Laser Etching Post‐Processing to Create Low‐Tortuosity Structured Electrodes for Advanced Sodium‐Ion Batteries

Constructing low‐tortuosity structure is a facile and effective strategy to significantly improve the electrochemical performances of thick electrodes of batteries. In this study, the low‐tortuosity structured electrodes with an array grooved structure are fabricated using a method of laser etching post‐processing, promoting excellent electrochemical performance of sodium‐ion batteries (SIBs). The effects of laser post‐processing parameters including the etching shape, interval, and scan number on the structures and electrochemical performances of the prepared electrodes are investigated. Results show that the array grooved structures of the laser‐treated electrodes not only reduce the tortuosity to enhance the ion transfer efficiency, but also provide extra space to accommodate more electrolyte, which helps strengthen the electrochemical reaction kinetics of the electrodes. The proposed electrode with a parallelogram etching shape, an interval of 0.1 mm, and a scan number of 10 can produce a high rate capacity of 120.7 mAh g −1 at 500 mA g −1 and an outstanding cycle performance with a high capacity maintenance rate of 97.8% after 200 cycles. This study validates a new method to create low‐tortuosity electrodes for SIBs by optimizing the process parameter, which can be potentially extended to the fabrication of other advanced energy storage devices.