Electrochemical Analysis of Thick Electrode According to Laser Structuring Design for High Energy Density Lithium-ion Batteries

Abstract

Demands of high energy storage devices have been increasing. Thickening electrode is a practical and economical method because it can easily increase the cell energy density by reducing the inactive materials of the cell. However, a long lithium-ion transport pathway of thick electrode typically leads to many potential problems, such as high ionic resistance and high internal electrical resistance. An effective way to overcome these problems is to structure thick electrodes to form pathways through which lithium-ions can move easily. In this work, thick LiNi0.5Mn0.3Co0.2O2 cathode of 140 ＆mu;m was structured to form line-shaped grooves on the electrode surface using femtosecond laser. By investigating the optimal structuring design, the laser structured thick electrodes under various designs were electrochemically analyzed. Using galvanostatic method and electrochemical impedance spectroscopy, we obtained the improved electrochemical properties and performances of the laser structured cells compared to the unstructured cells. As a result, we confirmed performance enhancements in energy and power density at the laser structured cell. In addition, design parameters such as pitch and depth were observed as important factors of laser structuring.