Interfacial encapsulation stress management of micron-sized porous SiO anodes for high-energy lithium-ion batteries

Abstract

Encapsulating micron-sized porous silicon monoxide (SiO) with conductive carbon materials has shown enormous potential as practical high-performance anodes for lithium-ion batteries. However, constructing an ideal integral interfacial coating layer to accommodate the dynamic evolution of SiO microparticles remains a huge challenge. Here, the stress fields of SiO microparticles with three types of coating strategies are studied via finite element modeling. The results demonstrate that the soft coating can better alleviate the tensile stress during lithiation processes compared with other hard and hard–soft dual-layer coatings. Consequently, a robust SiO-based anode is intelligently designed, in which porous SiO microparticles are encapsulated in a graphene hydrogel monolith (p-SiO@rGO). The ductility and sliding characteristics of the highly interlinked graphene architecture effectively release the large tensile stress of SiO particles upon lithiation, ensuring the structural integrality of the entire electrode. The p-SiO@rGO electrode shows a superior lithium storage capacity, including high initial coulombic efficiency (76.4%), long cycling durability (589.7 mA h g⁻¹ at 2 A g⁻¹, 1000 cycles later) and prominent rate performance (841.6 mA h g⁻¹ at 5 A g⁻¹). This study provides a helpful guideline for designing high-performance SiO-based anodes with long durability for practical energy storage.