Ballistic electrolyte ion transport with undisturbed pathways for ultrahigh-rate electrochemical energy storage devices

Abstract

The efficient charge–discharge process in electrochemical energy storage devices is hinged on the sluggish kinetics of ion migration inside the layered/porous electrodes. Despite the progress achieved in nanostructure configuration and electronic properties engineering, the electrodes require a fluent pathway in the mesoscopic structure to avoid ion accumulation during the (de)intercalation processes. Herein, we carefully designed and validated a robust way of generating long regular channels in electrodes through experiments and density functional theory (DFT) calculations to enhance ion transport efficiency with the prototype of a two-dimensional conjugated metal–organic framework (2D c-MOF). The AA-stacking c-MOF electrode delivers a high areal capacitance (28.7 F cm⁻² at 0.2 mV s⁻¹) with a retained capacitance of 15.9 F cm⁻² after the charge–discharge rate increases by 50 times, revealing the ultrafast ion kinetics, while the AB-stacking MOF electrode exhibits a capacitance retention of 17.5% (from 16 F cm⁻² to 2.8 F cm⁻²).