Three-dimensionalization via control of laser-structuring parameters for high energy and high power lithium-ion battery under various operating conditions

Abstract

Laser-structuring is an effective method to promote ion diffusion and improve the performance of lithium-ion battery (LIB) electrodes. In this work, the effects of laser structuring parameters (groove pitch and depth) on the fundamental characteristics of LIB electrode, such as interfacial area, internal resistances, material loss and electrochemical performance, are investigated. LiNi0.5Co0.2Mn0.3O2 cathodes were structured by a femtosecond laser by varying groove depth and pitch, which resulted in a material loss of 5%–14% and an increase of 140%–260% in the interfacial area between electrode surface and electrolyte. It is shown that the importance of groove depth and pitch on the electrochemical performance (specific capacity and areal discharge capacity) of laser-structured electrode varies with current rates. Groove pitch is more important at low current rate but groove depth is at high current rate. From the mapping of lithium concentration within the electrodes of varying groove depth and pitch by laser-induced breakdown spectroscopy, it is verified that the groove functions as a diffusion path for lithium ions. The ionic, electronic, and charge transfer resistances measured with symmetric and half cells showed that these internal resistances are differently affected by laser structuring parameters and the changes in porosity, ionic diffusion and electronic pathways. It is demonstrated that the laser structuring parameters for maximum electrode performance and minimum capacity loss should be determined in consideration of the main operating conditions of LIBs.