Processing of a Large‐Scale Microporous Group on Copper Foil Current Collectors for Lithium Batteries Using Femtosecond Laser

Abstract

Due to the thin thickness (≈8 μm) and soft nature of copper foil current collectors, it is extremely difficult to process large‐scale micro–nano holes on their surface. In this study, trepanning drilling of a copper foil current collector with a 1030 nm femtosecond laser system is investigated with emphasis on developing the processing technology of copper foil current collectors with different entry and exit sizes while maintaining good hole quality. The effects of laser parameters on the processing quality of copper foil current collectors are comprehensively studied. The relationship between geometric morphology and processing parameters as well as the formation mechanism is fully discussed. The smallest hole taper is found at a defocusing amount of −1.8 mm. Consequently, a group of holes with 250 000 micropores is obtained on a (2 cm × 2 cm) current collector, demonstrating the high efficiency and high quality of femtosecond laser‐based processing. Half‐cells with a modified current collector operate with a more stable response than half‐cells with unmodified copper foil at cycle performance and rate performance.

Laser ablation in air and its application in catalytic water splitting and Li-ion battery

“…In another example, micro holes on copper foil are fabricated in large scale utilizing LAA method to achieve more stable current collectors for lithium batteries ( Li et al., 2020 ). Current collectors exhibit high importance in Li-ion batteries, which not only carry the electrode material but also collect electrical current when the battery functionalizes.…”

“… (C) Cycle performance and the corresponding rate capability of half-cells with two types of Cu current collectors. Figures adopted from ( Li et al., 2020 ) with permission. …”

“… Figures adopted from ( Li et al., 2020 ) with permission. …”

Lightweight Through-Hole Copper Foil as a Current Collector for Lithium-Ion Batteries

“…As a result, the anode active material tends to shed from the Cu current collector during a long period of services, causing an increase in internal resistance and a decrease in cyclic performance . Therefore, rational structure design of Cu foil is an effective way to reduce its weight and to improve the adhesion to the active materials so as to enhance the specific capacity and cyclic performance of LIBs. , …”

“…14 Therefore, rational structure design of Cu foil is an effective way to reduce its weight and to improve the adhesion to the active materials so as to enhance the specific capacity and cyclic performance of LIBs. 15,16 A variety of methods have been reported to fabricate current collectors with modified surface structures. Many studies focus on the preparation of complex micro-and nanostructures.…”