Desired crystal oriented LiFePO₄nanoplatelets in situ anchored on a graphene cross-linked conductive network for fast lithium storage

Abstract

Electron transfer and lithium ion diffusion rates are the key factors limiting the lithium ion storage in anisotropic LiFePO4 electrodes. In this work, we employed a facile solvothermal method to synthesize a "platelet-on-sheet" LiFePO4/graphene composite (LFP@GNs), which is LiFePO4 nanoplatelets in situ grown on graphene sheets with highly oriented (010) facets of LiFePO4 crystals. Such a two-phase contact mode with graphene sheets cross-linked to form a three-dimensional porous network is favourable for both fast lithium ion and electron transports. As a result, the designed LFP@GNs displayed a high rate capability (∼56 mA h g(-1) at 60 C) and long life cycling stability (∼87% capacity retention over 1000 cycles at 10 C). For comparison purposes, samples ex situ modified with graphene (LFP/GNs) as well as pure LiFePO4 platelets (LFP) were also prepared and investigated. More importantly, the obtained LFP@GNs can be used as a basic unit for constructing more complex structures to further improve electrochemical performance, such as coating the exposed LFP surface with a thin layer of carbon to build a C@LFP@GN composite to further enhance its cycling stability (∼98% capacity retention over 1000 cycles at 10 C).

Solvothermal synthesis of LiFePO 4 nanorods as high-performance cathode materials for lithium ion batteries

“…The determined data vary from 6.8 Â 10 À 12 to 3.6 Â 10 À 11 cm 2 s À 1 , which are similar to the reported values for LiFePO 4 /C nanoparticles [39,40]. Among three samples, the LFP/C-9 shows the largest Li þ ions diffusion rate.…”

Synthesis of NiMoSO/rGO Composites Based on NiMoO4 and Reduced Graphene with High‐Performance Electrochemical Electrodes

“…Meanwhile, according to the TEM image of the NiMoSO/rGO‐b (Figure H ‐ Figure L), it also can be seen that there is a high contrast between the graphene sheet and the NiMoSO, which indicate the ultrathin thickness of graphene sheet, and also confirms its morphology. There are also the FESEM images of NiMoSO/rGO10% synthesized by another route and NiMoO 4 /rGO with different rate of rGO and in Figure S2 and Figure S3, respectively ,…”

Olivine Positive Electrodes for Li-Ion Batteries: Status and Perspectives

“…However, in this competition to obtain the best electrochemical performance, LFP/graphene has recovered an advantage with recent results. LiFePO 4 nanoplatelets with highly oriented (010) facets in situ grown on graphene sheets cross-linked to form a three-dimensional (3D) porous network displayed the same initial capacity of 121 mAh g −1 at 10 C, with an improved 98% capacity retention over 1000 cycles at this high charge rate [65] (see Figure 3). In this case, the weight fraction of graphene was 8.63 wt %.…”