Three-dimensional cathode with periodically aligned microchannels for improving volumetric energy density of lithium-ion batteries

Abstract

Increasing the thickness of electrodes of lithium-ion batteries (LIBs) is an effective method for improving the volumetric energy density by reducing the inactive materials (e.g., current collector and separator) in LIBs. However, the thickening of conventional electrodes results in poor capacity due to inefficient transport of Li ions through the irregular microstructure of the electrode. To solve this problem, herein, a new three-dimensional (3D) LiCoO2 (LCO) cathode with periodically aligned microchannels is presented to improve the volumetric energy density of LIBs. The sub-millimeter-thick 3D LCO is fabricated successfully by the ceramics process, which includes lamination of LCO/graphite sheets followed by co-sintering. The 3D LCO demonstrates an excellent areal capacity and rate capability at high rates (31 and 12.1 mAh cm−2 at 0.1 and 1 C, respectively) because of the constant intervals of the microchannels and a low tortuosity value of 1. Moreover, the electrode density of the 3D LCO is similar to that of a conventional LCO, which enables the improvement of the volumetric energy density. A 3D LCO-Li cell achieves a volumetric energy density of up to 1.8 kW h L−1, which is 50% higher than that of a conventional LCO-Li cell.