Structure, performance, morphology and component transformation mechanism of LiMn0·8Fe0·2PO4/C nanocrystal with excellent stability
| Autor: | Han Chen, Ting Luo, Run-zhen Fan, Changling Fan, Shaochang Han, Shi-lin Chen, Taotao Zeng, Rong Li |
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| Rok vydání: | 2020 |
| Předmět: |
Materials science
Mechanical Engineering Diffusion Metals and Alloys chemistry.chemical_element 02 engineering and technology 010402 general chemistry 021001 nanoscience & nanotechnology Electrochemistry 01 natural sciences 0104 chemical sciences Chemical engineering Nanocrystal chemistry Mechanics of Materials Materials Chemistry Chemical stability Lithium 0210 nano-technology Dissolution Stoichiometry Nanosheet |
| Zdroj: | Journal of Alloys and Compounds. 834:155143 |
| ISSN: | 0925-8388 |
| DOI: | 10.1016/j.jallcom.2020.155143 |
| Popis: | LiMn0·8Fe0·2PO4/C nanocrystal was synthesized by a facile solvothermal reaction. The pH and concentration of lithium ion are changing with the increase of LiOH. The deposition law of precursor ions is investigated, in which Li+ exceeds the necessary stoichiometric ratio even in the lowest amount of LiOH. Mn2+ and Fe2+ possess the similar fixation tendency, and 87.88% Mn2+ are deposited at the pH of 3.30. However, nearly all Fe2+ are precipitated in a wide pH range (2.96–3.85). The morphology changes from nanosheet to nanoellipsoid under the cooperation of pH and precursor ions. The components of LiMnPO4 and LiFePO4 in LiMn0·8Fe0·2PO4/C are predicted and their contributions to capacity are close to the actual results. Sample S-2.6 delivers the optimum electrochemical performance with a capacity of 150.9, 134.6 and 107.5 mA h·g−1 at 0.05, 1 and 5 C, respectively. It also exhibits high reversibility, low charge transfer resistance (41.2 Ω) and excellent diffusion coefficient (5.38 × 10−11 cm2·s−1). The capacity retention of sample S-2.6 reaches 96.03% after 200 cycles and it maintains original structure without obvious change according to the ex-situ XRD results. The morphology of the cycled cathode film also maintains its integrity without evident cracks. The low dissolution of Mn2+ and Fe2+ from LiMn0·8Fe0·2PO4/C shows the enhanced chemical stability. |
| Databáze: | OpenAIRE |
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