Rechargeable lithium-ion batteries have made a tremendous impact on our society, they became ubiquitous energy storage devices in portable electronics such as mobile phones, laptops, digital cameras, and other electronic device. Furthermore, because of their performance and increasing concern and co...
Rechargeable lithium-ion batteries have made a tremendous impact on our society, they became ubiquitous energy storage devices in portable electronics such as mobile phones, laptops, digital cameras, and other electronic device. Furthermore, because of their performance and increasing concern and commitment of the people to environmental sustainability, the lithium-ion batteries (LIBs) are regarded as the technology of choice for next-generation energy storage systems for powering all-electric vehicles (hybrid and plug-in hybrid electric vehicles).
High specific capacity, high energy density, high charge rate and discharge power, long cycle-life, and ensured safety are essential for enabling the widespread practical implementations of the LIBs in electric vehicles (EVs). To date, most of the commercial LIBs use graphite as an anode, which has a theoretical capacity of 372 mAh g-1. Despite, it cannot meet the high energy goals of high capacity and high energy density for advanced energy storage applications. In this regard, silicon has been considered as one of the most promising anode materials owing to its low discharge potential, high theoretical specific capacity of ~4200 mAh g-1 (at fully lithiated state Li22Si5)), non-toxicity and natural abundance. However, the Si-based LIBs have been stymied by the severe volume changes (volume expansion/contraction) about 400% occurred during the alloying/de-alloying (lithiation/delithiation) of Si with Li. These inevitable spontaneous volume changes develop huge stresses and strains within the electrode leading to the pulverization of the electrode material and unstable SEI (solid electrolyte interface) formation, which causes loss of inter particle electrical contacts results in degradation of the battery performance.
In this work, different synthesis approaches (high-energy mechanical milling, pyrolysis, low temperature thermal oxidation and induction melting processes) employed for generating the nanoscale Si and/or Si based composite structures, such as silicon/carbon (Si/C) nanocomposite, surface oxide-modulated Si-graphite (Si/SiOx and Si/SiOx@C) nanocomposite and core-shell structured surface oxide@slicon-silicide (SiOx@Si-FeSi2) nanocomposite are discussed. Their electrochemical behavior has been analyzed and correlated to the synthesis process, ensuing structural changes, related structural and microstructural property, degradation mechanism and finally their performance. The Si anodes were characterized for their structure, microstructure and electrochemical performance (first cycle irreversible loss, specific charge–discharge capacities, and fade rate) in Li/Li+ system. Their behavior was correlated to morphology of nanostructures before and after electrochemical cycling, and process parameters employed during the synthesis process. X-ray diffraction, PSA, SEM/TEM, TGA analysis, Raman spectroscopy, and XPS have been used to characterize the crystallographic structure and composition of these nanostructures before and after electrochemical cycling to confirm the evolution, phase and morphological stability of these nanostructures.
Rechargeable lithium-ion batteries have made a tremendous impact on our society, they became ubiquitous energy storage devices in portable electronics such as mobile phones, laptops, digital cameras, and other electronic device. Furthermore, because of their performance and increasing concern and commitment of the people to environmental sustainability, the lithium-ion batteries (LIBs) are regarded as the technology of choice for next-generation energy storage systems for powering all-electric vehicles (hybrid and plug-in hybrid electric vehicles).
High specific capacity, high energy density, high charge rate and discharge power, long cycle-life, and ensured safety are essential for enabling the widespread practical implementations of the LIBs in electric vehicles (EVs). To date, most of the commercial LIBs use graphite as an anode, which has a theoretical capacity of 372 mAh g-1. Despite, it cannot meet the high energy goals of high capacity and high energy density for advanced energy storage applications. In this regard, silicon has been considered as one of the most promising anode materials owing to its low discharge potential, high theoretical specific capacity of ~4200 mAh g-1 (at fully lithiated state Li22Si5)), non-toxicity and natural abundance. However, the Si-based LIBs have been stymied by the severe volume changes (volume expansion/contraction) about 400% occurred during the alloying/de-alloying (lithiation/delithiation) of Si with Li. These inevitable spontaneous volume changes develop huge stresses and strains within the electrode leading to the pulverization of the electrode material and unstable SEI (solid electrolyte interface) formation, which causes loss of inter particle electrical contacts results in degradation of the battery performance.
In this work, different synthesis approaches (high-energy mechanical milling, pyrolysis, low temperature thermal oxidation and induction melting processes) employed for generating the nanoscale Si and/or Si based composite structures, such as silicon/carbon (Si/C) nanocomposite, surface oxide-modulated Si-graphite (Si/SiOx and Si/SiOx@C) nanocomposite and core-shell structured surface oxide@slicon-silicide (SiOx@Si-FeSi2) nanocomposite are discussed. Their electrochemical behavior has been analyzed and correlated to the synthesis process, ensuing structural changes, related structural and microstructural property, degradation mechanism and finally their performance. The Si anodes were characterized for their structure, microstructure and electrochemical performance (first cycle irreversible loss, specific charge–discharge capacities, and fade rate) in Li/Li+ system. Their behavior was correlated to morphology of nanostructures before and after electrochemical cycling, and process parameters employed during the synthesis process. X-ray diffraction, PSA, SEM/TEM, TGA analysis, Raman spectroscopy, and XPS have been used to characterize the crystallographic structure and composition of these nanostructures before and after electrochemical cycling to confirm the evolution, phase and morphological stability of these nanostructures.
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