We investigated the origin of the rapid capacity fading of the cathodes with the increasing electrode thickness in the Solid-state lithium-ion batteries, which stems from sluggish lithium diffusion in the solid-state electrolytes as a result of “sandwich” concentration gradients in the discharged electrode. With the help of 3D digital-twin electrodes and 4D-resolved simulations, an electrode scale irreversible-lithium model is firstly proposed, and an in situ photo-induced activation strategy enabled improved lithium diffusion in a high-loading electrode.

Abstract

In solid-state lithium-ion batteries, the fraction of active materials involved in electrode electrochemistry reduces with the increase of electrode thickness. Conventional wisdom suggests that the degree of reaction linearly decreases toward the current collector as in lithium-ion batteries, which is, however, limited by the high difficulty of experimental capture of operando charge and mass transport. Electrode dynamics simulations can provide space visualization but are usually based on simplified models. Herein, we build digital-twin electrodes with digital-space voxel microstructure based on synchrotron tomography, which transforms the electrode architecture from real space to digital space for the construction of precision models. From the digital model-driven simulation, we find an “lithium trapping” effect, stemming from susceptible lithium stuck in the solid electrolyte, triggers an inadequate reaction of the intermediate region of electrodes. Then, we construct locally accelerated ion paths activating the lithium trapping, indicating that this strategy can significantly guide the sustainable battery design for next-generation energy storage.