In-situ self-polymerization restriction to form core-shell LiFePO4/C nanocomposite with ultrafast rate capability for high-power Li-ion batteries

Self‐Assembly of Antisite Defectless nano‐LiFePO4@C/Reduced Graphene Oxide Microspheres for High‐Performance Lithium‐Ion Batteries

“…Detailed structural information of surface residual carbon was further verified by means of Raman spectroscopy (Figure S15 in the Supporting Information) . Typically, an increase in the intensity ratio of G and D bands ( I G / I D ) in the Raman spectrum is an indicator of a greater degree of ordering for graphitic materials . According to the fitting result, the I G / I D value of LiFePO 4 @C/rGO was estimated to be 0.82, which is similar to or higher than those of most LiFePO 4 /C modified with other types of semigraphitized carbon; this implies that residual carbon pyrolyzed from the RF polymer and GO is more graphitized, and thus, capable of providing better electrical transfer around LiFePO 4 nanoparticles.…”

“…A Fe . Li antisite defect, namely, an Fe 2+ ion occupying the Li + site, is commonly observed in LiFePO 4 crystals, and it is proven to be unfavorable due to blocking of the Li + diffusion pathway . The content of Fe .…”

“…From a topological point of view, the superior electrochemical performance of LiFePO 4 @C/rGO can be derived from the unique hierarchical composite structure of the LiFePO 4 OH@RF/GO precursor, which is formed from fully sealing RF resin polymer “shells” with a spherical 3D‐connected network and single‐source inorganic LiFePO 4 OH “cores”, in which the ideal elements of Li, Fe, P, and O are evenly distributed at the atomic level; thus are capable of minimizing the formation of undesired impurities and Fe . Li lattice defects for LiFePO 4 obtained, owing to the absence of complex crystallographic phase transitions and long‐range solid–solid mass‐transfer processes upon crystallization . In addition, ultrathin rGO nanosheets anchored on the surface can establish a continuous and robust conductive network for interparticle electrical connection to lower the soft contact impedance .…”

“…The LiFePO 4 nanocrystals were coated with a layer of amorphous carbon with a typical thickness of about 2.0 nm. Generally speaking, the kinetic barrier for Li + ions to diffuse through such a thin carbon layer can be totally neglected, in contrast to other diffusion kinetic limitations, upon cycling . The mass fraction of carbon contained in the particles was determined by CHN elemental analysis to be about 6 wt %.…”

Coating LiFePO4 with Conductive Nanodots by Magnetron Sputtering: Toward High‐Performance Cathode for Lithium‐Ion Batteries

“…For example, Rong et al synthesized nano LFP with a highest capacity of 166.9 mAh g −1 at 0.1 C using nano Fe 2 O 3 as raw materials . Wang et al fabricated core‐shell LFP, which can reach a complete discharge at a rate of 150 C with a specific capacity of 95.4 mAh g −1 . Wang et al reported an LFP quantum‐dots composite with a high rate capability of 78 mAh g −1 at 200 C .…”