Femtosecond laser dual modification of Si/C composite coating and Cu current collector for high-performance lithium-ion batteries

Silicon anodes are promising candidates for next-generation lithium-ion batteries owing to their high theoretical capacity. However, they suffer from severe delamination from Cu current collectors owing to massive volume expansion, leading to rapid capacity degradation. Herein, we introduce a femtosecond laser dual modification approach to comprehensively surface-treate both the Si/C composite coating and Cu current collector by Gaussian and linear beams. Benefiting from ultrashort pulses and high peak power, femtosecond laser enables precise, thermal-damage-free processing, thereby creating clear and complete surface structure on current collectors and coatings. The optimal modified electrode—SS-Si-LFG (linear beam-modified Si/C composite coating + Gaussian beam-modified Cu current collector)—achieves a high reversible specific capacity of 2200 mAh g −1 after 300 cycles at 0.1C, representing a 63% increase compared to the SS-Si electrode (1350 mAh g −1 ). The improvement in electrochemical performance can be attributed to the enhanced adhesion facilitated by the stripe structure on the Cu current collector, as well as the increased Li + transport efficiency resulting from the microstructure on the Si/C composite coating. The proposed femtosecond laser dual modification approach provides a novel pathway for the development of high-performance lithium-ion batteries.