Abstract
Silicon micropillars with tunable sizes are successfully fabricated on copper foils by using nanosecond-pulsed laser irradiation and then used as anodes for lithium-ion batteries. The size of the silicon micropillars is manipulated by using different slurry layer thicknesses ranging from a few microns to tens of microns. The effects of the pillar size on electrochemical properties are thoroughly investigated. The smaller the pillars, the better the electrochemical performance. A capacity of 1647 mAh g−1 at 0.1 C current rate is achieved in the anode with the smallest pillars, with 1215, 892, and 582 mAh g−1 at 0.2, 0.5, and 1.0 C, respectively. Although a significant difference in discharge capacity is observed in the early period of cycling among micropillars of different sizes, this discrepancy becomes smaller as a function of the cycle number. Morphological studies reveal that the expansion of micropillars occurred during long-term cycling, which finally led to the formation of island-like structures. Also, the formation of a solid electrolyte interphase film obstructs Li+ diffusion into Si for lithiation, resulting in capacity decay. This study demonstrates the importance of minimizing the pillar size and optimizing the pillar density during anode fabrication.
Highlights
IntroductionEver since Sony Corporation first commercialized lithium-ion batteries (LIBs) in 1991, LIBs have played a critical role in enabling the emergence of electric vehicles (EVs) and the widespread availability of portable electronic devices such as laptops, smartphones, and video cameras [1,2,3,4,5,6,7].graphite, as the anode material of traditional LIBs, has almost reached its performance limit for energy storage, and increasing the specific capacity of the anode material remains a challenge [8,9,10,11,12,13,14]
It can be seen that the as-received Si powders had an inherently irregular morphology,with with the thesize sizehaving havingaawide widerange range from fromaafew fewsub-microns sub-micronsto toover over10
Si micropillars with various sizes were successfully fabricated from Si waste powder via nanosecond-pulsed laser irradiation for fabricating lithium-ion battery anodes
Summary
Ever since Sony Corporation first commercialized lithium-ion batteries (LIBs) in 1991, LIBs have played a critical role in enabling the emergence of electric vehicles (EVs) and the widespread availability of portable electronic devices such as laptops, smartphones, and video cameras [1,2,3,4,5,6,7].graphite, as the anode material of traditional LIBs, has almost reached its performance limit for energy storage, and increasing the specific capacity of the anode material remains a challenge [8,9,10,11,12,13,14]. Silicon has been considered a promising anode candidate due to its low lithium-uptake potential (
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