Efficient Preparation of Li<sub>2</sub>FeSiO<sub>4</sub>/C with High Purity and Excellent Electrochemical Performance in Li-Ion Batteries
One method to enhance the electrochemical performance of carbon-coated Li<sub>2</sub>FeSiO<sub>4</sub> cathode material in lithium-ion batteries is to produce an ideal Li<sub>2</sub>FeSiO<sub>4</sub> precursor with minimal impurities. A novel precursor...
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| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2025-02-01
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| Series: | Molecules |
| Subjects: | |
| Online Access: | https://www.mdpi.com/1420-3049/30/4/808 |
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| Summary: | One method to enhance the electrochemical performance of carbon-coated Li<sub>2</sub>FeSiO<sub>4</sub> cathode material in lithium-ion batteries is to produce an ideal Li<sub>2</sub>FeSiO<sub>4</sub> precursor with minimal impurities. A novel precursor for Li<sub>2</sub>FeSiO<sub>4</sub> (Li<sub>2</sub>O·FeCO<sub>3</sub>·CH<sub>3</sub>OSiO<sub>2</sub>H) was synthesized through a methanol solvothermal reaction under stringent conditions (180 °C and 2.7 MPa), achieving a purity level of 93.2%. During synthesis, the new Li<sub>2</sub>FeSiO<sub>4</sub> precursor exhibits unique self-purification properties and maintains a fine morphology after annealing. The resulting carbon-coated Li<sub>2</sub>FeSiO<sub>4</sub> composites demonstrate a Brunauer–Emmett–Teller specific surface area of 102.4 m<sup>2</sup>/g and approximately 81% mesoporous volume, with 90% of the pore sizes measuring less than 39 nm. As a cathode material for lithium-ion batteries, this carbon-coated Li<sub>2</sub>FeSiO<sub>4</sub> exhibits initial specific capacities of 172.3 mAh/g (charge) and 159.3 mAh/g (discharge). Remarkably, nearly 50% of the theoretical specific capacity remains after 1300 cycles at a rate of 0.1 C. The excellent electrochemical performance of the carbon-coated Li<sub>2</sub>FeSiO<sub>4</sub> materials is demonstrated by their high lithium-ion diffusivity (D<sub>Li+</sub>) value of 1.26 × 10<sup>−11</sup> cm<sup>2</sup>/s. Additionally, the enormous capacities-controlled diffusion contribution, which accounts for 70% of the total diffusion at a rate of 1C, is noteworthy. This performance can be attributed to the high purity of the carbon-free Li<sub>2</sub>FeSiO<sub>4</sub> composite, which contains 91% Li<sub>2</sub>FeSiO<sub>4</sub>, as well as its favorable morphology. |
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| ISSN: | 1420-3049 |