Lityum-iyon bataryalar için elektro eğirme yöntemiyle üretilmiş carbon nanolif tabanlı kompozit anot malzemeleri

Among the various currently-used rechargeable battery technologies, rechargeable lithium-ion batteries are considered as the most promising rechargeable batteries in recent years because of their distinguished properties such as high energy density, long cycle life, good thermal stability, no memory effect and good power performance. Exploring high-capacity electrode materials for lithium-ion batteries is crucial for technological improvements on mobile electronic devices, large-scale smart grids and electric vehicle technologies using lithium-ion batteries as the power source. Current commercial lithium-ion batteries use graphitic materials in the anode. However, the theoretical capacity (372 mAh g−1) of graphitic anode materials cannot meet the ever-growing capacity requirements of future portable electronics and electric vehicle technologies. Lithium storage capacities of alloy-type anodes (e.g., silicon, tin, germanium, and their oxides) are much higher than that of currently used intercalation-type graphite anode. Among different alloy-type anodes, Si and tin dioxide (SnO2) are considered as the most promising candidates for next-generation lithium-ion batteries because of their high gravimetric and volumetric capacities. In this work, we focused on fabricating novel composite nanofibers and exploring their potential applications as anode materials for new-generation, high-performance rechargeable lithium-ion batteries. In one of the studies, we introduced carbon-enhanced binder-free SnO2-electrodeposited carbon nanofibers (CNF@SnO2) and SnO2-electrodeposited porous carbon nanofiber (PCNF@SnO2) composites that can sustain their structural stability during repeated charge-discharge cycling. Combination of porous nanofiber structure and nanoscale carbon confinement led to a novel carbon-coated PCNF@SnO2 composite anode with high capacity retention and large coulombic efficiency. In another study, novel carbon-confined polyviniyl alcohol (PVA)-derived silicon/silica/carbon nanofiber composite anodes with improved electrochemical performance were successfully fabricated for high-capacity lithium-ion batteries. High-energy, flexible lithium-ion batteries become critically important with technological improvements on portable and bendable electronic equipment such as rollup displays, implantable medical devices, active radio-frequency identification tags, and wearable devices. Hence, we introduced flexible silicon/silica/carbon (Si/SiO2/C) nanofiber composite anode materials with superior electrochemical performance for next-generation flexible and high-energy lithium-ion batteries. We also introduced nanoscale silica-coated silicon/carbon (Si@C-SiO2) nanofiber composites that can maintain their structural stability during repeated cycling. Nanoscale SiO2 coating of Si@C nanofibers helped preserve the Si particles within the nanofiber structure, resulting in stable solid electrolyte interphase formation and improved cycling performance. Results indicate that novel composite nanofiber anodes with increased reversible capacity and enhanced capacity retention were successfully developed for next-generation lithium-ion batteries. Hopefully, introduced anode designs will open up new opportunities to develop high-performance electrode materials for next-generation lithium-ion batteries, which are the outstanding energy storage systems for addressing the developing challenge of the sustainable energy sources and reducing the consumption of fossil fuels.