Unveiling the In Situ Evolution of Li₂O‐Rich Solid Electrolyte Interface on CoO_x Embedded Carbon Fibers as Li Anode Host

Abstract

Modification of three‐dimensional (3D) carbon hosts with metal oxides has been considered as advantageous for the formation of Li2O‐rich solid electrolyte interface (SEI), which could show fast Li+ diffusion, and meanwhile alleviate dendrite problems caused by fragility and non‐uniformity of native SEIs. However, the lack of convincing experimental evidence has made it difficult to unveil the true origin of oxygen in Li2O‐rich SEIs until now. Herein, we successfully prepared CoOx embedded carbon nanofibers (CNF‐CoOx) as high‐performance Li anode hosts. By employing 18O isotope labeling, we aimed to elucidate the role of CoOx during SEI evolution that CoOx contributes significantly to Li2O formation by delivering oxygen. Benefiting from the rich Li2O content, the as‐formed SEIs greatly improve the Li+ migration kinetics, and therefore the CNF‐CoOx@Li anode could exhibit excellent cycling stability in half, symmetrical, and full cells.This article is protected by copyright. All rights reserved