Optimization of LiCoO2 Thick Electrodes with Low Tortuosity for Lithium-Ion Batteries by 3D Printing

Abstract

With the growing demand for high-energy-density and fast-charging lithium-ion batteries (LIBs), the ordered thick electrode structures and innovative 3D printing techniques have emerged as promising strategies. In this work, the electrochemical performance of LiCoO2 (LCO) electrodes with an exceptionally high active material content of 95 wt.% and significant thickness (~200 μm) in an ordered array structure was investigated. Direct ink writing (DIW) 3D printing was used to fabricate electrodes with varying sparse density (30%, 40%, 50%, and 60%). At a charge/discharge rate of 2 C, the specific capacity of the electrodes are 137.4, 138.4, 123.2, and 109.2 mAh g-1, respectively. The results demonstrated that the ordered array structure effectively mitigated the adverse effects of the increased thickness of the electrode by shortening the lithium-ion diffusion path and alleviating concentration polarization in both liquid and solid phases. Notably, this work introduced a novel approach to understanding the electrochemical performance of thick electrodes with a combination of electrochemical impedance spectroscopy (EIS) and electrochemical simulations to provide a comprehensive evaluation of ion transport mechanisms. The integration of thick electrode technology with 3D printing presented a promising pathway for the development of high energy density LIBs.