Abstract
In this work, we present a comprehensive and systematic study on the use of low-cost and highly abundant carbon precursors to obtain SiO2/C anodes with superior electrochemical performance towards Li-ions. Different SiO2/C composites are prepared by soaking silica nanoparticles in solutions containing 20 wt%, 40 wt%, or 60 wt% of glucose, sucrose, or cornstarch, followed by thermal decomposition of the carbohydrates at 850 °C or 1200 °C. Structural, microstructural, and textural differences on the composites derived from the different carbon coating treatments are related to the electrochemical performance of the anodes. Composites containing final carbon contents close to 15 wt% show a complete coverage of the SiO2 particles with a nanometric carbon layer and exhibit the best electrochemical results. The increase in the annealing temperature from 850 to 1200 °C reduces the porosity of the carbon layer and increases its level of ordering, both having positive effects on the overall electrochemical performance of the electrodes. SiO2/C composites coated with 40 wt% sucrose and heat treated at 1200 °C display the best electrochemical performance, delivering a reversible specific capacity of 723 mAhg−1 at 50 mAg−1 after 100 cycles, which is considerably higher than the reversible capacity of 233 mAhg−1 obtained with the uncoated material cycled under the same conditions.
Highlights
Li-ion batteries (LIBs) displaying high power and energy densities are in great demand for a wide variety of energy storage applications, ranging from portable electronics and electric vehicles to grid-level energy storage
For a given carbon precursor amount, composites coated with glucose and sucrose display similar micropore and external surface area values, whereas composites coated with cornstarch exhibit significantly lower values
Despite the differences observed when cycling at low current rates, the results show that at high currents, materials with glucose- and sucrose-based coatings (G40@1200 and S40@1200) display a more similar performance in comparison with composites heat treated at 850 °C, indicating that a higher annealing temperature is required for the glucose precursor to develop a well-structured coating
Summary
Li-ion batteries (LIBs) displaying high power and energy densities are in great demand for a wide variety of energy storage applications, ranging from portable electronics and electric vehicles to grid-level energy storage. To compare the electrochemical performance of composites coated with different amounts of carbon precursor, Fig. 5a displays the lithiation-specific capacity and Coulombic efficiency as a function of cycle number of electrodes made of S20@850, S40@850, and In order to demonstrate the importance of the activation procedure in diminishing the climbing capacity behavior of silica anodes, an electrode made of S40@850 composite was subjected to a first lithiation-delithiation step at 10 mAg−1, followed by galvanostatic cycling at 50 mAg−1.
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
