed of sub-micron sized LFO and a nanocarbon with high electrical conductivity were successfully synthesized for the use as lithium ion predoping source in lithium ion cells. The phase of LFO in the composite was found to be very sensitive to the synthesis conditions, such as the heat treatment temperature, type of lithium salt, and physical state of the precursors (powder or pellet), due to the carbothermic reduction of Fe3O4 by CNTs during high temperature solid state reaction. Under optimized synthesis conditions, LFO/CNT composites could be synthesized without the formation of impurities. To the best of our knowledge, this is the first report on the synthesis and characterization of a sub-micron sized LFO/CNT composites.

Nano-Fe3O4/Carbon Nanotubes Composites by One-Pot Microwave Solvothermal Method for Supercapacitor Applications

“…These results match well with the magnetite Fe3O4 (JCPDS card No. 19-629) [19,26,27]. The XRD pattern for Fe3O4/CNT also shows the presence of CNT, which was clearly confirmed from the broad peak of (200) located at 25.4°.…”

“…SEM and low-magnification TEM images show that the iron oxide nanoparticles grew properly onto CNT bundles with a diameter of approximately 25 nm (Figure 2a-c and Figure S2a,b). The selected area electron diffraction (SAED) pattern of Fe3O4/CNT exhibits distinct diffraction rings corresponding to the (440), (400), (311), and (220) crystalline planes of Fe3O4, identifying that the highly crystalline Fe3O4 nanoparticles grew on the CNT (Figure 2d) [19,26,27]. As shown in Figure 2e, the TEM image displays the size of iron oxide nanoparticles grown uniformly on CNT ranges from 2 to 4 nm.…”

“…The metal oxide electrode can store charges by the faradic redox reaction, which shows higher specific capacitance, called pseudocapacitance [14][15][16][17][18]. Especially, magnetite (Fe 3 O 4 ) has gained significant attention as a pseudocapacitive electrode owing to its large theoretical capacitance, natural abundance, low cost, and eco-friendliness [19][20][21][22][23].…”

Practical evaluation of prelithiation strategies for next‐generation lithium‐ion batteries

“…With high capacity (greater than 600 mAh g −1 ) and suitable delithiation potential (3.5-4.0 V), Li 5 FeO 4 (LFO) showed excellent prelithiation ability as a cathode additive. [56][57][58][59][60] Lu et al added 7 wt% LFO to the LiCoO 2 cathode to increase the reversible capacity of the LiCoO 2 ||HC fullcell from 126 to 144 mAh g −1 , resulting in a significant increase in energy density. 61 To improve the electronic conductivity of LFO and lower its charging potential, Kim et al used an Fe 3 O 4 /CNT nanocomposite as the raw material to prepare LFO/CNT composites.…”

“…61 To improve the electronic conductivity of LFO and lower its charging potential, Kim et al used an Fe 3 O 4 /CNT nanocomposite as the raw material to prepare LFO/CNT composites. 60 Moreover, it should be mentioned that LFO is also sensitive to moisture, 59 which poses a challenge for slurry mixing as well as subsequent processes. Similar to LFO, Li 6 CoO 4 is a lithium-rich material with an anti-fluorite structure.…”