Establishing an elastic electron/lithium-ion transport network via in situ crosslinking for stabilizing interphases in SiOx electrodes

Abstract

The significant volumetric fluctuations experienced by high-capacity silicon-based electrodes during cycling lead to the disintegration of conductive frameworks and destabilization of the solid-electrolyte interphase (SEI). To overcome these challenges, an in situ thiol-ene click reaction is employed to fabricate an elastic electron/lithium-ion (e⁻/Li⁺)-conducting polymer network that uniformly binds SiO_x active materials. The proposed polymer incorporates rigid backbone segments that enhance electron conduction, along with flexible linkers that facilitate Li⁺ transport and stress dissipation within the SiO_x electrode, thereby stabilizing the interfacial charge transfer on SiO_x. By reducing the initial expansion rate of the SiO_x electrode from 157% to 65%, the stable polymeric network effectively mitigates SEI degradation during cycling. As a result, the in-situ-crosslinked polymer framework enables improved capacity retention (82.7% after 250 cycles) and rate performance. By simultaneously strengthening the ion and electron transport pathways, this work offers new avenues for the future design of high-capacity negative electrodes.