Direct formation of LiFePO4/graphene composite via microwave-assisted polyol process
| Autor: | Jaekook Kim, Sungjin Kim, Jihyeon Gim, Jinsub Lim, Dang Thanh Nguyen, Vinod Mathew, Jinju Song, Jeonggeun Jo |
|---|---|
| Rok vydání: | 2016 |
| Předmět: |
Nanocomposite
Materials science Renewable Energy Sustainability and the Environment Graphene Composite number Energy Engineering and Power Technology Nanoparticle Graphite oxide Nanotechnology 02 engineering and technology 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences Nanocrystalline material Lithium-ion battery 0104 chemical sciences law.invention chemistry.chemical_compound Crystallinity Chemical engineering chemistry law Electrical and Electronic Engineering Physical and Theoretical Chemistry 0210 nano-technology |
| Zdroj: | Journal of Power Sources. 304:354-359 |
| ISSN: | 0378-7753 |
| Popis: | The present study reports on the direct synthesis of LiFePO 4 nanoparticles and graphene nanosheets to form a composite cathode (LFP/GNs) in a one-step microwave-assisted polyol reaction. The polyol reaction induced by microwave irradiation for a few minutes produces nanocrystalline LFP and graphene nanosheets simultaneously from lithium, iron and phosphorus and carbon (5 wt% of graphite oxide) sources, respectively, used as starting precursors. Powder X-ray diffraction (XRD), electron microscopy, and atomic force microscopy (AFM) studies on microwave-reacted sample obtained using just graphite oxide confirms the formation of graphene nanosheets separately. Whereas, electron microscopy studies on the LFP/GNs composite reveals that olivine nanoparticles of average sizes ranging between 5 and 20 nm are well-dispersed on the graphene nanosheets. Electrochemical measurements reveal that the LiFePO 4 /GNs nanocomposite cathodes registered enhanced discharge capacities (79 and 108 mAh g −1 for the as-prepared and annealed composite cathodes, respectively) at 32 C rates with good capacity retention capabilities. The AC impedance measurements confirm that the enhanced cathode properties of the LFP/GNs nanocomposite are ascribed to the improved electronic conductivity of the graphene nanosheets and the nano-sized particles. The slightly better electrochemical properties of the annealed LFP/GNs are attributed to its higher crystallinity. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full Text from ScienceDirect