Tortuosity\nEngineering for Improved Charge Storage\nKinetics in High-Areal-Capacity Battery Electrodes

Abstract

The increasing demands of electronic devices and electric\ntransportation\nnecessitate lithium-ion batteries with simultaneous high energy and\npower capabilities. However, rate capabilities are often limited in\nhigh-loading electrodes due to the lengthy and tortuous ion transport\npaths with their electrochemical behaviors governed by complicated\nelectrode architectures still elusive. Here, we report the electrode-level\ntortuosity engineering design enabling improved charge storage kinetics\nin high-energy electrodes. Both high areal capacity and high-rate\ncapability can be achieved beyond the practical level of mass loadings\nin electrodes with vertically oriented architectures. The electrochemical\nproperties in electrodes with various architectures were quantitatively\ninvestigated through correlating the characteristic time with tortuosity.\nThe lithium-ion transport kinetics regulated by electrode architectures\nwas further studied via combining the three-dimensional electrode\narchitecture visualization and simulation. The tortuosity-controlled\ncharge storage kinetics revealed in this study can be extended to\ngeneral electrode systems and provide useful design consideration\nfor next-generation high-energy/power batteries.